Periurethral itching

Periurethral itching is itch at the urethral meatus and the surrounding skin and mucosa. It is not automatically a urinary tract infection. Cystitis causes dysuria, frequency, urgency and suprapubic pain. Isolated external itch usually has a genital skin, mucosal or sexually transmitted cause.

Anatomy. In men the meatus sits at the glans tip under the foreskin, where moisture, smegma and friction favour balanitis and dermatoses. In women the meatus lies in the vestibule between the clitoris and vagina, close to the Skene gland openings, and depends on oestrogen for mucosal health.

Epidemiology. Vulvovaginal candidiasis is the commonest infective cause in women, and up to three quarters of women have at least one episode. In men, balanoposthitis, contact dermatitis and urethritis dominate. Diabetes and SGLT2 inhibitors raise the risk of candidal infection in both sexes.

Classification.

• By sex and anatomy: urethral, vulvovaginal, penile or surrounding skin.
• Infective versus noninfective (dermatosis, irritant, atrophic, neoplastic, systemic).
• With or without discharge, dysuria or lesions.
• Acute versus chronic (over 6 weeks) or recurrent.

Mechanisms. Mucosal and skin inflammation, yeast overgrowth, atrophic epithelium, and chronic scratching which produces lichenification and perpetuates itch.

History.

• Duration, constant or cyclical (premenstrual worsening suggests candidiasis), nocturnal itch.
• Discharge colour and odour, dysuria, frequency, haematuria.
• Lesions, ulcers, warts, burning.
• Sexual history: new partners, condom use, oral or anal exposure, partner symptoms.
• Irritants: soaps, wipes, douches, perfumed products, detergents, latex, spermicide, pantyliners, tight synthetic clothing, shaving.
• Recent antibiotics, steroids, SGLT2 inhibitors.
• Diabetes symptoms, menopause, pregnancy, atopy, psoriasis, previous lichen.
• Immunosuppression, contact with scabies or lice, threadworm in children.
• Arthritis and conjunctivitis (reactive arthritis).

Examination.

• External genitalia: erythema, fissures, white plaques, lichenification, atrophy, pallor, loss of architecture (labial resorption, clitoral hood fusion), ulcers, warts, nits, burrows.
• Meatus: red fleshy caruncle at the posterior lip, circumferential prolapse, discharge on stripping the urethra, meatal stenosis in men.
• Foreskin: retractability, balanitis, phimosis. Inguinal nodes.
• In women: speculum for discharge, cervicitis and atrophy; bimanual if pelvic pain.
• Urine dipstick, random glucose, pregnancy test in women of reproductive age.

Red flags.

• A focal lesion persisting over 4 weeks, ulceration, induration, bleeding or pigmentation (intraepithelial neoplasia or squamous cancer).
• Genital ulcers or inguinal lymphadenopathy (syphilis, herpes, chancroid, lymphogranuloma venereum).
• Purulent urethral discharge, pelvic pain or fever (pelvic inflammatory disease).
• Suspected sexually transmitted infection in pregnancy.
• Genital symptoms in a child (safeguarding concern).
• New diabetes with recurrent candidal infection.

Men.

• Infective: candidal balanitis, bacterial and anaerobic balanoposthitis, urethritis (Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, Trichomonas vaginalis, Ureaplasma, adenovirus, herpes simplex), genital herpes, meatal warts, scabies, pubic lice, tinea cruris, primary syphilis.
• Noninfective: irritant or allergic contact dermatitis (latex, spermicide, soap), lichen sclerosus (balanitis xerotica obliterans), lichen planus, inverse psoriasis, seborrhoeic dermatitis, plasma cell (Zoon) balanitis, fixed drug eruption, circinate balanitis of reactive arthritis, meatal stenosis, urethral stricture, polyp or foreign body.
• Neoplastic and systemic: penile intraepithelial neoplasia (erythroplasia of Queyrat, Bowen disease), penile carcinoma, diabetes with glycosuria, SGLT2 inhibitor effect.

Women.

• Infective: vulvovaginal candidiasis, bacterial vaginosis, trichomoniasis, urethritis and cervicitis (gonococcal, chlamydial, Mycoplasma genitalium), genital herpes, warts, scabies, pubic lice, threadworm (children).
• Atrophic and anatomical: genitourinary syndrome of menopause, urethral caruncle, urethral prolapse (children and postmenopausal women), Skene gland cyst or abscess, urethral diverticulum.
• Dermatoses: irritant or allergic contact dermatitis, lichen sclerosus, erosive lichen planus, lichen simplex chronicus, psoriasis, eczema.
• Neoplastic and systemic: vulval intraepithelial neoplasia, vulval carcinoma, extramammary Paget disease, diabetes, pregnancy.
• Functional: vulvodynia (burning more than itch).

1. Identify the anatomy, examine, and test the urine. A positive dipstick with external itch only is often contamination. Diagnose urinary tract infection only with urinary symptoms and a positive test.
2. Women: vaginal pH (normal 3.8 to 4.5; over 4.5 in bacterial vaginosis, trichomoniasis and atrophy), saline and KOH microscopy (clue cells, motile trichomonads, yeast and hyphae, whiff test), Amsel criteria (3 of 4: thin homogeneous discharge, pH over 4.5, positive whiff test, clue cells), high vaginal swab culture for Candida in recurrent or atypical disease, and nucleic acid amplification tests for gonorrhoea, chlamydia, trichomonas and Mycoplasma genitalium (vulvovaginal swab or first void urine).
3. Men: first void urine nucleic acid amplification tests for the same organisms. A urethral smear with 5 or more polymorphonuclear leucocytes in each oil immersion field indicates urethritis. Swab for Candida and bacteria; herpes polymerase chain reaction from a lesion; syphilis serology or lesion polymerase chain reaction.
4. Offer HIV, syphilis and hepatitis B serology with consent when sexually transmitted infection is possible.
5. Random glucose or HbA1c (48 mmol/mol or 6.5% or more is diagnostic) for recurrent candidiasis or balanitis.
6. Skin scraping for scabies, patch testing for suspected allergic contact dermatitis.
7. Punch biopsy (3 to 4 mm) for lesions that are persistent, pigmented, ulcerated, indurated or unresponsive to treatment, and for suspected lichen sclerosus with atypia.
8. Persistent symptoms with negative tests: urethroscopy and imaging for stricture, diverticulum or caruncle, and review for dermatosis and neoplasia.

Limits. Wet mount detects only about half of trichomoniasis. Candida colonises 10% to 20% of asymptomatic women and a positive culture alone is not treated.

General measures. Stop irritants. Wash with water or a soap substitute only. Wear cotton underwear. Avoid topical anaesthetics and antihistamines (sensitisers). Use an emollient barrier. No sexual intercourse until treatment and partner treatment are complete (7 days).

Candidiasis.

• Women: clotrimazole 500 mg vaginal pessary once, or fluconazole 150 mg orally once. Add clotrimazole 1% cream to the vulva twice daily for up to 7 days.
• Pregnancy: clotrimazole 100 mg pessary nightly for 7 days. Fluconazole is contraindicated; it interacts with warfarin and QT prolonging drugs.
• Severe: fluconazole 150 mg orally, repeated after 72 hours.
• Recurrent (4 or more episodes in 12 months): fluconazole 150 mg orally every 72 hours for three doses, then once weekly for 6 months.
• Men: clotrimazole 1% or miconazole 2% cream to the glans and foreskin twice daily for 7 days, with hydrocortisone 1% cream for no more than 7 days if inflamed. Correct diabetes.

Bacterial vaginosis. Metronidazole 400 mg orally twice daily for 5 to 7 days (500 mg twice daily for 7 days is also used), or metronidazole 0.75% gel 5 g intravaginally once daily for 5 days. Avoid alcohol during treatment and for 48 hours after.

Trichomoniasis. Women: metronidazole 500 mg orally twice daily for 7 days. Men: metronidazole 2 g orally once. Treat partners. Retest at 3 months.

Urethritis and cervicitis.

• Gonorrhoea: ceftriaxone 1 g intramuscularly once (500 mg in some regimens; adjust to local susceptibility).
• Chlamydia: doxycycline 100 mg orally twice daily for 7 days. In pregnancy use azithromycin 1 g orally once.
• Syndromic urethritis without test results: ceftriaxone 1 g intramuscularly once plus doxycycline 100 mg orally twice daily for 7 days.
• Mycoplasma genitalium: specialist treatment directed by resistance testing, for example doxycycline 100 mg twice daily for 7 days followed by azithromycin 1 g then 500 mg daily for 2 days, or moxifloxacin 400 mg daily for 7 to 10 days.
• Notify and treat partners. Test of cure in pregnancy and when symptoms persist.

Genital herpes (first episode). Aciclovir 400 mg orally three times daily for 7 to 10 days; adjust the dose in renal impairment.

Infestations. Scabies: permethrin 5% cream to the whole body from the neck down (including genitals) for 8 to 12 hours, repeated after 7 days; or ivermectin 200 micrograms/kg orally once, repeated in 7 to 14 days. Pubic lice: permethrin 1% lotion for 10 minutes, repeated after 7 days. Threadworm: albendazole 400 mg orally once, repeated after 2 weeks, with household treatment.

Dermatoses and atrophy.

• Contact dermatitis: remove the allergen and use hydrocortisone 1% cream once or twice daily for up to 7 days.
• Lichen sclerosus: clobetasol propionate 0.05% ointment once nightly for 4 weeks, on alternate nights for 4 weeks, then twice weekly for 4 weeks, then as needed. Long term specialist follow up because of a small lifetime risk of squamous cancer. Men with phimosis or stenosis need urology review for circumcision.
• Genitourinary syndrome of menopause: oestradiol 10 micrograms vaginal tablet daily for 2 weeks then twice weekly, or oestriol 0.5 mg cream; specialist advice with a history of breast cancer. Caruncle and prolapse in adults respond to topical oestrogen.

Monitoring. Review at 2 to 4 weeks. Reassess if there is no response or a lesion persists.

Referral and escalation. Urgent gynaecology, urology, dermatology or genitourinary medicine for suspected neoplasia, persistent or ulcerated lesions, lichen sclerosus, recurrent infection, urethral prolapse needing excision, or suspected sexual abuse in a child.

Admission. Rarely needed; pelvic inflammatory disease with systemic illness is the main exception.

Special groups. Pregnancy: avoid fluconazole and doxycycline, and treat sexually transmitted infection early. Children: examine externally, avoid speculum, consider threadworm, prolapse and safeguarding. Postmenopausal women: atrophy is likely. Diabetes and HIV: expect recurrent candidiasis.