Pruritus (itching) is an unpleasant sensation with the need and tendency to scratch. It can present as an independent condition but more often, it is a sign of other diseases. Skin conditions such as eczema, psoriasis, and dermatitis are common, but underlying diseases of the liver and kidneys, thyroid disease, and certain infections can also manifest itching. Other contributing factors are food allergies, drug or any other external agents and dry skin among persons. Conditions like pruritic urticarial papules and plaques of pregnancy (PUPPP) that affect expectant women fall under pregnancy related conditions. 

It is a sensation caused by the stimulation of nerve terminals located in the skin by histamine and other chemicals. Itching sensation can often be chronic and might remain even after the healing of the original condition due to the alterations in the CNS. 

• Prevalence: Pruritus or itch is also a universal complaint and is ranked among the top 50 diseases worldwide, resulting in over 7 million ambulatory visits annually in the United States. Chronic pruritus is a complaint in 8% to 25.5% of the general population over their lifetime, and up to 7% within any given 12-month period. 
• Impact on Quality of Life: Itch in chronic conditions is as bad as the pain, thus the quality of life is lower than in stroke patients. It means it can cause sleep disorders, mood disorders and has a major psychosocial effect. 
• Age: Chronic itch is a common problem observed more commonly in the elderly population constituting 11%. From 5% to 25% of people of 85 years and older. The causes include skin dryness, nerve damage, underlying medical and psychiatric conditions, changes with ageing in skin and perception of pain and possible drug related side effects. 
• Sex: Female patients are also more likely to have itch made worse by psychosomatic reasons and have higher risks when exposed to pruritic situations during pregnancy. Itch is found more frequently in elderly patients with a longer duration of their illness, systemic diseases and multiple comorbidities. 
• Race and Ethnicity: Other studies conducted found out that African Americans and Asians especially women seek care for itch more than other races. Black patients are pruritic more than others because of genetic, immunologic, and structural skin differences. African Americans are found to be more anxious, as are Hispanics and have poorer quality of life because of chronic itch. 

Itch can be categorized into four types: 

• Cutaneous Itch: It is also referred to as pruritoceptive itch and it is a type of itch that originates from skin inflammation. 
• Neuropathic Itch: It starts in the afferent nerve fibres due to conditions such as herpetic neuralgia, multiple sclerosis and space occupying lesions in the brain. 
• Neurogenic Itch: Develops primarily and has no apparent neuronal lesion, frequently related to diseases such as cholestasis. 
• Psychogenic Itch: Observed in parasitophobia if other symptoms might manifest in paranoid conditions.
  Pruritogens act on the itch-specific C fibers that are present in the skin. These are unmyelinated fibers and possess a slow conduction velocity, which is approximately 0.5 m/s. They possess a large number of branches and transmit the impulse to the dorsal horn of the spinal cord. From there, the signals move through the lateral spinothalamic tract then through the thalamus to the somatosensory cortex of the brain where the sensation of itching is felt. 

• Dermatologic Conditions: Eczema, psoriasis, dermatitis, scabies and fungal diseases among them cause skin itching among patients. 
• Systemic Diseases: Liver diseases including cholestasis, kidney diseases, thyroid diseases, hematology diseases are some of the end organ disorders that may lead to pruritus. 
• Neuropathic Causes: In some circumstances, it can also be due to injury of the nerves such as in herpetic neuralgia or diabetic neuropathy. 
• Neurogenic Causes: There are some conditions in which CNS diseases leading to such a condition as, for instance, certain lesions of the brain or cholestasis, do not result from direct damage to neurons but can still produce itchy sensations. 
• Psychogenic Factors: Some diseases that affect the patient’s mental health can cause pruritus, for example, delusional disorder or obsessive-compulsive disorder. 

• Underlying Cause: Other factors include the severity and management of the primary disease leading to pruritus, such as eczema or liver diseases. Inpatient and outpatient treatment may help if the cause of the problem is treated in time. 
• Duration and Chronicity: It has also been observed that acute pruritus has a relatively favorable outcome compared to chronic pruritus. Itching described as persistent, long-term, or recurrent may be more severe and may need different approaches to treatment for more than 6 weeks’ duration. 
• Response to Treatment: Some of the interventions include topical treatments, antihistamines or systemic interventions, are determinants of the prognosis. Effective treatment and management of the condition can result in improved prognosis of the disease. 
• Patient Characteristics: Some factors that affect prognosis include age and presence of other illnesses. Patients who have other diseases or are of elder age can experience more severe or long-lasting pruritus. 
• Psychological Impact: Stress, anxiety, and depression affect pruritus and its treatment outcomes thus should be evaluated and well managed in patients with pruritus. Manages mental health prognosis hence improve the overall disease prognosis. 

Age Groups: 

• Children: Usually seen in atopic dermatitis, contact dermatitis, and viral exanthem. Some children may develop rashes on the skin and they can scratch themselves and end up developing skin ulcers or infections. 
• Adults: Most associated with diseases such as psoriasis, chronic dermatitis, and with various systemic diseases of the liver or kidneys. Adults can also develop itch from allergy or as a side effect from drugs they might be taking. 
• Elderly: In elderly people, pruritus is often accompanied by xerosis, changes in the skin’s barrier properties related to aging, and systemic diseases, such as chronic kidney disease or diabetes mellitus. It also involves drugs and neuropathies that may further complicate the situation for the elderly individuals. 

General Inspection: Check the texture and the color of the skin and presence of inflammation. An assessment should be made of any primary skin lesions (rash, plaques, wheals, etc) and secondary changes (excoriations, lichenification, infection, etc). Observe where itching occurs, the areas of skin, swollen or inflamed, and any areas that seem more sensitive than others. For instance, eczema usually favors the flexural surfaces while psoriasis may commonly develop in the extensor surfaces. 

Dermatological Examination 

• Primary Lesions: It should be a direct relationship of primary lesions like papules, vesicles or urticaria if present. 
• Secondary Lesions: There may be secondary lesions such as crusts, scales or excoriations because of scratching. 
• Texture and Temperature: Evaluate the skin condition to determine whether it is thickened or smooth and whether it is warm or cool to touch in the affected areas. 

• Skin Conditions: Some dermatological illnesses that cause skin rashes include eczema, psoriasis, and hives. These include localized skin infections, which are caused by constant scratching. 
• Systemic Diseases: Conditions such as liver disease (e.g. cholestasis), kidney pathology, thyroid abnormalities, or hematological disorders can be linked to chronic itching. 
• Neurological Conditions: Neuropathic itch can be observed in patients with multiple sclerosis, diabetic neuropathy and other diseases.

• Acute Pruritus: Usually does not exceed 6 weeks of duration and can be caused by acute allergic responses, infections, or contact dermatitis.  
• Chronic Pruritus: Usually lasts more than 6 weeks and may be linked to chronic skin disorders, other body diseases, or persistent causes of skin irritation.  

Non-Pharmacological Approaches 

• Skin Care: Massage the skin to maintain its moisture using appropriate topical agents throughout the day. 
• Behavioral Interventions: Direct patients not to scrub, apply ice packs and take short cool showers and manage stress. 
• Environmental Modifications: Try using a humidifier, avoiding specific allergens, and wearing breathable fabrics. 

Pharmacological Treatments 

• Detoxifying Agents: Activated charcoal can be used for renal pruritus, but the exact working of this agent has not been determined so far.

Topical Agents: 

• Capsaicin: It has a localized anti-pruritic effect by depleting substance P from sensory neurons present in the affected area. 
• Aspirin: It should be noted that a 3% topical solution is beneficial for chronic localized itching. 
• Salicylic Acid: May help decrease itching when applied together with topical immunomodulators. 

Immunomodulatory Agents: 

• Thalidomide: It lowers itching through the inhibition of T helper cells and the secretion of TNF-alpha but comes with serious side effects.

Bile Acid Lowering Agents: 

• Cholestyramine: Appears to tie down bile acids and is helpful in treatment of pruritus of bile disease and liver cholestasis.
• Ursodeoxycholic Acid: Reduces inflammation and the reabsorption of bile in the liver, useful in treating ICP.

Antidepressant Agents: 

• Paroxetine: An SSRI that fighting itching, onset time of action is within 3-5 days. 
• Doxepin: A tricyclic antidepressant, which also has antihistamine property; it is used at night due to its side effect of sedation.
• Opioid Receptor Antagonists: Naloxone and naltrexone are used to treat pruritus associated with cholestasis and uremia, Nonetheless, naltrexone is effective in the treatment of uremic pruritus with contradicting outcomes. 
• Anion Exchange Resin: Colestipol effective in the management of biliary pruritus, may act by reducing bile salts. 

Procedural Interventions 

• Phototherapy: Also ranges from UVB, and PUVA for different forms of pruritus.
• Acupuncture: May help in decreasing pruritus to some extent in specific conditions. 
• Neurolytic Blocks: It is utilized for the persistent pruritus by performing the nerve blocks or ablations. 
• Cryotherapy: Has proved useful in the management of pruritus in certain parts of the body. 

Phases of Management 

• Identification and Diagnosis: Doctor should take time and examine patient’s medical history, as well as carry out tests to determine the causes of the ailments. 
• Elimination of Underlying Causes: As best or avoid factors such as eczema, psoriasis, or medicine. 
• Symptomatic Relief: Manage symptoms with topical agents, including moisturizers, corticosteroids, and antihistamines and oral agents such as antihistamines and corticosteroids when necessary. 

• Skin Care: Emollients should be applied at frequent intervals to ensure proper skin moisturizing, sticking to products that are not likely to cause skin inflammation, and observing good skin care techniques. 
• Behavioral Interventions: Education regarding not scratching the skin, using methods for skin cooling (for example, cold compresses), and stress reduction. 
• Environmental Modifications: Using a humidifier, not touching or going near anything that has triggered an episode, and wearing free, comfortable clothes. 

Dermatology, General

• Activated charcoal (Charcodote): It is the most frequent type of treatment for renal pruritus that can be prescribed as the first-line therapy. Although its precise mode of action is not well defined, it behavioural action may be explained by the fact that it reacts with a yet undiscovered receptor that stimulates itching. In some formulations, sorbitol and flavouring agents are added to enhance the taste of the medicine. 

Dermatology, General

• Capsaicin topical: It is a secondary metabolite that belong to the compounds that are found in plants within Solanacea family. It is achieved through the depletion of substance P from peripheral sensory neurones, which reduces the effect of pain and itch stimuli, thereby decreasing the sensitivity of the skin and joints. This treatment is used when the pruritus is localized. 
• Aspirin: A topical preparation in a 3% acetyl salicylic acid solution which was used in chronic localized itching was shown to have reduced it effectively.
  
• Salicylic Acid: The use of salicylic acid was also observed to have potential in reducing itching which may be due to its combination with topical immunomodulators like tacrolimus and pimecrolimus. 
• Menthol and Phenol: Aqueous cream consisting of 1-2% menthol and phenol are useful in producing a cooling sensation that can help to block the feeling of itching by blocking the nerve impulses and relay cooling sensation instead. 

Dermatology, General

• Thalidomide: It is thought to suppress T helper cells and decrease the release of TNF-alpha which may assist in decreasing itching. It also has a substantial centrally mediated depressant effect which could help with pruritus. Efficient treatment options that can be considered before using Thalidomide include side effects associated that make it contraindicated for first-time usage. 

Dermatology, General

• Cholestyramine: It is an anion exchange resin that forms complexes with bile steroids within the gastrointestinal area thus interrupting the enterohepatic circulation. It is mainly indicated for the treatment of raised cholesterol levels, but it can also be used in the treatment of pruritus in hepatic cholestasis when there is adequate biliary pigmentation. Because of its relative inexpensiveness and effectiveness within 1-3 weeks, hepatic cholestasis can be treated by this treatment option at the initial stage.  
• Ursodeoxycholic Acid/Ursodiol: It is a water-soluble bile acid which alter the pattern and content of total bile acids and increase the elimination of the more lipid soluble bile acids. It decreases inflammation within hepatocyte cells by decreasing the reabsorption of the hydrophobic bile acid in the terminal ileum and perhaps in the hepatocytes. Ursodiol is effective in the treatment of intrahepatic cholestasis of pregnancy because it improves laboratory values and has positive benefits on fetal exposure to bile acids resulting into decreased fetal morbidity and mortality. 

Dermatology, General

• Paroxetine: It is a potent or highly potent serotonergic re-uptake inhibitor better described as a selective serotonin re-uptake inhibitor (SSRI). It is still not clear how it works to reduce itching, but it has an effect within 3 to 5 days, and this may only last for 4-6 weeks. 
• Doxepin: It belongs to the tricyclic antidepressants although its main use today is in urticaria where due to its potent H1 antihistamine activity. However, it is commonly associated with marked sedation and anticholinergic side effects. Due to its sedative effects, doxepin is also suitable for those who must take a tablet before going to bed and have pruritus. 

Dermatology, General

Randomised controlled trials have shown that opioid receptor antagonists including naloxone and naltrexone are useful in treatment of pruritus in cholestatic, uraemic, and skin diseases. However, research studies regarding the effectiveness of naltrexone in patients with uremic pruritus has had mixed findings. 

Dermatology, General

• Cholestyramine: Oral anion exchange resin that has been shown to be useful in the management of biliary pruritus is Cholestyramine. Despite its precise mode of action is not fully apprehended, it is suspected to have its connection with the biliary salts elimination. 

Dermatology, General

Phototherapy: 

• UVB Phototherapy: Suitable for different categories of patients and specifically for patients diagnosed with CKD. 
• PUVA (Psoralen + UVA) Therapy: It is prescribed for adults and children with severe atopic dermatitis or psoriasis. 
• Acupuncture: Some reviews presented a possibility of using acupuncture as an effective method of reducing pruritus in particular diseases. 
• Neurolytic Blocks: For uncontrolled pruritus nerve blocks or ablations might be used. 
• Cryotherapy: It is applied in the treatment of pruritus that affects localized areas of the body skin especially where there are some skin diseases. 
• Behavioral Therapy: Psychotherapy plays a role in treating the psychological aspects of chronic itching, and cognitive behavioral therapy is effective. 

Dermatology, General

Identification and Diagnosis: Check the patient’s past medical record, recent changes in the patient’s medication, presence of allergic reactions, or the presence of chronic illnesses. Other diagnostic tests to be conducted to determine underlying causative factors include skin biopsy, blood test, or allergy test. 

Elimination of Underlying Causes: Investigate and manage factors such as eczema, psoriasis, or liver disease that are related to the skin condition. In case the causes are medicine or allergens, avoid the use of the medicine or be careful when exposed to the allergen. 

Symptomatic Relief 

• Topical Treatments: Apply lotions to decrease the degree of itching and inflammation that the patient may be experiencing and use topical corticosteroids and antihistamines. 
• Oral Medications: Try using antihistamines for an instance or the common oral corticosteroids when the symptoms are more severe for an instance. 
• Lifestyle and Home Remedies: Use moisturizers; do not have hot showers and do not use soap on your skin. Avoid products that cause itching, including types of cloth, soap or washing powder that one uses. 
• Follow-Up and Adjustments: Re-evaluate the patient’s responses to the administered therapies and doses and alter them, accordingly. If pruritus continues to be a problem, the patient should be referred to a dermatologist or other appropriate consultant.