What are the causes and treatments of anal pruritus?

From the Guidelines

Anal pruritus, or itching around the anus, is commonly caused by poor hygiene, moisture, certain foods, skin conditions, infections, or medications, and the most effective treatment approach involves a combination of proper hygiene, dietary changes, and targeted therapies, as recommended by the British Association of Dermatologists' guidelines for the investigation and management of generalized pruritus in adults without an underlying dermatosis, 2018 1. To treat anal pruritus, it is essential to keep the area clean and dry by gently washing with mild soap and water after bowel movements, then thoroughly drying. Avoiding scratching, wearing loose cotton underwear, and using unscented toilet paper can also help alleviate symptoms. Dietary changes, such as reducing spicy foods, caffeine, alcohol, and citrus fruits, may also be beneficial. Over-the-counter treatments, including hydrocortisone cream (0.5-1%) applied sparingly twice daily for up to two weeks to reduce inflammation, zinc oxide ointment as a barrier, or witch hazel pads to soothe the area, can be effective. Antifungal creams like clotrimazole can treat fungal infections, while prescription medications, such as stronger corticosteroids or antihistamines like diphenhydramine (25-50mg) at bedtime for nighttime itching, may be necessary for persistent symptoms. If parasites like pinworms are suspected, medications such as mebendazole (100mg once, repeated after two weeks) may be prescribed. It is crucial to break the cycle of itching and irritation by maintaining proper hygiene and using appropriate treatments, as anal pruritus often results from a cycle where itching damages skin, causing more irritation and further itching. Additionally, the British Association of Dermatologists' guidelines recommend considering the patient's overall health status, drug history, family history, and psychosocial issues when diagnosing and managing generalized pruritus, and referring patients to secondary care if there is diagnostic doubt or if symptoms are distressing despite primary care management 1. The guidelines also suggest that liver transplantation may be effective for patients with cholestatic liver diseases who are resistant to other treatments, as recommended by the EASL clinical practice guidelines for the management of cholestatic liver diseases 1. In terms of specific treatments, the guidelines recommend cholestyramine as a first-line treatment for pruritus, followed by rifampicin, naltrexone, and sertraline as second-, third-, and fourth-line treatments, respectively 1. Overall, a comprehensive approach to treating anal pruritus involves addressing the underlying causes, maintaining proper hygiene, and using targeted therapies to alleviate symptoms and improve quality of life. Some key points to consider when treating anal pruritus include:

• Keeping the area clean and dry
• Avoiding scratching and wearing loose cotton underwear
• Using dietary changes and over-the-counter treatments to alleviate symptoms
• Considering prescription medications and antifungal creams for persistent symptoms
• Breaking the cycle of itching and irritation through proper hygiene and treatment
• Referring patients to secondary care if necessary
• Considering liver transplantation as a last resort for patients with cholestatic liver diseases.

From the FDA Drug Label

Uses temporarily relieves itching associated with minor skin irritations, inflammation, and rashes due to: eczema psoriasis poison ivy, oak, sumac insect bites detergents jewelry cosmetics soaps seborrheic dermatitis temporarily relieves external anal and genital itching Directions for itching of skin irritation, inflammation, and rashes: adults and children 2 years of age and older: apply to affected area not more than 3 to 4 times daily The causes of anal pruritus include:

• Eczema
• Psoriasis
• Insect bites
• Irritation from detergents, jewelry, cosmetics, or soaps
• Seborrheic dermatitis The treatments for anal pruritus include:
• Applying hydrocortisone to the affected area not more than 3 to 4 times daily
• Cleaning the affected area with mild soap and warm water and rinsing thoroughly
• Gently drying the area by patting or blotting with toilet tissue or a soft cloth before applying hydrocortisone 2 2

From the Research

Causes of Anal Pruritus

• Anal pruritus can be associated with idiopathic and secondary causes, such as anorectal diseases, cancer (anal or colorectal), dermatological and sexually transmitted diseases, fungal infections, and systemic diseases 3
• Pruritus ani can be caused by dermatologic and systemic conditions, and an exposure history may reveal symptom triggers 4
• A thorough history and physical examination are essential in view of multiple possible causes of anal pruritus, with a focus on the perianal region 5
• Common inciting agents and local irritants, such as certain foods and soaps, can contribute to anal pruritus 6

Treatments for Anal Pruritus

• The treatment normally consists of a triple approach: proper hygiene, elimination of irritants, and skin care and protection 3
• Topical therapies, such as steroids, capsaicin, tacrolimus, and methylene blue intradermal injections, have been described as possible treatments 3, 5, 6
• General management includes trigger avoidance, liberal emollient use, limiting water exposure, and administration of oral antihistamines and topical corticosteroids 4
• For intractable cases, intradermal methylene blue injection might give a long-lasting symptom relief 5, 6
• Dietary modifications, such as increasing fiber intake and avoiding certain foods, can also help alleviate symptoms 5, 6