Vulvar Cellulitis

Vulvar cellulitis is a spreading bacterial infection of the dermis and subcutaneous tissue of the vulva, usually caused by group A Streptococcus or Staphylococcus aureus.

• It enters through skin breaks from shaving, scratching, surgery, episiotomy, tinea or lymphoedema.
• Diabetes, HIV, obesity, lymphoedema and immunosuppression predispose.
• Early antibiotics prevent spread and complications.

Diffuse red, hot, swollen, tender vulval skin with ill-defined edges.

• Fever, chills, malaise, enlarged tender inguinal nodes, pain on walking and passing urine.
• Differential diagnosis: vulval abscess, Bartholin abscess, contact dermatitis, herpes genitalis, vulval oedema from heart or kidney failure, erysipelas, necrotising fasciitis.
• Complications: abscess, necrotising fasciitis, septicaemia, lymphangitis, recurrence with lymphoedema.

Diagnosis is clinical, with blood tests to gauge severity and exclude a collection.

• Clinical diagnosis; mark the erythema margin with a skin pen and note the time.
• Full blood count, random blood glucose, urea and creatinine, C-reactive protein.
• Blood cultures when febrile above 38.5 degrees Celsius or unwell.
• Swab any wound or discharge for culture.
• Ultrasound to exclude an underlying collection.
• HIV test.

Give early antibiotics against streptococci and staphylococci, and drain any abscess.

• Supportive: elevate and rest, cool compresses, oral fluids, cotton underwear, keep the skin clean and dry, treat tinea and skin cracks.
• Pharmacological: mild disease: flucloxacillin 500 mg to 1 g oral 6-hourly for 7 days (child 12.5 to 25 mg/kg 6-hourly, maximum 500 mg per dose). Moderate or severe disease or fever: flucloxacillin 1 to 2 g IV 6-hourly (child 25 mg/kg 6-hourly, maximum 1 g per dose) until improving for 24 to 48 hours, then oral to complete 7 to 10 days. Penicillin allergy: clindamycin 450 mg oral 8-hourly or 600 mg IV 8-hourly (child 10 mg/kg 8-hourly, maximum 600 mg per dose). Suspected MRSA: add co-trimoxazole 960 mg oral 12-hourly. Analgesia with paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours).
• Procedures: drain any associated abscess under 1 percent lignocaine (maximum 3 mg/kg, absolute maximum 200 mg plain); urgent surgical debridement for necrotising infection.
• Special groups: in pregnancy avoid doxycycline and avoid co-trimoxazole in the first trimester; in diabetes keep glucose at 6 to 10 mmol/L with insulin; in renal impairment (creatinine clearance below 30 mL/min) adjust doses of co-trimoxazole and avoid ibuprofen.
• Red flags: pain out of proportion, crepitus, bullae, skin necrosis, hypotension, rapid spread: give ceftriaxone 2 g IV daily plus metronidazole 500 mg IV 8-hourly plus clindamycin 600 mg IV 8-hourly and arrange urgent surgical debridement.
• Follow-up: review at 48 to 72 hours for the erythema margin; review at 1 and 4 weeks; treat risk factors to prevent recurrence.