Anal itching

Disease Description (Causes and Symptoms)

• Definition: Pruritus ani is a symptom involving persistent or intermittent severe itching of the anus and the surrounding skin (including the perineum and external genitalia). It is not a single disease and may be caused by various local and systemic factors.
• Main causes (summary): Irritation from residual stool after defecation, excessive cleansing or soap use, moisture (sweat or secretions), foods (spicy foods, coffee, chocolate, citrus fruits, alcoholic beverages, etc.), contact irritation/allergy to hygiene products (scented toilet paper, powder, etc.), disruption of intestinal flora caused by antibiotics, parasites (pinworms), anal diseases (hemorrhoids, anal fistula, anal fissure, rectal polyps, rectal cancer), skin diseases (eczema, psoriasis, fungal infection), and psychological factors (stress and sexual stimulation), among others.
• Pathophysiology: Because the skin around the anus is rich in sensory nerves, even mild irritation may be perceived as itching. The itch–scratch cycle can cause epidermal damage, inflammation, thickening (lichenification), and secondary infection.
• Symptoms: Itching that mainly worsens at night and may be unbearable; redness, infiltration, epidermal peeling, oozing, or fissures caused by scratching; and, when chronic, skin thickening (leathery changes). Pain or sleep disturbance may also occur.

Treatment Methods and Precautions

• Basic principle: Identify possible causes and treat the cause. Most cases improve with conservative management.
• Lifestyle and hygiene management (first-line treatment)
  • Gently wash the anus with lukewarm water and minimize soap use. Do not rub; gently pat dry and completely remove moisture.
  • Use unscented, dye-free toilet paper or unscented wet wipes. Even when using wet toilet paper, dry the area afterward and maintain ventilation.
  • Avoid tight underwear and synthetic fibers; wear breathable cotton underwear. Avoid excessive sitz baths and excessive cleansing.
  • Try avoiding foods that may trigger itching (coffee, black tea, cola, chocolate, citrus fruits, spicy foods, alcoholic beverages, some dairy products, etc.).
  • Improve bowel habits (control constipation and excessive fluid intake, and avoid straining during sitz baths or defecation).
• Medication and topical treatment
  • Barrier agents/moisturizers: Reduce irritation by using skin protectants such as zinc oxide and petroleum jelly.
  • Use a low-potency topical steroid for a short period (e.g., hydrocortisone 1%), on a limited basis (usually 1–2 weeks), to control acute inflammation. Long-term use carries a risk of skin atrophy and other adverse effects.
  • If a fungal infection is suspected, use an antifungal cream; if a bacterial infection is suspected, use an appropriate antibiotic (oral or topical).
  • If pinworms are confirmed, administer an anthelmintic (albendazole or mebendazole) and simultaneous treatment of household contacts is recommended.
  • Steroid-alternative/conservative medication: Topical calcineurin inhibitors (tacrolimus/pimecrolimus) may be used as steroid alternatives in some cases (at the physician’s discretion).
• Treatment of refractory cases (under specialist guidance)
  • Nerve blocks/injections (e.g., alcohol injection to destroy sensory nerves) are selective treatments, and their evidence and complications must be considered.
  • Surgical methods such as skin excision, peeling, or grafting are extremely rare last resorts.
• Precautions (during self-care)
  • Do not rub or scratch forcefully (this may worsen secondary infection and skin damage).
  • Do not repeatedly use strong disinfectants, antibiotics, or topical anesthetics without medical advice (they may cause irritation or allergic reactions).
  • Do not use topical steroids long-term or over wide areas (risk of skin atrophy, pigment abnormalities, etc.).
• Complications: Secondary bacterial or fungal infection, skin erosion or abscess, skin thickening and pigment changes due to chronic itching, sleep disturbance, and worsening of daily life, among others.
• Criteria for specialist referral: Consultation with a colorectal surgeon or dermatologist is recommended if there is no improvement after 4–6 weeks of conservative treatment, or if bleeding, a lump, abnormal discharge, or rectal symptoms occur.

Checklist Before an Outpatient Visit (Including Items to Bring and Example Questions)

• Items/materials to bring
  • A list of currently used medications (including prescription drugs, over-the-counter medicines, and supplements).
  • Notes on when the symptoms began and their course (when they are severe and whether they worsen at night).
  • Records of bowel habits and stool characteristics (frequency, hardness, diarrhea, bloody stool, etc.).
  • Recent diet, allergy history, history of skin disease, and information related to sexual activity (if necessary).
  • Records of previous treatments (ointments, medications, or self-treatment tried) and their effects.
  • If possible, photographs of the anus (to show the medical staff) and recent test results (stool tests, skin tests, etc.).
  • A stool specimen (may be requested if a pinworm test, culture, or similar test is needed).
• Items the doctor may ask about during the visit (organizing these in advance may be helpful)
  • When the itching began and how long it has lasted, and the time of day (whether it worsens at night).
  • How the area is cleaned after defecation (water, soap, toilet paper, wet wipes, etc.) and how often.
  • The names of products currently being used for the anus, such as ointments, suppositories, or powders.

Examples of General Questions to Ask the Doctor

• "What are the possible side effects of this medication (such as a topical steroid), and how long should I use it?"
• "When can I expect the symptoms to improve normally? If they do not improve, what is the next step?"
• "Among lifestyle factors (diet, hygiene, etc.), what should I particularly avoid, and what self-care methods are recommended?"

Examples of Disease-Specific Questions

• "A pinworm (parasitic) infection is suspected. Should I undergo a stool test or an adhesive-tape test (random testing)? Should my family members be treated as well?"
• "If chronic itching persists, is anoscopy or a colonoscopy needed to check for abnormalities inside the rectum (hemorrhoids, anal fistula, or rectal lesions)? When should I be referred to a specialist?"