Vulvovaginal itching

Vulvovaginal itching is pruritus of the vulva, vagina or both, and is chronic when it lasts over 6 weeks. Acute itching with discharge is usually infective. Chronic itching without discharge is usually a dermatosis (lichen sclerosus, lichen simplex chronicus, contact dermatitis), and itching that persists or fails treatment needs biopsy to exclude vulval intraepithelial neoplasia and carcinoma.

Anatomy. The labia majora are keratinised and hair bearing. The labia minora and vestibule are non keratinised. The vagina has little sensation, so true vaginal itch is uncommon and usually arises from the vulva or vestibule.

Innervation. Pudendal nerve (S2 to S4), ilioinguinal and genitofemoral nerves.

Mechanisms. Scratching causes inflammation, thickening and fissuring, which worsen itch (itch scratch cycle). Itch arises through histaminergic, non histaminergic and neuropathic mechanisms. Antihistamines help histaminergic itch only.

Classification. By duration: acute (under 6 weeks) or chronic. By discharge: with or without. By skin findings: visible skin change (dermatosis, infection, neoplasia) or normal appearance (neuropathic, early dermatosis, psychogenic, systemic).

Temporal patterns. Premenstrual flares suggest candidiasis. Nocturnal itching suggests scabies, threadworm or lichen simplex chronicus. New onset after menopause suggests atrophy, lichen sclerosus or neoplasia.

History

• Itch: duration, site, nocturnal pattern, relation to menses, scratching, soreness or burning (overlap with vulvodynia), dyspareunia.
• Associated: discharge, rash, ulcers, urinary or faecal incontinence, perianal itching, bowel symptoms.
• Skin disease: atopy, psoriasis, eczema, extragenital white patches (lichen sclerosus), mouth lesions (lichen planus), scalp or nail disease.
• Exposures: soaps, wipes, pads, pantyliners, condoms, lubricants, spermicides, detergents, topical benzocaine, antifungals, neomycin, shaving or depilation, douching, excessive washing.
• Household or sexual contacts with itch (scabies, lice).
• Systemic: fatigue, pallor, weight loss, night sweats, jaundice, thirst, polyuria, menopausal status, pregnancy.
• Drugs: opioids, chloroquine, SGLT2 inhibitors, recent antibiotics or steroids.
• Mood, anxiety and previous treatments.

Examination

• Skin at other sites: scalp, nails, flexures, mouth, hands (burrows).
• Vulva under good light with magnification: erythema, scaling, lichenification (thick skin with exaggerated markings), excoriation, fissures.
• Lichen sclerosus: white atrophic wrinkled skin in a figure of eight around vulva and anus, loss of labia minora, clitoral hood fusion, purpura, fissures.
• Lichen planus: erosive vestibular lesions, white lace pattern, vaginal synechiae.
• Other signs: satellite pustules (candidiasis), well demarcated red plaques (psoriasis), nits or lice (pubic lice), annular edge (tinea), hyperkeratotic, pigmented or ulcerated lesions (neoplasia).
• Speculum, bimanual, inguinal nodes, perianal examination, abdomen for hepatomegaly, splenomegaly or mass.

Red flags

• Non healing ulcer, firm or fixed lump, bleeding, pigmented or raised persistent lesion, or white hyperkeratotic plaque.
• Inguinal lymphadenopathy.
• No response to 4 to 6 weeks of appropriate treatment.
• Weight loss, night sweats or generalised lymphadenopathy.
• Jaundice or pale stools.
• Itching of palms and soles in pregnancy.
• Itching with bleeding or suspected abuse in a child.

Organised by mechanism.

Infective and infestations

• Vulvovaginal candidiasis, the commonest infective cause, with discharge.
• Bacterial vaginosis and trichomoniasis (itch usually minor).
• Genital herpes (tingling and itch before vesicles).
• Anogenital warts and molluscum contagiosum.
• Tinea cruris (annular edge, groin involvement).
• Erythrasma (coral pink fluorescence under Wood lamp).
• Scabies (nocturnal, burrows, household contacts).
• Pubic lice (pediculosis pubis, nits on hairs).
• Threadworm infestation (nocturnal perianal and vulval itch, common in girls).
• Folliculitis and hidradenitis suppurativa.

Dermatoses

• Lichen sclerosus: white atrophic skin, fissures, scarring, long term cancer risk.
• Lichen planus: erosive, vestibular, painful, mucosal involvement at other sites.
• Lichen simplex chronicus: lichenified plaques, nocturnal scratching.
• Irritant contact dermatitis and allergic contact dermatitis.
• Atopic dermatitis, seborrhoeic dermatitis and psoriasis (flexural, often without scale).
• Plasma cell vulvitis (Zoon): well demarcated red orange glazed patch.
• Pemphigus vulgaris and mucous membrane pemphigoid (uncommon).

Hormonal. Genitourinary syndrome of menopause and lactational atrophy.

Neoplastic (serious)

• Vulval intraepithelial neoplasia (usual type, differentiated type).
• Vulval squamous cell carcinoma, often arising in lichen sclerosus.
• Extramammary Paget disease (red, eczematous, non healing).
• Vulval melanoma.

Neuropathic. Pudendal neuropathy, sacral radiculopathy and post herpetic itch.

Systemic

• Iron deficiency anaemia, diabetes mellitus (with candidiasis), thyroid disease.
• Cholestatic liver disease (primary biliary cholangitis, biliary obstruction), chronic kidney disease.
• Polycythaemia vera, Hodgkin lymphoma, HIV infection.

Other

• Urinary or faecal incontinence dermatitis, fistula.
• Anal fissure and haemorrhoids with perianal spread.
• Psychogenic itch, obsessive scratching, delusional infestation.

Special groups

• Pregnancy: intrahepatic cholestasis of pregnancy (generalised itch worse on palms and soles at night, third trimester, no rash), pemphigoid gestationis (periumbilical urticarial plaques and blisters), polymorphic eruption of pregnancy, candidiasis.
• Children: threadworm, nonspecific vulvovaginitis, lichen sclerosus (haemorrhagic blisters, figure of eight), scabies, atopic dermatitis, sexual abuse.

Stepwise reasoning

1. Decide whether there is discharge: if yes, test with pH, microscopy, culture and sexually transmitted infection tests.
2. If no discharge, inspect for skin change and decide on skin scraping, swab or biopsy.
3. Screen for systemic causes when no local cause is found.
4. Biopsy early rather than treating blindly.

Targeted tests

• Vaginal pH, saline and potassium hydroxide microscopy, Candida culture with species identification.
• Skin scraping with potassium hydroxide for tinea, and dermoscopy for scabies.
• Adhesive tape test at dawn for threadworm eggs, or treat empirically when suspected.
• Wood lamp for erythrasma.
• Herpes simplex virus PCR from any fissure or vesicle.
• Patch testing when allergic contact dermatitis is suspected and irritant causes have been removed.
• Full blood count, ferritin, HbA1c or fasting glucose, urea, creatinine and eGFR, liver function tests, thyroid function tests and HIV test for persistent itch without local cause.
• In pregnancy with generalised itch: liver function tests and fasting serum bile acids; a bile acid level of 19 micromol/L or more supports intrahepatic cholestasis of pregnancy.
• Vulval punch biopsy (4 mm under local anaesthetic) from the most abnormal area or ulcer edge for any ulcer, hyperkeratosis, pigmentation, persistent white or red plaque, diagnostic doubt, or failure of 4 to 6 weeks of treatment. For lichen sclerosus, biopsy any area that is thickened, ulcerated or non healing.

Limitations. Candida carriage is common and a positive swab does not prove it is the cause. Wet mount misses many cases. Biopsy of lichen sclerosus can look non specific, and a clinicopathological correlation is needed.

General measures. Stop all irritants, use soap substitutes and an emollient ointment at least twice daily, and use cotton underwear. Avoid scratching, and use cool compresses. Treat the cause once identified; do not apply repeated antifungals without confirming candidiasis.

Specific treatment

• Candidiasis: fluconazole 150 mg orally as a single dose, or clotrimazole 500 mg vaginal pessary once; clotrimazole 1% cream to the vulva for up to 7 days. If recurrent (4 or more episodes in 12 months) and confirmed by culture, fluconazole 150 mg orally on days 1, 4 and 7, then 150 mg once weekly for 6 months, with liver function tests at baseline and during prolonged use. Avoid fluconazole in pregnancy; use clotrimazole 100 mg pessary nightly for 7 days.
• Lichen sclerosus: clobetasol propionate 0.05% ointment, one fingertip unit (0.5 g) to affected skin nightly for 4 weeks, then on alternate nights for 4 weeks, then twice weekly for 4 weeks. Continue as needed for flares and review at 3 months, then at least annually. Monitor for skin thinning and candidiasis. Biopsy any non healing area; the lifetime risk of squamous cell carcinoma is up to about 5%. Refer if there is no response.
• Lichen simplex chronicus: betamethasone valerate 0.1% ointment thinly once or twice daily for 2 to 4 weeks, then reduce. At night add chlorphenamine 4 mg orally (maximum 24 mg daily; avoid in glaucoma, urinary retention and older adults), or amitriptyline 10 mg orally at night increased by 10 mg weekly to a maximum of 50 mg.
• Irritant or allergic contact dermatitis: remove the cause, hydrocortisone 1% ointment twice daily for up to 7 days; escalate to a more potent steroid under review.
• Atrophy: oestradiol 10 microgram vaginal tablet nightly for 2 weeks, then twice weekly; maximum one tablet daily; review at 3 months; report any bleeding.
• Scabies: permethrin 5% cream applied from neck to soles including genitalia, left on for 8 to 12 hours, repeated after 7 days; treat all household and sexual contacts at the same time. Alternative: ivermectin 200 microgram/kg orally as a single dose with food, repeated after 7 to 14 days (avoid in pregnancy and under 15 kg). Post scabetic itch can persist up to 4 weeks.
• Pubic lice: permethrin 1% lotion applied for 10 minutes then rinsed, or malathion 0.5% aqueous lotion applied for 12 hours; repeat after 7 days; screen for other sexually transmitted infection and treat contacts.
• Threadworm: mebendazole 100 mg orally as a single dose, repeated after 2 weeks (avoid under 6 months of age and in the first trimester); treat the household.
• Tinea cruris: terbinafine 1% cream once daily for 7 days, or clotrimazole 1% cream twice daily for 2 to 4 weeks.
• Erythrasma: miconazole 2% cream twice daily for 2 weeks.
• Herpes simplex first episode: aciclovir 400 mg orally three times daily for 5 days, extended to a maximum of 10 days if new lesions appear.
• Neuropathic itch: gabapentin 300 mg orally at night, increased by 300 mg every 3 to 7 days to 900 to 1800 mg daily in 3 doses, maximum 3.6 g daily; reduce for creatinine clearance under 60 mL/min.
• Systemic causes: iron replacement, glycaemic control, thyroid correction, cholestasis management, and urgent haematology review for lymphoma or polycythaemia.
• Intrahepatic cholestasis of pregnancy: same day obstetric review, bile acid monitoring and timing of delivery by bile acid level; ursodeoxycholic acid is specialist initiated and evidence for itch relief is limited.

Monitoring. Review at 4 to 6 weeks. Biopsy if there is no response. Long term yearly review for lichen sclerosus and vulval intraepithelial neoplasia. Check for steroid atrophy during prolonged use.

Referral and escalation. Refer urgently within 2 weeks for suspected carcinoma or ulcer. Refer to a vulval clinic or dermatology for refractory itch, lichen planus, pemphigoid, suspected intraepithelial neoplasia or diagnostic doubt. Refer to obstetrics the same day for itching in pregnancy with abnormal liver tests. Involve child protection services for suspected abuse.

Admission criteria. Rarely needed; severe secondary infection, cholestasis of pregnancy with high bile acids, or lymphoma work up.

Discharge and follow up. Provide a written steroid regimen, explain the long term risk with lichen sclerosus, and arrange review.

Safety netting. Return for ulceration, bleeding, a new lump, persistent itch beyond 6 weeks, or jaundice.