Onychomycosis, also known as toenail fungus, is a fungal infection that affects the nails of the toes and fingers. It is a common condition caused by various fungi, including dermatophytes, yeasts, and molds. Onychomycosis can affect one or more nails and is more common in toenails than in fingernails.
Symptoms of onychomycosis include thickened, discolored, and brittle nails that may separate from the nail bed. The nail may also have a foul-smelling odor. Onychomycosis is common in individuals with diabetes, immune-compromised conditions such as HIV, AIDS, cancer, poor circulation, and sweaty feet or tight-fitting shoes.
Epidemiology
The global prevalence of onychomycosis is challenging to determine because it is not a reportable condition in many countries. However, it is estimated that onychomycosis affects about 10% of the general population worldwide.
The prevalence may be higher in certain populations, such as older adults, people with diabetes or other medical conditions that affect the immune system, and in individuals with a history of athlete’s foot or other fungal infections and in people who have poor hygiene or wear tight-fitting shoes or socks.
The condition is more common in men than in women and is more common in toenails than in fingernails. Onychomycosis is more common in toenails than in fingernails and is more likely to affect people with damaged nails or who have a history of nail infections. It is also common in people who have poor hygiene or do not take good care of their nails.
Anatomy
Pathophysiology
In most cases, onychomycosis begins with an asymptomatic, athlete’s foot or dry hyperkeratotic tinea pedis. Over time, the heat, damp environment of shoes and the microtrauma caused by strain on the nail unit can weaken the hyponychial seal, allowing the fungi to enter the nail bed and infect the nails. Exposure to water in wet work can also damage the nails and make them more susceptible to infection.
Dermatophytes, one of the types of fungi that can cause onychomycosis, only grow on the keratin of dead skin cells in the nails, skin, and hair. In the feet, dermatophytes produce enzymes called keratinases that set out the infection between the toes and spread to the soles of the feet. From there, the infection gradually extends to the distal hyponychial space of the nails and, eventually, to the nail bed. As the infection progresses, it may cause the nails to become thickened, discolored, and brittle, and separate from the nail bed.
Histologically, the acute phase of onychomycosis is characterized by acanthosis, spongiosis papillomatosis with edema, and hyperkeratosis, which are similar to the pathology of psoriasis. An inflammatory infiltrate also develops in response to the infection. The nail matrix can also be affected by the infection, as the nail bed becomes thickened and hyperkeratotic to shed the fungus. The fungus may invade the overlying nail plate, causing it to become elevated and misaligned.
At the chronic stage of the infection, known as total dystrophic onychomycosis (TDO), there is a large amount of compact hyperkeratosis, acanthosis, hypergranulosis, and papillomatosis, as well as a sparse perivascular infiltrate. Dermatophytosis and subungual seromas may also occur. High levels of cytokines interleukin-6 and interleukin-10 and human beta defensin-2 fibers have been found in the nail bed and plate of infected nails.
Etiology
Onychomycosis, or toenail fungus, is most commonly caused by the fungus Trichophyton rubrum, but other dermatophytes, such as Trichophyton mentagrophytes and Epidermophyton floccosum, can also cause it. Dermatophytes are responsible for about 90% of toenail onychomycosis and 50% of fingernail onychomycosis. Candida albicans, a type of yeast, is a less common cause of onychomycosis and is more commonly found in fingernails.
Nondermatophytic mold onychomycosis, primarily found in toenails, is caused by saprophytic molds, such as Fusarium, Aspergillus, Acremonium, Scytalidium, Scopulariopsis brevicaulis, and accounts for about 8% of nail infections. Onychomycosis is more likely to occur in people with damaged nails or a history of nail infections. It is also more common in people with diabetes or other medical conditions that affect the immune system and those who frequently wear tight-fitting shoes or have sweaty feet.
Onychomycosis may also occur in people who have poor hygiene or do not take good care of their nails. The fungi that cause onychomycosis can be transmitted through direct contact with infected nails or contaminated objects, such as nail clippers or foot baths. It is also possible to contract onychomycosis from walking barefoot in public areas, such as swimming pools or showers, where the fungi can thrive in warm, moist environments.
Genetics
Prognostic Factors
The prognosis for onychomycosis depends on the infection’s severity and the treatment’s effectiveness. In some cases, the infection may clear up quickly with proper treatment, while it may take longer to resolve in other cases.
If left untreated, onychomycosis can lead to further complications, such as spreading the infection to other nails or skin or developing ingrown toenails. It is important to seek treatment as soon as possible to improve the prognosis and follow the prescribed treatment plan.
Clinical History
Clinical History
The duration, progression, and previous treatment outcomes is important in nail disease. Medication history, particularly for suspected onychomycosis, should be noted, as it may affect the use of systemic antifungals.
It is also essential to consider medical history, travel history, and social habits, such as a history of hepatitis or travel to areas with high rates of hepatitis, alcohol use, recreational activities, and any associated skin conditions such as tinea manuum, cruris, or psoriasis.
Pedal onychomycosis affecting the toenails is typically characterized by thickened, discolored nails, with the great toenails most commonly affected. Many patients also have mild, dry, scaly skin on the feet.
Physical Examination
Physical Examination
Onychomycosis can be classified into different subtypes based on the location and appearance of the infection. The most common subtype is distal lateral subungual onychomycosis, which affects the end of the nail and presents with partial separation from the nail bed and thickened skin under the nail.
White superficial onychomycosis is less common and appears as white, chalky deposits on the surface of the nail that can be easily removed. The rarest subtype is proximal subungual onychomycosis, which develops at the base of the nail and is often seen in people with AIDS. The most advanced stage of onychomycosis is characterized by thick skin under the nail, severe damage to the nail plate, and ridging of the nail bed.
This stage is the most challenging to treat and also poses a significant risk of complications, including ulcerations under the nail, bacterial infections, and even gangrene in individuals with poor blood circulation. Knowing the subtype of onychomycosis can help guide treatment and improve outcomes.
Age group
Associated comorbidity
Associated activity
Acuity of presentation
Differential Diagnoses
Differential Diagnoses
Hypothyroidism
Contact dermatitis
Adverse drug reaction
Nail psoriasis
Nail malignancy
Yellow nail syndrome
Laboratory Studies
Imaging Studies
Procedures
Histologic Findings
Staging
Treatment Paradigm
Treatment options for onychomycosis include systemic antifungal medications. Oral antifungal therapy is recommended for moderate to severe cases, especially for patients with diabetes. Combining topical treatments, regular nail trimming, or chemical removal of the infected nail can also improve outcomes. For mild to moderate cases, newer topical antifungal treatments are available as an alternative to systemic antifungals.
When considering oral antifungal therapy for onychomycosis, it is essential to evaluate the patient’s medical history, including alcohol use disorder and potential hepatitis. Before starting treatment, it is recommended to perform liver function tests, such as alanine aminotransferase and aspartate aminotransferase, to establish a baseline.
Furthermore, if the patient has a history of living in areas where hepatitis is prevalent, adding a screening panel for hepatitis may be recommended. Monitoring liver function tests at five weeks post-treatment can help detect any uncommon reactions. The medication should be discontinued and re-evaluated if any abnormal values are found. Additionally, it is important to consider any concurrent medications that may interact with the oral antifungal.
Indicated for the treatment of toenail and fingernail having dermatophytes (tinea unguium)
250 mg orally once daily for 6 weeks to treat fingernail and 12 weeks to treat toenail
Dose Modifications
The drug is not recommended in the case of renal impairment when CrCl is less than 50 ml/min
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References
https://www.ncbi.nlm.nih.gov/books/NBK441853/
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Onychomycosis, also known as toenail fungus, is a fungal infection that affects the nails of the toes and fingers. It is a common condition caused by various fungi, including dermatophytes, yeasts, and molds. Onychomycosis can affect one or more nails and is more common in toenails than in fingernails.
Symptoms of onychomycosis include thickened, discolored, and brittle nails that may separate from the nail bed. The nail may also have a foul-smelling odor. Onychomycosis is common in individuals with diabetes, immune-compromised conditions such as HIV, AIDS, cancer, poor circulation, and sweaty feet or tight-fitting shoes.
The global prevalence of onychomycosis is challenging to determine because it is not a reportable condition in many countries. However, it is estimated that onychomycosis affects about 10% of the general population worldwide.
The prevalence may be higher in certain populations, such as older adults, people with diabetes or other medical conditions that affect the immune system, and in individuals with a history of athlete’s foot or other fungal infections and in people who have poor hygiene or wear tight-fitting shoes or socks.
The condition is more common in men than in women and is more common in toenails than in fingernails. Onychomycosis is more common in toenails than in fingernails and is more likely to affect people with damaged nails or who have a history of nail infections. It is also common in people who have poor hygiene or do not take good care of their nails.
In most cases, onychomycosis begins with an asymptomatic, athlete’s foot or dry hyperkeratotic tinea pedis. Over time, the heat, damp environment of shoes and the microtrauma caused by strain on the nail unit can weaken the hyponychial seal, allowing the fungi to enter the nail bed and infect the nails. Exposure to water in wet work can also damage the nails and make them more susceptible to infection.
Dermatophytes, one of the types of fungi that can cause onychomycosis, only grow on the keratin of dead skin cells in the nails, skin, and hair. In the feet, dermatophytes produce enzymes called keratinases that set out the infection between the toes and spread to the soles of the feet. From there, the infection gradually extends to the distal hyponychial space of the nails and, eventually, to the nail bed. As the infection progresses, it may cause the nails to become thickened, discolored, and brittle, and separate from the nail bed.
Histologically, the acute phase of onychomycosis is characterized by acanthosis, spongiosis papillomatosis with edema, and hyperkeratosis, which are similar to the pathology of psoriasis. An inflammatory infiltrate also develops in response to the infection. The nail matrix can also be affected by the infection, as the nail bed becomes thickened and hyperkeratotic to shed the fungus. The fungus may invade the overlying nail plate, causing it to become elevated and misaligned.
At the chronic stage of the infection, known as total dystrophic onychomycosis (TDO), there is a large amount of compact hyperkeratosis, acanthosis, hypergranulosis, and papillomatosis, as well as a sparse perivascular infiltrate. Dermatophytosis and subungual seromas may also occur. High levels of cytokines interleukin-6 and interleukin-10 and human beta defensin-2 fibers have been found in the nail bed and plate of infected nails.
Onychomycosis, or toenail fungus, is most commonly caused by the fungus Trichophyton rubrum, but other dermatophytes, such as Trichophyton mentagrophytes and Epidermophyton floccosum, can also cause it. Dermatophytes are responsible for about 90% of toenail onychomycosis and 50% of fingernail onychomycosis. Candida albicans, a type of yeast, is a less common cause of onychomycosis and is more commonly found in fingernails.
Nondermatophytic mold onychomycosis, primarily found in toenails, is caused by saprophytic molds, such as Fusarium, Aspergillus, Acremonium, Scytalidium, Scopulariopsis brevicaulis, and accounts for about 8% of nail infections. Onychomycosis is more likely to occur in people with damaged nails or a history of nail infections. It is also more common in people with diabetes or other medical conditions that affect the immune system and those who frequently wear tight-fitting shoes or have sweaty feet.
Onychomycosis may also occur in people who have poor hygiene or do not take good care of their nails. The fungi that cause onychomycosis can be transmitted through direct contact with infected nails or contaminated objects, such as nail clippers or foot baths. It is also possible to contract onychomycosis from walking barefoot in public areas, such as swimming pools or showers, where the fungi can thrive in warm, moist environments.
The prognosis for onychomycosis depends on the infection’s severity and the treatment’s effectiveness. In some cases, the infection may clear up quickly with proper treatment, while it may take longer to resolve in other cases.
If left untreated, onychomycosis can lead to further complications, such as spreading the infection to other nails or skin or developing ingrown toenails. It is important to seek treatment as soon as possible to improve the prognosis and follow the prescribed treatment plan.
Clinical History
The duration, progression, and previous treatment outcomes is important in nail disease. Medication history, particularly for suspected onychomycosis, should be noted, as it may affect the use of systemic antifungals.
It is also essential to consider medical history, travel history, and social habits, such as a history of hepatitis or travel to areas with high rates of hepatitis, alcohol use, recreational activities, and any associated skin conditions such as tinea manuum, cruris, or psoriasis.
Pedal onychomycosis affecting the toenails is typically characterized by thickened, discolored nails, with the great toenails most commonly affected. Many patients also have mild, dry, scaly skin on the feet.
Physical Examination
Onychomycosis can be classified into different subtypes based on the location and appearance of the infection. The most common subtype is distal lateral subungual onychomycosis, which affects the end of the nail and presents with partial separation from the nail bed and thickened skin under the nail.
White superficial onychomycosis is less common and appears as white, chalky deposits on the surface of the nail that can be easily removed. The rarest subtype is proximal subungual onychomycosis, which develops at the base of the nail and is often seen in people with AIDS. The most advanced stage of onychomycosis is characterized by thick skin under the nail, severe damage to the nail plate, and ridging of the nail bed.
This stage is the most challenging to treat and also poses a significant risk of complications, including ulcerations under the nail, bacterial infections, and even gangrene in individuals with poor blood circulation. Knowing the subtype of onychomycosis can help guide treatment and improve outcomes.
Differential Diagnoses
Hypothyroidism
Contact dermatitis
Adverse drug reaction
Nail psoriasis
Nail malignancy
Yellow nail syndrome
Treatment options for onychomycosis include systemic antifungal medications. Oral antifungal therapy is recommended for moderate to severe cases, especially for patients with diabetes. Combining topical treatments, regular nail trimming, or chemical removal of the infected nail can also improve outcomes. For mild to moderate cases, newer topical antifungal treatments are available as an alternative to systemic antifungals.
When considering oral antifungal therapy for onychomycosis, it is essential to evaluate the patient’s medical history, including alcohol use disorder and potential hepatitis. Before starting treatment, it is recommended to perform liver function tests, such as alanine aminotransferase and aspartate aminotransferase, to establish a baseline.
Furthermore, if the patient has a history of living in areas where hepatitis is prevalent, adding a screening panel for hepatitis may be recommended. Monitoring liver function tests at five weeks post-treatment can help detect any uncommon reactions. The medication should be discontinued and re-evaluated if any abnormal values are found. Additionally, it is important to consider any concurrent medications that may interact with the oral antifungal.
Indicated for the treatment of toenail and fingernail having dermatophytes (tinea unguium)
250 mg orally once daily for 6 weeks to treat fingernail and 12 weeks to treat toenail
Dose Modifications
The drug is not recommended in the case of renal impairment when CrCl is less than 50 ml/min
https://www.ncbi.nlm.nih.gov/books/NBK441853/
medtigo
Onychomycosis
Updated :
January 16, 2023
Onychomycosis, also known as toenail fungus, is a fungal infection that affects the nails of the toes and fingers. It is a common condition caused by various fungi, including dermatophytes, yeasts, and molds. Onychomycosis can affect one or more nails and is more common in toenails than in fingernails.
Symptoms of onychomycosis include thickened, discolored, and brittle nails that may separate from the nail bed. The nail may also have a foul-smelling odor. Onychomycosis is common in individuals with diabetes, immune-compromised conditions such as HIV, AIDS, cancer, poor circulation, and sweaty feet or tight-fitting shoes.
The global prevalence of onychomycosis is challenging to determine because it is not a reportable condition in many countries. However, it is estimated that onychomycosis affects about 10% of the general population worldwide.
The prevalence may be higher in certain populations, such as older adults, people with diabetes or other medical conditions that affect the immune system, and in individuals with a history of athlete’s foot or other fungal infections and in people who have poor hygiene or wear tight-fitting shoes or socks.
The condition is more common in men than in women and is more common in toenails than in fingernails. Onychomycosis is more common in toenails than in fingernails and is more likely to affect people with damaged nails or who have a history of nail infections. It is also common in people who have poor hygiene or do not take good care of their nails.
In most cases, onychomycosis begins with an asymptomatic, athlete’s foot or dry hyperkeratotic tinea pedis. Over time, the heat, damp environment of shoes and the microtrauma caused by strain on the nail unit can weaken the hyponychial seal, allowing the fungi to enter the nail bed and infect the nails. Exposure to water in wet work can also damage the nails and make them more susceptible to infection.
Dermatophytes, one of the types of fungi that can cause onychomycosis, only grow on the keratin of dead skin cells in the nails, skin, and hair. In the feet, dermatophytes produce enzymes called keratinases that set out the infection between the toes and spread to the soles of the feet. From there, the infection gradually extends to the distal hyponychial space of the nails and, eventually, to the nail bed. As the infection progresses, it may cause the nails to become thickened, discolored, and brittle, and separate from the nail bed.
Histologically, the acute phase of onychomycosis is characterized by acanthosis, spongiosis papillomatosis with edema, and hyperkeratosis, which are similar to the pathology of psoriasis. An inflammatory infiltrate also develops in response to the infection. The nail matrix can also be affected by the infection, as the nail bed becomes thickened and hyperkeratotic to shed the fungus. The fungus may invade the overlying nail plate, causing it to become elevated and misaligned.
At the chronic stage of the infection, known as total dystrophic onychomycosis (TDO), there is a large amount of compact hyperkeratosis, acanthosis, hypergranulosis, and papillomatosis, as well as a sparse perivascular infiltrate. Dermatophytosis and subungual seromas may also occur. High levels of cytokines interleukin-6 and interleukin-10 and human beta defensin-2 fibers have been found in the nail bed and plate of infected nails.
Onychomycosis, or toenail fungus, is most commonly caused by the fungus Trichophyton rubrum, but other dermatophytes, such as Trichophyton mentagrophytes and Epidermophyton floccosum, can also cause it. Dermatophytes are responsible for about 90% of toenail onychomycosis and 50% of fingernail onychomycosis. Candida albicans, a type of yeast, is a less common cause of onychomycosis and is more commonly found in fingernails.
Nondermatophytic mold onychomycosis, primarily found in toenails, is caused by saprophytic molds, such as Fusarium, Aspergillus, Acremonium, Scytalidium, Scopulariopsis brevicaulis, and accounts for about 8% of nail infections. Onychomycosis is more likely to occur in people with damaged nails or a history of nail infections. It is also more common in people with diabetes or other medical conditions that affect the immune system and those who frequently wear tight-fitting shoes or have sweaty feet.
Onychomycosis may also occur in people who have poor hygiene or do not take good care of their nails. The fungi that cause onychomycosis can be transmitted through direct contact with infected nails or contaminated objects, such as nail clippers or foot baths. It is also possible to contract onychomycosis from walking barefoot in public areas, such as swimming pools or showers, where the fungi can thrive in warm, moist environments.
The prognosis for onychomycosis depends on the infection’s severity and the treatment’s effectiveness. In some cases, the infection may clear up quickly with proper treatment, while it may take longer to resolve in other cases.
If left untreated, onychomycosis can lead to further complications, such as spreading the infection to other nails or skin or developing ingrown toenails. It is important to seek treatment as soon as possible to improve the prognosis and follow the prescribed treatment plan.
Clinical History
The duration, progression, and previous treatment outcomes is important in nail disease. Medication history, particularly for suspected onychomycosis, should be noted, as it may affect the use of systemic antifungals.
It is also essential to consider medical history, travel history, and social habits, such as a history of hepatitis or travel to areas with high rates of hepatitis, alcohol use, recreational activities, and any associated skin conditions such as tinea manuum, cruris, or psoriasis.
Pedal onychomycosis affecting the toenails is typically characterized by thickened, discolored nails, with the great toenails most commonly affected. Many patients also have mild, dry, scaly skin on the feet.
Physical Examination
Onychomycosis can be classified into different subtypes based on the location and appearance of the infection. The most common subtype is distal lateral subungual onychomycosis, which affects the end of the nail and presents with partial separation from the nail bed and thickened skin under the nail.
White superficial onychomycosis is less common and appears as white, chalky deposits on the surface of the nail that can be easily removed. The rarest subtype is proximal subungual onychomycosis, which develops at the base of the nail and is often seen in people with AIDS. The most advanced stage of onychomycosis is characterized by thick skin under the nail, severe damage to the nail plate, and ridging of the nail bed.
This stage is the most challenging to treat and also poses a significant risk of complications, including ulcerations under the nail, bacterial infections, and even gangrene in individuals with poor blood circulation. Knowing the subtype of onychomycosis can help guide treatment and improve outcomes.
Differential Diagnoses
Hypothyroidism
Contact dermatitis
Adverse drug reaction
Nail psoriasis
Nail malignancy
Yellow nail syndrome
Treatment options for onychomycosis include systemic antifungal medications. Oral antifungal therapy is recommended for moderate to severe cases, especially for patients with diabetes. Combining topical treatments, regular nail trimming, or chemical removal of the infected nail can also improve outcomes. For mild to moderate cases, newer topical antifungal treatments are available as an alternative to systemic antifungals.
When considering oral antifungal therapy for onychomycosis, it is essential to evaluate the patient’s medical history, including alcohol use disorder and potential hepatitis. Before starting treatment, it is recommended to perform liver function tests, such as alanine aminotransferase and aspartate aminotransferase, to establish a baseline.
Furthermore, if the patient has a history of living in areas where hepatitis is prevalent, adding a screening panel for hepatitis may be recommended. Monitoring liver function tests at five weeks post-treatment can help detect any uncommon reactions. The medication should be discontinued and re-evaluated if any abnormal values are found. Additionally, it is important to consider any concurrent medications that may interact with the oral antifungal.
https://www.ncbi.nlm.nih.gov/books/NBK441853/
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