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Anal Itching: A Merck Manual of Patient Symptoms podcast

Pruritus ani is anal and perianal itching.

The perianal skin tends to itch, which can result from numerous causes (see Table 1: Anorectal Disorders: Causes of Pruritus Ani). Occasionally, the irritation is misinterpreted by the patient as pain, so other causes of perianal pain (eg, abscess) should be ruled out.

Table 1
Causes of Pruritus Ani Category Examples Disorders Bacterial infections Secondary infection caused by scratching Dermatologic disorders Atopic dermatitis Psoriasis Skin tags Fungal infection Candida Local diseases Bowen's disease Cryptitis Draining fistulas Extramammary Paget's disease Parasitic infections Pinworms Scabies Systemic diseases Diabetes Liver disorders Other factors Drugs Antibiotics Hygiene-related problems Excessive sweating Ingested irritants Beer Caffeinated beverages (eg, coffee, cola) Citrus fruits Spices Vitamin C tablets Psychogenic factors Anxiety Topical irritants Local anesthetics Ointments Soaps

Diagnosis is based on the appearance of the anal skin and relevant information from the history. The skin typically shows dullness and thickening, although the underlying pathology is often obscured by excoriation caused by scratching and secondary infection. A scraping of local skin is taken to rule out a fungal infection, and a stool sample should be examined for ova and parasites. Visible lesions should be biopsied.

Foods suspected of causing pruritus ani should be eliminated from the diet. Clothing should be loose, and bed clothing light. After bowel movements, the patient should cleanse the anal area with absorbent cotton or plain soft tissue moistened with water. Liberal, frequent dusting with nonmedicated talcum powder or cornstarch helps combat moisture. HydrocortisoneSome Trade Names
CORTEF
SOLU-CORTEF
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acetate 1% ointment, applied sparingly qid, may relieve symptoms. Systemic causes and parasitic or fungal infections must be treated specifically.

Last full review/revision October 2007 by Parswa Ansari, MD

Content last modified October 2007