Insect parasites known as body lice depend on human blood. The body louse, Pthirus pubis, the crab or pubic louse, Pediculus humanus capitis, and the head louse are the 3 kinds of lice that feed on people. Entomologists disagree on the correct classification for body and head lice; some see them as 2 different subspecies, while others combine them under one heading.
Body lice are known as Pediculus humanus by those who see them as two separate species, while they are known as Pediculus humanus humanus by others who see them as a single species. Body lice are frequently referred to as Pediculus humanus corporis in scientific journals, although this is incorrect according to the International Commission on Zoological Nomenclature guidelines.
Studies have shown that body & head lice are closely linked, and genetic research has shown that body lice only have one chromosome that is unique to them. In contrast to the public and head lice, body lice dwell and release their eggs in the seams of garments and bedding, only migrating to the skin to eat. The capacity of body lice to spread bacterial infections like epidemic typhus, trench fever, & relapsing fever to humans is the most important distinction between head and body lice.
Epidemiology
Body lice can only move by close interaction because they cannot jump or fly. However, they can also spread through garments, bed sheets, & towels. Poor personal hygiene, a lack of availability to clean clothing, & crowded environments all contribute to infestations since these factors make it easier for lice to spread through direct contact with individuals.
The majority of outbreaks take place in places where huge populations dwell in unhygienic conditions, including prisons and camps for large numbers of refugees fleeing conflict, famine, and natural catastrophes. Because homeless people don’t have access to clean clothing and showers, body lice infections are most widespread among them in the U.S. and other industrialized nations.
Throughout the world, outbreaks of body lice infections and diseases transmitted by louse bites have been observed in remote regions of the Peruvian Andes, rural communities in Russia, and prisons & refugee camps in eastern and central Africa.
Anatomy
Pathophysiology
Numerous thousands of mites, each biting on average five times each day, can be present in an infestation of body lice. Body lice eat by puncturing the skin, injecting saliva with an anticoagulant, & then sucking the blood meal into their digestive systems. Body louse bites can result in a range of skin conditions as well as severe pruritus, which is thought to be brought on by an allergic and inflammatory response to the saliva of the louse. When pruritic bites are scratched vigorously, the skin might become excoriated, which can result in serious secondary infections from bacteria.
The potential of body lice to spread bacterial infections, most particularly relapsing fever from Borrelia recurrentis, epidemic (louse-borne) typhus from Rickettsia prowazekii, & trench fever from Bartonella quintana, has the biggest medical effect. Instead of being spread by louse bites, trench fever & epidemic typhus are spread by contaminated excrement. The body louse frequently deposits its excrement onto the skin while eating, which might unintentionally rub against the site of the bite, eyes, and mucosa.
The inhaling of aerosolized fecal dust, which has been identified as a possible source of contamination for medical professionals, is another way that Rickettsia prowazekii might be transmitted. Relapsing fever, which is brought on by the bacteria Borrelia recurrentis, is not spread by contact with infected feces like trench fever or epidemic typhus. When an individual crushes an infectious louse, the germs enter the bite area or the tissue of the hand or fingers that were used to crush the louse, causing infection.
Additionally, after smashing the louse, a person runs the risk of contracting the infection if they wipe their eyes and put their hands in their mouth. Serratia marcescens, Acinetobacter baumannii, & Salmonella typhi are other harmful bacteria that have been linked to body lice. Body lice have been shown to have the Genome of Yersinia pestis, the bacterium that causes bubonic plague, and it is thought that they may act as additional carriers for the disease.
Etiology
Body lice are ectoparasites with a global distribution that depends on human blood for food. Throughout their life cycle, they take on three different forms, beginning with the nit, or egg, and moving on to the nymph & adult stages. Nits are round and can be either white or yellow, just like head lice.
Body lice, on the other hand, deposit their eggs in the seams of garments, as opposed to head lice; they adhere their eggs to the proximate hair strands. A nymph is a premature louse, which, other than its lower size, resembles an adult louse in appearance. Adult head lice measure 2.5 to 3.5 centimeters in length, have six legs, and are flat in shape.
They range in color from tan to greyish white. Body lice can survive up to 60 days and feed one to five times every day. Body lice will expire after being isolated from a human host for a week.
Genetics
Prognostic Factors
If patients have frequent access to showers and at least weekly use of fresh clothes and bedding, the chances of getting rid of body lice infections are very favorable. Louse-borne infections are associated with significant morbidity and death, although they can be significantly decreased with early detection and the right antibiotic treatment.
Vasculitis brought on by epidemic typhus can result in organ dysfunction, gangrene, limb ischemia, & malfunction of the CNS. With the right antibiotic treatment, mortality falls to 3%–4% from 20%–40% in symptomatic patients.
If left untreated, the death rate from relapsing fever, louse-borne, is roughly 40%, although it decreases to only about 4% with therapy. In immunocompetent individuals, trench fever, which is brought on by B. quintana, typically resolves on its own, but it can occasionally progress to endocarditis, which raises the risk of morbidity & fatality.
Clinical History
Clinical History
A patient may seek the help of a healthcare professional after noticing lice and nits. In most cases, head louse infestation is initially diagnosed by teachers and parents. Head lice infestations are typically discovered by a school nurse (regular nit inspections by school nurses are common in many parts of the United States), or a generic letter is sent home to parents advising them to check their children for lice. Concerned parents then take their children to their doctor or the nearest emergency room.
The most typical indication of an infestation is pruritus. Because of their severe night-time itching, children frequently have problems falling asleep. The back of the neck, the scalp, as well as the postauricular regions, are among the body parts impacted by head louse infection. Scratching can lead to bacterial sores and subsequent illness. However, whether it is the initial infestation or if the infestation is mild, lice infestation may not show any symptoms.
When P corporis lice transfer from the clothing to the body to feed, patients with an infestation suffer from nocturnal pruritus, especially in the truncal, axillary, & groin areas. Given that body louse infestation typically affects people of poor socioeconomic class, the investigating doctor should ask the patient about their living situation and socioeconomic background.
P-pubis-infected adults frequently engage in sexual activity and have body and groin hair involvement. It is possible to distinguish between a P pubis infestation and a body or head louse infection by looking for symptoms of pruritus in the axillae, groin, eyebrows, or eyelashes. As the parents are typically the source of infection, it is important to ask them if they themselves have P pubis on their eyebrows and eyelids. Patients may mention accompanying characteristics, such as papules or wheals, that show biting reactions.
Physical Examination
Physical examination
Any pediculosis can be identified by looking for eggs/nits, mature lice, or nymphs. Finding live lice is necessary for a conclusive diagnosis of a current infestation. However, if they are within 6 mm of the scalp, the active infestation is likely. Nits are not diagnostic of an active infestation. In warm areas, viable nits may be discovered 8 or more inches from the scalp. While lice nymphs and adults are unable to leap or jump, they may move quickly through dry hair.
To remove live lice and nymphs, wet the hair and use a fine-tooth “bug-busting” comb to loosen eggs. The diagnosis is aided by the use of a magnifying glass and knowledge of where to look for lice (depending on each species’ biology). Head lice have a maximum speed of 23 cm/min. Attaching a piece of the clear adhesive tape to the affected regions is a useful trick.
The tape, which later serves as a convenient coverslip for a microscopic slide, attracts lice. The size of a sesame seed, mature head lice have an extended body, three pairs of legs, and small anterior mouthparts. Pubic lice can be identified by their wide bodies and claws. Nits have a flask-like form, are clear, and are about 1 mm long.
P humanus capitis
Scalp itching, impetigo, and, less frequently, occipital lymphadenopathy are signs of head louse infestation. When the scalp is examined, nits, adult lice, excoriations, and dark louse excrement particles are all visible. The retroauricular scalp often has the worst infestation. The use of a louse comb is more effective than a direct visual inspection of the scalp for the identification of P capitis infestation. Excoriations, subsequent bacterial infestation, and expansion of the posterior auricular & cervical nodes are all frequently caused by pruritus.
Rarely does a louse infection come with a generalized exanthema (pediculid), which is comparable to a viral exanthema and pityriasis rosea. If there are excoriations, impetigo, a secondary infection, should be ruled out and managed if it is. Depending on how long it has been after the blood feast, bite reactions may appear as itchy, red papules, or wheals. Rarely is the heavily infected & untreated patients’ hair twisted with exudates, making the area more susceptible to a fungus invasion. The outcome is a plica polonica, a foul-smelling mass. Under the clump of matted hair, there are lots of lice & nits.
Nits
By attempting to extract the nit from the hair, you can tell it apart from dried hairspray and hair casts; nits, on the other hand, are firmly linked to the hair. In case the doctor is still unclear, a Wood lamp examination can be done. When illuminated by a Wood lamp, live nits are fluorescent white, while empty nits are luminous grey.
Nits are connected to the hair shafts slightly above the level of the scalp because nits need body heat to incubate their eggs. The separation of nits from the scalp can be used to calculate the length of the infestation because human scalp hair grows at a rate of roughly 10 mm/month (0.37 mm/day). Nits are nonviable empty egg cases that can be detected a few millimeters from the scalp. They suggest persistent infection.
P humanus corporis
Multiple bite-related lesions are found during a physical examination in cases of body louse infection. Erythematous papules that are 2-4 mm in diameter and have an erythematous base characterize uninfected bites. Although bites can occur anywhere on the body, they are most common in the groin, axillae, & trunk (i.e., areas most often covered by clothing). The face, feet, and arms are, therefore, not typically impacted. Except for the edges, body lice typically stay away from the scalp.
It is thought that the presence of maculae cerulea is a pathognomonic sign of a lice infestation. The blue-gray maculae, known as maculae cerulea are actually skin discolorations brought on by bug bites. The change in skin color associated with maculae cerulea is thought to be caused by enzymes that stimulate the breakdown of human bilirubin to biliverdin in the saliva of the louse. There may be severe itching if you have an allergic reaction to a louse bite.
Excoriations may lead to secondary infections. The patient’s clothing must be closely examined for crawling lice and nits in order to diagnose body lice. Common dwelling places are the interior seams of garments worn in the axillae & groin areas. A body louse could occasionally be spotted feeding and creeping on the skin. Although up to 1000 lice can be found in clothing, the average number of body lice per host is around 10.
A person who has had a body louse infection for a long time may develop a condition called vagabond skin. This illness is also known as vagabond sickness. After years of attacks, followed by rubbing & excoriations, the skin becomes thicker and darker. Additionally, it’s crucial to check for any systemic diseases that can be connected to a vector-borne sickness like P corporis.
P pubis
The main sign of pubic lice infection is itching in the areas affected. The presence of pathognomonic maculae cerulea related to bites is another clinical sign of pubic louse infection. It’s possible to find crusts and little areas of blood discoloration on underpants. Usually, pubic hair is the place. The pubic hair typically has noticeable pubic lice & nits all over it. Pubic lice are less mobile than other lice, therefore, you’re more likely to find them in infected areas, latching onto the hairs close to the surface of the skin.
Hair on the axillae, belly, anus, upper arms, chest, eyebrows, eyelashes, and chest. may get infested. Rarely is a location of infestation the facial hair (moustache, beard, eyebrows, and eyelashes). Involvement of the scalp is uncommon and typically limited to the periphery. Involvement of the eyelashes in people without genital participation is uncommon.
The brows & eyelashes are frequently infested in prepubescent children. Not head louse infection, but pubic louse infection is the cause of eyelid nits. Children may contract P pubis infection from an infected parent via sexual contact or as a result of abuse; the child should be checked for symptoms of abuse. Excoriations frequently occur. Additionally, associated with pubic louse infection have been reports of inguinal & axillary lymphadenopathy.
Age group
Associated comorbidity
Associated activity
Acuity of presentation
Differential Diagnoses
Differential Diagnoses
Pseudonits (hair casts) must be separated from true nit infestation. The inner root sheath of the hair follicle leaves behind ring-shaped remnants known as hair casts. They can travel freely and amorphously along the hair fiber. There are many conditions that might itch the scalp. Erythema & scaling are the symptoms of seborrheic dermatitis. The head, brows, nasolabial folds, and middle chest are all affected.
Inflamed follicular pustules and papules, black crusts, & scarring are the symptoms of acne necrotica. Patients frequently pick at the lesions because it is so itchy. Primitive psocid lice that live free in the environment eat rotting stuff found in old books, leaves, & wildlife habitats. When kids enter an infested library and doghouse, they could spread human scalp infection. Psocids may clearly be identified from Anoplura lice thanks to their large hind legs, powerful jaws, huge heads & long antennae.
The following are additional head louse differential diagnoses:
Delusions
Irregularities in the hair shaft (i.e., trichorrhexis nodosa, monilethrix)
Piedra
Dermatophyte infection
Dried hairspray
Dirt
Desquamated cells
Scabs
Fibers
Dandruff
Body louse infestations might have the following differential diagnoses:
Postinflammatory hyperpigmentation
Impetigo
Xerosis with excoriations
Delusions of parasitosis
Acne
Scabies
Insect Bites
Folliculitis
The following are additional diagnoses for a pubic louse infestation:
Conjunctivitis
Contact dermatitis
Delusions of parasitosis
Folliculitis
Dermatophyte infection
Laboratory Studies
Imaging Studies
Procedures
Histologic Findings
Staging
Treatment Paradigm
Body lice are typically treated without the use of a pediculicide since better hygiene, such as taking showers and washing clothes in hot water that exceeds 50 C, will usually get rid of the infection. The hot cycle of the washing machine should be used to wash and dry all garments, linens, & towels. Topical corticosteroids & systemic antihistamines can be used to relieve itching. Systemic antibiotics are used appropriately to treat subsequent skin disorders.
Although pediculicides are not necessary for the treatment of body lice infestations, they are frequently used, particularly when body nits and lice are discovered on body hair or when there is a co-infection with pubic lice, head lice, or scabies. The same medications used to treat pubic & head lice are used in these situations, most frequently permethrin lotion administered to the entire body for eight to ten hours.
Additionally, 0.9 percent spinosad topical suspension, 0.5 percent malathion lotion, 1 percent lindane shampoo, and 0.5 percent ivermectin lotion are available as therapies. Due to a number of possibly harmful side effects, such as neurotoxicity & seizures, lindane is not advised as a first-line therapy. Chemical pesticides may need to be applied to the environment in particular situations, including such refugee camps with high populations, in order to stop the spread of illnesses brought on by lice and body lice.
Insect parasites known as body lice depend on human blood. The body louse, Pthirus pubis, the crab or pubic louse, Pediculus humanus capitis, and the head louse are the 3 kinds of lice that feed on people. Entomologists disagree on the correct classification for body and head lice; some see them as 2 different subspecies, while others combine them under one heading.
Body lice are known as Pediculus humanus by those who see them as two separate species, while they are known as Pediculus humanus humanus by others who see them as a single species. Body lice are frequently referred to as Pediculus humanus corporis in scientific journals, although this is incorrect according to the International Commission on Zoological Nomenclature guidelines.
Studies have shown that body & head lice are closely linked, and genetic research has shown that body lice only have one chromosome that is unique to them. In contrast to the public and head lice, body lice dwell and release their eggs in the seams of garments and bedding, only migrating to the skin to eat. The capacity of body lice to spread bacterial infections like epidemic typhus, trench fever, & relapsing fever to humans is the most important distinction between head and body lice.
Body lice can only move by close interaction because they cannot jump or fly. However, they can also spread through garments, bed sheets, & towels. Poor personal hygiene, a lack of availability to clean clothing, & crowded environments all contribute to infestations since these factors make it easier for lice to spread through direct contact with individuals.
The majority of outbreaks take place in places where huge populations dwell in unhygienic conditions, including prisons and camps for large numbers of refugees fleeing conflict, famine, and natural catastrophes. Because homeless people don’t have access to clean clothing and showers, body lice infections are most widespread among them in the U.S. and other industrialized nations.
Throughout the world, outbreaks of body lice infections and diseases transmitted by louse bites have been observed in remote regions of the Peruvian Andes, rural communities in Russia, and prisons & refugee camps in eastern and central Africa.
Numerous thousands of mites, each biting on average five times each day, can be present in an infestation of body lice. Body lice eat by puncturing the skin, injecting saliva with an anticoagulant, & then sucking the blood meal into their digestive systems. Body louse bites can result in a range of skin conditions as well as severe pruritus, which is thought to be brought on by an allergic and inflammatory response to the saliva of the louse. When pruritic bites are scratched vigorously, the skin might become excoriated, which can result in serious secondary infections from bacteria.
The potential of body lice to spread bacterial infections, most particularly relapsing fever from Borrelia recurrentis, epidemic (louse-borne) typhus from Rickettsia prowazekii, & trench fever from Bartonella quintana, has the biggest medical effect. Instead of being spread by louse bites, trench fever & epidemic typhus are spread by contaminated excrement. The body louse frequently deposits its excrement onto the skin while eating, which might unintentionally rub against the site of the bite, eyes, and mucosa.
The inhaling of aerosolized fecal dust, which has been identified as a possible source of contamination for medical professionals, is another way that Rickettsia prowazekii might be transmitted. Relapsing fever, which is brought on by the bacteria Borrelia recurrentis, is not spread by contact with infected feces like trench fever or epidemic typhus. When an individual crushes an infectious louse, the germs enter the bite area or the tissue of the hand or fingers that were used to crush the louse, causing infection.
Additionally, after smashing the louse, a person runs the risk of contracting the infection if they wipe their eyes and put their hands in their mouth. Serratia marcescens, Acinetobacter baumannii, & Salmonella typhi are other harmful bacteria that have been linked to body lice. Body lice have been shown to have the Genome of Yersinia pestis, the bacterium that causes bubonic plague, and it is thought that they may act as additional carriers for the disease.
Body lice are ectoparasites with a global distribution that depends on human blood for food. Throughout their life cycle, they take on three different forms, beginning with the nit, or egg, and moving on to the nymph & adult stages. Nits are round and can be either white or yellow, just like head lice.
Body lice, on the other hand, deposit their eggs in the seams of garments, as opposed to head lice; they adhere their eggs to the proximate hair strands. A nymph is a premature louse, which, other than its lower size, resembles an adult louse in appearance. Adult head lice measure 2.5 to 3.5 centimeters in length, have six legs, and are flat in shape.
They range in color from tan to greyish white. Body lice can survive up to 60 days and feed one to five times every day. Body lice will expire after being isolated from a human host for a week.
If patients have frequent access to showers and at least weekly use of fresh clothes and bedding, the chances of getting rid of body lice infections are very favorable. Louse-borne infections are associated with significant morbidity and death, although they can be significantly decreased with early detection and the right antibiotic treatment.
Vasculitis brought on by epidemic typhus can result in organ dysfunction, gangrene, limb ischemia, & malfunction of the CNS. With the right antibiotic treatment, mortality falls to 3%–4% from 20%–40% in symptomatic patients.
If left untreated, the death rate from relapsing fever, louse-borne, is roughly 40%, although it decreases to only about 4% with therapy. In immunocompetent individuals, trench fever, which is brought on by B. quintana, typically resolves on its own, but it can occasionally progress to endocarditis, which raises the risk of morbidity & fatality.
Clinical History
A patient may seek the help of a healthcare professional after noticing lice and nits. In most cases, head louse infestation is initially diagnosed by teachers and parents. Head lice infestations are typically discovered by a school nurse (regular nit inspections by school nurses are common in many parts of the United States), or a generic letter is sent home to parents advising them to check their children for lice. Concerned parents then take their children to their doctor or the nearest emergency room.
The most typical indication of an infestation is pruritus. Because of their severe night-time itching, children frequently have problems falling asleep. The back of the neck, the scalp, as well as the postauricular regions, are among the body parts impacted by head louse infection. Scratching can lead to bacterial sores and subsequent illness. However, whether it is the initial infestation or if the infestation is mild, lice infestation may not show any symptoms.
When P corporis lice transfer from the clothing to the body to feed, patients with an infestation suffer from nocturnal pruritus, especially in the truncal, axillary, & groin areas. Given that body louse infestation typically affects people of poor socioeconomic class, the investigating doctor should ask the patient about their living situation and socioeconomic background.
P-pubis-infected adults frequently engage in sexual activity and have body and groin hair involvement. It is possible to distinguish between a P pubis infestation and a body or head louse infection by looking for symptoms of pruritus in the axillae, groin, eyebrows, or eyelashes. As the parents are typically the source of infection, it is important to ask them if they themselves have P pubis on their eyebrows and eyelids. Patients may mention accompanying characteristics, such as papules or wheals, that show biting reactions.
Physical examination
Any pediculosis can be identified by looking for eggs/nits, mature lice, or nymphs. Finding live lice is necessary for a conclusive diagnosis of a current infestation. However, if they are within 6 mm of the scalp, the active infestation is likely. Nits are not diagnostic of an active infestation. In warm areas, viable nits may be discovered 8 or more inches from the scalp. While lice nymphs and adults are unable to leap or jump, they may move quickly through dry hair.
To remove live lice and nymphs, wet the hair and use a fine-tooth “bug-busting” comb to loosen eggs. The diagnosis is aided by the use of a magnifying glass and knowledge of where to look for lice (depending on each species’ biology). Head lice have a maximum speed of 23 cm/min. Attaching a piece of the clear adhesive tape to the affected regions is a useful trick.
The tape, which later serves as a convenient coverslip for a microscopic slide, attracts lice. The size of a sesame seed, mature head lice have an extended body, three pairs of legs, and small anterior mouthparts. Pubic lice can be identified by their wide bodies and claws. Nits have a flask-like form, are clear, and are about 1 mm long.
P humanus capitis
Scalp itching, impetigo, and, less frequently, occipital lymphadenopathy are signs of head louse infestation. When the scalp is examined, nits, adult lice, excoriations, and dark louse excrement particles are all visible. The retroauricular scalp often has the worst infestation. The use of a louse comb is more effective than a direct visual inspection of the scalp for the identification of P capitis infestation. Excoriations, subsequent bacterial infestation, and expansion of the posterior auricular & cervical nodes are all frequently caused by pruritus.
Rarely does a louse infection come with a generalized exanthema (pediculid), which is comparable to a viral exanthema and pityriasis rosea. If there are excoriations, impetigo, a secondary infection, should be ruled out and managed if it is. Depending on how long it has been after the blood feast, bite reactions may appear as itchy, red papules, or wheals. Rarely is the heavily infected & untreated patients’ hair twisted with exudates, making the area more susceptible to a fungus invasion. The outcome is a plica polonica, a foul-smelling mass. Under the clump of matted hair, there are lots of lice & nits.
Nits
By attempting to extract the nit from the hair, you can tell it apart from dried hairspray and hair casts; nits, on the other hand, are firmly linked to the hair. In case the doctor is still unclear, a Wood lamp examination can be done. When illuminated by a Wood lamp, live nits are fluorescent white, while empty nits are luminous grey.
Nits are connected to the hair shafts slightly above the level of the scalp because nits need body heat to incubate their eggs. The separation of nits from the scalp can be used to calculate the length of the infestation because human scalp hair grows at a rate of roughly 10 mm/month (0.37 mm/day). Nits are nonviable empty egg cases that can be detected a few millimeters from the scalp. They suggest persistent infection.
P humanus corporis
Multiple bite-related lesions are found during a physical examination in cases of body louse infection. Erythematous papules that are 2-4 mm in diameter and have an erythematous base characterize uninfected bites. Although bites can occur anywhere on the body, they are most common in the groin, axillae, & trunk (i.e., areas most often covered by clothing). The face, feet, and arms are, therefore, not typically impacted. Except for the edges, body lice typically stay away from the scalp.
It is thought that the presence of maculae cerulea is a pathognomonic sign of a lice infestation. The blue-gray maculae, known as maculae cerulea are actually skin discolorations brought on by bug bites. The change in skin color associated with maculae cerulea is thought to be caused by enzymes that stimulate the breakdown of human bilirubin to biliverdin in the saliva of the louse. There may be severe itching if you have an allergic reaction to a louse bite.
Excoriations may lead to secondary infections. The patient’s clothing must be closely examined for crawling lice and nits in order to diagnose body lice. Common dwelling places are the interior seams of garments worn in the axillae & groin areas. A body louse could occasionally be spotted feeding and creeping on the skin. Although up to 1000 lice can be found in clothing, the average number of body lice per host is around 10.
A person who has had a body louse infection for a long time may develop a condition called vagabond skin. This illness is also known as vagabond sickness. After years of attacks, followed by rubbing & excoriations, the skin becomes thicker and darker. Additionally, it’s crucial to check for any systemic diseases that can be connected to a vector-borne sickness like P corporis.
P pubis
The main sign of pubic lice infection is itching in the areas affected. The presence of pathognomonic maculae cerulea related to bites is another clinical sign of pubic louse infection. It’s possible to find crusts and little areas of blood discoloration on underpants. Usually, pubic hair is the place. The pubic hair typically has noticeable pubic lice & nits all over it. Pubic lice are less mobile than other lice, therefore, you’re more likely to find them in infected areas, latching onto the hairs close to the surface of the skin.
Hair on the axillae, belly, anus, upper arms, chest, eyebrows, eyelashes, and chest. may get infested. Rarely is a location of infestation the facial hair (moustache, beard, eyebrows, and eyelashes). Involvement of the scalp is uncommon and typically limited to the periphery. Involvement of the eyelashes in people without genital participation is uncommon.
The brows & eyelashes are frequently infested in prepubescent children. Not head louse infection, but pubic louse infection is the cause of eyelid nits. Children may contract P pubis infection from an infected parent via sexual contact or as a result of abuse; the child should be checked for symptoms of abuse. Excoriations frequently occur. Additionally, associated with pubic louse infection have been reports of inguinal & axillary lymphadenopathy.
Differential Diagnoses
Pseudonits (hair casts) must be separated from true nit infestation. The inner root sheath of the hair follicle leaves behind ring-shaped remnants known as hair casts. They can travel freely and amorphously along the hair fiber. There are many conditions that might itch the scalp. Erythema & scaling are the symptoms of seborrheic dermatitis. The head, brows, nasolabial folds, and middle chest are all affected.
Inflamed follicular pustules and papules, black crusts, & scarring are the symptoms of acne necrotica. Patients frequently pick at the lesions because it is so itchy. Primitive psocid lice that live free in the environment eat rotting stuff found in old books, leaves, & wildlife habitats. When kids enter an infested library and doghouse, they could spread human scalp infection. Psocids may clearly be identified from Anoplura lice thanks to their large hind legs, powerful jaws, huge heads & long antennae.
The following are additional head louse differential diagnoses:
Delusions
Irregularities in the hair shaft (i.e., trichorrhexis nodosa, monilethrix)
Piedra
Dermatophyte infection
Dried hairspray
Dirt
Desquamated cells
Scabs
Fibers
Dandruff
Body louse infestations might have the following differential diagnoses:
Postinflammatory hyperpigmentation
Impetigo
Xerosis with excoriations
Delusions of parasitosis
Acne
Scabies
Insect Bites
Folliculitis
The following are additional diagnoses for a pubic louse infestation:
Conjunctivitis
Contact dermatitis
Delusions of parasitosis
Folliculitis
Dermatophyte infection
Body lice are typically treated without the use of a pediculicide since better hygiene, such as taking showers and washing clothes in hot water that exceeds 50 C, will usually get rid of the infection. The hot cycle of the washing machine should be used to wash and dry all garments, linens, & towels. Topical corticosteroids & systemic antihistamines can be used to relieve itching. Systemic antibiotics are used appropriately to treat subsequent skin disorders.
Although pediculicides are not necessary for the treatment of body lice infestations, they are frequently used, particularly when body nits and lice are discovered on body hair or when there is a co-infection with pubic lice, head lice, or scabies. The same medications used to treat pubic & head lice are used in these situations, most frequently permethrin lotion administered to the entire body for eight to ten hours.
Additionally, 0.9 percent spinosad topical suspension, 0.5 percent malathion lotion, 1 percent lindane shampoo, and 0.5 percent ivermectin lotion are available as therapies. Due to a number of possibly harmful side effects, such as neurotoxicity & seizures, lindane is not advised as a first-line therapy. Chemical pesticides may need to be applied to the environment in particular situations, including such refugee camps with high populations, in order to stop the spread of illnesses brought on by lice and body lice.
Insect parasites known as body lice depend on human blood. The body louse, Pthirus pubis, the crab or pubic louse, Pediculus humanus capitis, and the head louse are the 3 kinds of lice that feed on people. Entomologists disagree on the correct classification for body and head lice; some see them as 2 different subspecies, while others combine them under one heading.
Body lice are known as Pediculus humanus by those who see them as two separate species, while they are known as Pediculus humanus humanus by others who see them as a single species. Body lice are frequently referred to as Pediculus humanus corporis in scientific journals, although this is incorrect according to the International Commission on Zoological Nomenclature guidelines.
Studies have shown that body & head lice are closely linked, and genetic research has shown that body lice only have one chromosome that is unique to them. In contrast to the public and head lice, body lice dwell and release their eggs in the seams of garments and bedding, only migrating to the skin to eat. The capacity of body lice to spread bacterial infections like epidemic typhus, trench fever, & relapsing fever to humans is the most important distinction between head and body lice.
Body lice can only move by close interaction because they cannot jump or fly. However, they can also spread through garments, bed sheets, & towels. Poor personal hygiene, a lack of availability to clean clothing, & crowded environments all contribute to infestations since these factors make it easier for lice to spread through direct contact with individuals.
The majority of outbreaks take place in places where huge populations dwell in unhygienic conditions, including prisons and camps for large numbers of refugees fleeing conflict, famine, and natural catastrophes. Because homeless people don’t have access to clean clothing and showers, body lice infections are most widespread among them in the U.S. and other industrialized nations.
Throughout the world, outbreaks of body lice infections and diseases transmitted by louse bites have been observed in remote regions of the Peruvian Andes, rural communities in Russia, and prisons & refugee camps in eastern and central Africa.
Numerous thousands of mites, each biting on average five times each day, can be present in an infestation of body lice. Body lice eat by puncturing the skin, injecting saliva with an anticoagulant, & then sucking the blood meal into their digestive systems. Body louse bites can result in a range of skin conditions as well as severe pruritus, which is thought to be brought on by an allergic and inflammatory response to the saliva of the louse. When pruritic bites are scratched vigorously, the skin might become excoriated, which can result in serious secondary infections from bacteria.
The potential of body lice to spread bacterial infections, most particularly relapsing fever from Borrelia recurrentis, epidemic (louse-borne) typhus from Rickettsia prowazekii, & trench fever from Bartonella quintana, has the biggest medical effect. Instead of being spread by louse bites, trench fever & epidemic typhus are spread by contaminated excrement. The body louse frequently deposits its excrement onto the skin while eating, which might unintentionally rub against the site of the bite, eyes, and mucosa.
The inhaling of aerosolized fecal dust, which has been identified as a possible source of contamination for medical professionals, is another way that Rickettsia prowazekii might be transmitted. Relapsing fever, which is brought on by the bacteria Borrelia recurrentis, is not spread by contact with infected feces like trench fever or epidemic typhus. When an individual crushes an infectious louse, the germs enter the bite area or the tissue of the hand or fingers that were used to crush the louse, causing infection.
Additionally, after smashing the louse, a person runs the risk of contracting the infection if they wipe their eyes and put their hands in their mouth. Serratia marcescens, Acinetobacter baumannii, & Salmonella typhi are other harmful bacteria that have been linked to body lice. Body lice have been shown to have the Genome of Yersinia pestis, the bacterium that causes bubonic plague, and it is thought that they may act as additional carriers for the disease.
Body lice are ectoparasites with a global distribution that depends on human blood for food. Throughout their life cycle, they take on three different forms, beginning with the nit, or egg, and moving on to the nymph & adult stages. Nits are round and can be either white or yellow, just like head lice.
Body lice, on the other hand, deposit their eggs in the seams of garments, as opposed to head lice; they adhere their eggs to the proximate hair strands. A nymph is a premature louse, which, other than its lower size, resembles an adult louse in appearance. Adult head lice measure 2.5 to 3.5 centimeters in length, have six legs, and are flat in shape.
They range in color from tan to greyish white. Body lice can survive up to 60 days and feed one to five times every day. Body lice will expire after being isolated from a human host for a week.
If patients have frequent access to showers and at least weekly use of fresh clothes and bedding, the chances of getting rid of body lice infections are very favorable. Louse-borne infections are associated with significant morbidity and death, although they can be significantly decreased with early detection and the right antibiotic treatment.
Vasculitis brought on by epidemic typhus can result in organ dysfunction, gangrene, limb ischemia, & malfunction of the CNS. With the right antibiotic treatment, mortality falls to 3%–4% from 20%–40% in symptomatic patients.
If left untreated, the death rate from relapsing fever, louse-borne, is roughly 40%, although it decreases to only about 4% with therapy. In immunocompetent individuals, trench fever, which is brought on by B. quintana, typically resolves on its own, but it can occasionally progress to endocarditis, which raises the risk of morbidity & fatality.
Clinical History
A patient may seek the help of a healthcare professional after noticing lice and nits. In most cases, head louse infestation is initially diagnosed by teachers and parents. Head lice infestations are typically discovered by a school nurse (regular nit inspections by school nurses are common in many parts of the United States), or a generic letter is sent home to parents advising them to check their children for lice. Concerned parents then take their children to their doctor or the nearest emergency room.
The most typical indication of an infestation is pruritus. Because of their severe night-time itching, children frequently have problems falling asleep. The back of the neck, the scalp, as well as the postauricular regions, are among the body parts impacted by head louse infection. Scratching can lead to bacterial sores and subsequent illness. However, whether it is the initial infestation or if the infestation is mild, lice infestation may not show any symptoms.
When P corporis lice transfer from the clothing to the body to feed, patients with an infestation suffer from nocturnal pruritus, especially in the truncal, axillary, & groin areas. Given that body louse infestation typically affects people of poor socioeconomic class, the investigating doctor should ask the patient about their living situation and socioeconomic background.
P-pubis-infected adults frequently engage in sexual activity and have body and groin hair involvement. It is possible to distinguish between a P pubis infestation and a body or head louse infection by looking for symptoms of pruritus in the axillae, groin, eyebrows, or eyelashes. As the parents are typically the source of infection, it is important to ask them if they themselves have P pubis on their eyebrows and eyelids. Patients may mention accompanying characteristics, such as papules or wheals, that show biting reactions.
Physical examination
Any pediculosis can be identified by looking for eggs/nits, mature lice, or nymphs. Finding live lice is necessary for a conclusive diagnosis of a current infestation. However, if they are within 6 mm of the scalp, the active infestation is likely. Nits are not diagnostic of an active infestation. In warm areas, viable nits may be discovered 8 or more inches from the scalp. While lice nymphs and adults are unable to leap or jump, they may move quickly through dry hair.
To remove live lice and nymphs, wet the hair and use a fine-tooth “bug-busting” comb to loosen eggs. The diagnosis is aided by the use of a magnifying glass and knowledge of where to look for lice (depending on each species’ biology). Head lice have a maximum speed of 23 cm/min. Attaching a piece of the clear adhesive tape to the affected regions is a useful trick.
The tape, which later serves as a convenient coverslip for a microscopic slide, attracts lice. The size of a sesame seed, mature head lice have an extended body, three pairs of legs, and small anterior mouthparts. Pubic lice can be identified by their wide bodies and claws. Nits have a flask-like form, are clear, and are about 1 mm long.
P humanus capitis
Scalp itching, impetigo, and, less frequently, occipital lymphadenopathy are signs of head louse infestation. When the scalp is examined, nits, adult lice, excoriations, and dark louse excrement particles are all visible. The retroauricular scalp often has the worst infestation. The use of a louse comb is more effective than a direct visual inspection of the scalp for the identification of P capitis infestation. Excoriations, subsequent bacterial infestation, and expansion of the posterior auricular & cervical nodes are all frequently caused by pruritus.
Rarely does a louse infection come with a generalized exanthema (pediculid), which is comparable to a viral exanthema and pityriasis rosea. If there are excoriations, impetigo, a secondary infection, should be ruled out and managed if it is. Depending on how long it has been after the blood feast, bite reactions may appear as itchy, red papules, or wheals. Rarely is the heavily infected & untreated patients’ hair twisted with exudates, making the area more susceptible to a fungus invasion. The outcome is a plica polonica, a foul-smelling mass. Under the clump of matted hair, there are lots of lice & nits.
Nits
By attempting to extract the nit from the hair, you can tell it apart from dried hairspray and hair casts; nits, on the other hand, are firmly linked to the hair. In case the doctor is still unclear, a Wood lamp examination can be done. When illuminated by a Wood lamp, live nits are fluorescent white, while empty nits are luminous grey.
Nits are connected to the hair shafts slightly above the level of the scalp because nits need body heat to incubate their eggs. The separation of nits from the scalp can be used to calculate the length of the infestation because human scalp hair grows at a rate of roughly 10 mm/month (0.37 mm/day). Nits are nonviable empty egg cases that can be detected a few millimeters from the scalp. They suggest persistent infection.
P humanus corporis
Multiple bite-related lesions are found during a physical examination in cases of body louse infection. Erythematous papules that are 2-4 mm in diameter and have an erythematous base characterize uninfected bites. Although bites can occur anywhere on the body, they are most common in the groin, axillae, & trunk (i.e., areas most often covered by clothing). The face, feet, and arms are, therefore, not typically impacted. Except for the edges, body lice typically stay away from the scalp.
It is thought that the presence of maculae cerulea is a pathognomonic sign of a lice infestation. The blue-gray maculae, known as maculae cerulea are actually skin discolorations brought on by bug bites. The change in skin color associated with maculae cerulea is thought to be caused by enzymes that stimulate the breakdown of human bilirubin to biliverdin in the saliva of the louse. There may be severe itching if you have an allergic reaction to a louse bite.
Excoriations may lead to secondary infections. The patient’s clothing must be closely examined for crawling lice and nits in order to diagnose body lice. Common dwelling places are the interior seams of garments worn in the axillae & groin areas. A body louse could occasionally be spotted feeding and creeping on the skin. Although up to 1000 lice can be found in clothing, the average number of body lice per host is around 10.
A person who has had a body louse infection for a long time may develop a condition called vagabond skin. This illness is also known as vagabond sickness. After years of attacks, followed by rubbing & excoriations, the skin becomes thicker and darker. Additionally, it’s crucial to check for any systemic diseases that can be connected to a vector-borne sickness like P corporis.
P pubis
The main sign of pubic lice infection is itching in the areas affected. The presence of pathognomonic maculae cerulea related to bites is another clinical sign of pubic louse infection. It’s possible to find crusts and little areas of blood discoloration on underpants. Usually, pubic hair is the place. The pubic hair typically has noticeable pubic lice & nits all over it. Pubic lice are less mobile than other lice, therefore, you’re more likely to find them in infected areas, latching onto the hairs close to the surface of the skin.
Hair on the axillae, belly, anus, upper arms, chest, eyebrows, eyelashes, and chest. may get infested. Rarely is a location of infestation the facial hair (moustache, beard, eyebrows, and eyelashes). Involvement of the scalp is uncommon and typically limited to the periphery. Involvement of the eyelashes in people without genital participation is uncommon.
The brows & eyelashes are frequently infested in prepubescent children. Not head louse infection, but pubic louse infection is the cause of eyelid nits. Children may contract P pubis infection from an infected parent via sexual contact or as a result of abuse; the child should be checked for symptoms of abuse. Excoriations frequently occur. Additionally, associated with pubic louse infection have been reports of inguinal & axillary lymphadenopathy.
Differential Diagnoses
Pseudonits (hair casts) must be separated from true nit infestation. The inner root sheath of the hair follicle leaves behind ring-shaped remnants known as hair casts. They can travel freely and amorphously along the hair fiber. There are many conditions that might itch the scalp. Erythema & scaling are the symptoms of seborrheic dermatitis. The head, brows, nasolabial folds, and middle chest are all affected.
Inflamed follicular pustules and papules, black crusts, & scarring are the symptoms of acne necrotica. Patients frequently pick at the lesions because it is so itchy. Primitive psocid lice that live free in the environment eat rotting stuff found in old books, leaves, & wildlife habitats. When kids enter an infested library and doghouse, they could spread human scalp infection. Psocids may clearly be identified from Anoplura lice thanks to their large hind legs, powerful jaws, huge heads & long antennae.
The following are additional head louse differential diagnoses:
Delusions
Irregularities in the hair shaft (i.e., trichorrhexis nodosa, monilethrix)
Piedra
Dermatophyte infection
Dried hairspray
Dirt
Desquamated cells
Scabs
Fibers
Dandruff
Body louse infestations might have the following differential diagnoses:
Postinflammatory hyperpigmentation
Impetigo
Xerosis with excoriations
Delusions of parasitosis
Acne
Scabies
Insect Bites
Folliculitis
The following are additional diagnoses for a pubic louse infestation:
Conjunctivitis
Contact dermatitis
Delusions of parasitosis
Folliculitis
Dermatophyte infection
Body lice are typically treated without the use of a pediculicide since better hygiene, such as taking showers and washing clothes in hot water that exceeds 50 C, will usually get rid of the infection. The hot cycle of the washing machine should be used to wash and dry all garments, linens, & towels. Topical corticosteroids & systemic antihistamines can be used to relieve itching. Systemic antibiotics are used appropriately to treat subsequent skin disorders.
Although pediculicides are not necessary for the treatment of body lice infestations, they are frequently used, particularly when body nits and lice are discovered on body hair or when there is a co-infection with pubic lice, head lice, or scabies. The same medications used to treat pubic & head lice are used in these situations, most frequently permethrin lotion administered to the entire body for eight to ten hours.
Additionally, 0.9 percent spinosad topical suspension, 0.5 percent malathion lotion, 1 percent lindane shampoo, and 0.5 percent ivermectin lotion are available as therapies. Due to a number of possibly harmful side effects, such as neurotoxicity & seizures, lindane is not advised as a first-line therapy. Chemical pesticides may need to be applied to the environment in particular situations, including such refugee camps with high populations, in order to stop the spread of illnesses brought on by lice and body lice.
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