Allergic Vulvitis

Allergic vulvitis is inflammation of the vulva from a type IV (delayed) hypersensitivity reaction to an allergen, or a type I reaction in some cases such as latex.

• Common allergens are fragrances, preservatives, topical anaesthetics, neomycin, spermicides, latex condoms, rubber, nail products transferred by hand, and topical antifungals.
• It requires prior sensitisation, so symptoms appear 24 to 72 hours after exposure.
• Identifying and removing the allergen is the basis of cure.

Intense vulval itching, burning, redness, swelling and weeping after exposure.

• Vesicles, oedema, erythema, exudate and later scaling or lichenification.
• Symptoms recur on re-exposure and may spread to the groin and thighs.
• Differential diagnosis: irritant vulvitis, vulvovaginal candidiasis, herpes genitalis, lichen simplex chronicus, psoriasis, lichen sclerosus.
• Complications: secondary infection, chronic lichenification, anaphylaxis in latex or spermicide allergy.

Diagnosis is by history and exclusion of other causes.

• Detailed history of new products, medicines, condoms, pads, creams and partner products.
• High vaginal swab and potassium hydroxide preparation to exclude candidiasis.
• Patch testing in specialist units when the cause stays unclear or when vulvitis persists.
• Biopsy for atypical or persistent lesions.

Remove the allergen, settle inflammation with a topical corticosteroid, and treat any infection.

• Supportive: stop the suspected allergen; wash with water only; use plain emollient (petroleum jelly) 2 to 3 times daily; cool compresses; cotton underwear; use non-latex condoms (polyurethane) if latex is the cause.
• Pharmacological: mometasone 0.1 percent ointment thinly once daily for 7 to 14 days. Oral antihistamine: cetirizine 10 mg oral once daily in adults and children from 12 years; children 6 to 11 years 5 mg 12-hourly; children 2 to 5 years 2.5 mg 12-hourly. For severe or widespread reaction give prednisolone 40 mg oral daily for 5 days (child 1 mg/kg daily, maximum 40 mg) without a taper. Treat secondary infection with clotrimazole 1 percent cream twice daily for 2 weeks or flucloxacillin 500 mg oral 6-hourly for 5 to 7 days (child 12.5 to 25 mg/kg 6-hourly, maximum 500 mg per dose).
• Procedures: none.
• Special groups: in pregnancy topical corticosteroid and cetirizine 10 mg daily are acceptable; avoid prednisolone courses longer than 5 days without review. In diabetes monitor glucose during oral prednisolone.
• Red flags: facial swelling, wheeze, stridor, hypotension (anaphylaxis): give adrenaline 0.5 mg IM (0.5 mL of 1 in 1000) for adults and children above 12 years, 0.3 mg for children 6 to 12 years, 0.15 mg for children 6 months to under 6 years, repeated after 5 minutes if needed. Also refer for bleeding or non-healing lesions.
• Follow-up: review at 2 weeks; give written advice on allergens to avoid; refer for patch testing if recurrent.