Pruritus Ani

Intense chronic itching in the anal region.

Pruritus ani is a common problem with many causes. The most common exogenous causes are using harsh soaps, using sensitizing perfumes or deodorizers, wiping excessively with toilet paper, and wearing synthetic underwear or tight, warm clothing, which promotes sweating. Other causes include fungal diseases (eg, epidermophytosis), parasites (eg, pinworms), psoriasis, and neoplastic disorders (eg, Paget's disease, Bowen's disease). Psychologic factors may also contribute.

Some topical drugs used to treat anal disorders (eg, lidocaine, benzocaine) may produce an intensely pruritic contact dermatitis. Some oral antibiotics suppress normal bowel flora, causing an overgrowth of intestinal Candida organisms, which leads to pruritus due to perianal candidiasis.

Symptoms and Signs

The hallmark symptom is itching. On physical examination, the perianal area may appear normal, but excoriations from involuntary scratching (during sleep) can often be seen. In advanced cases, secondary bacterial infection may be present, producing edema, erythema, ulceration, and an exudate.

Diagnosis and Treatment

Biopsy of persistent scaly or crusted plaques should be performed to rule out malignancy.

The cause should be determined and corrected. For example, fungal diseases should be treated with over-the-counter topical antifungal powders. Antifungal creams can be used, but they promote excess moisture, which can cause itching. Oral antibiotics should be discontinued, if possible. Patients should not wear synthetic underwear or use perfumes or deodorizers on the perineum. They should be instructed to clean the perianal area gently with moist cotton or hypoallergenic scentless baby wipes after defecation. For mild cases caused by simple irritation, such cleansing followed by application of petroleum jelly can be effective.

The most effective local therapy is 0.5% or 1% hydrocortisone cream. Usually, it is applied only at night, when itching occurs. Severe cases may require application several times a day. The cream is discontinued as soon as itching is controlled. Recurrence is common, but repeated treatment is successful.

Excision of skin tags occasionally helps, but hemorrhoidectomy does not.