Bacterial Intertrigo

Bacterial intertrigo is inflammation of skin folds caused or complicated by bacterial infection, mostly Staphylococcus aureus, group A streptococci, Pseudomonas aeruginosa and gram negative organisms. Friction, moisture, heat and maceration are the drivers.

Sites: axillae, groin, inframammary, abdominal folds, toe webs, neck folds.

Risk factors: obesity, diabetes, hyperhidrosis, immobility, incontinence, poor hygiene, tight clothing, immunosuppression.

Erythematous, macerated, weeping plaques in the apposed folds with fissuring, odour, tenderness and sometimes pustules, and green discolouration in Pseudomonas infection.

Satellite papules suggest candida overgrowth.

Differential diagnosis: candidal intertrigo, tinea cruris, erythrasma, inverse psoriasis, seborrhoeic dermatitis, contact dermatitis, hidradenitis suppurativa, Hailey Hailey disease, Langerhans cell histiocytosis, extramammary Paget disease, pemphigus vegetans.

Complications: cellulitis, abscess, necrotising infection in diabetes, chronic fissuring, lymphangitis, bacteraemia in immunosuppression.

Clinical, with swab for bacterial and fungal culture in moderate to severe, recurrent or resistant disease.

Wood lamp (coral red in erythrasma, blue green in Pseudomonas).

Glucose, HbA1c, HIV test; full blood count and CRP if systemic features.

Biopsy for persistent unusual lesions.

Keep the folds dry, apply topical antibacterials, and add oral antibiotics for deeper infection.

• Supportive: wash with mild antiseptic or chlorhexidine 2 percent, dry gently, absorbent cotton or linen between folds, loose clothing, weight loss, glycaemic control, manage incontinence, avoid talc.
• Pharmacological: mupirocin 2 percent ointment or fusidic acid 2 percent cream three times daily for 7 days; potassium permanganate 1 in 10,000 soaks for weeping lesions; acetic acid 2 percent soaks or compresses twice daily for Pseudomonas. Oral flucloxacillin 500 mg four times daily for 7 days (children under 12 years 25 mg/kg/day in four divided doses) for moderate disease or cellulitis; clindamycin 300 mg four times daily or erythromycin 500 mg four times daily if penicillin allergic. Pseudomonas: ciprofloxacin 500 mg twice daily for 7 days. Candidal overlay: clotrimazole 1 percent cream twice daily for 2 weeks.
• Procedures: incision and drainage of abscess.
• Special groups: pregnancy, topical mupirocin, oral flucloxacillin or erythromycin base, avoid ciprofloxacin; children, avoid ciprofloxacin and use topical therapy or flucloxacillin; diabetes, aggressive treatment and glucose control; HIV, culture for resistant organisms including MRSA.
• Red flags: fever, rapidly spreading erythema, skin necrosis or crepitus, severe pain, systemic illness, diabetic foot involvement.
• Follow-up: review at 1 week; weight and glycaemic control long term; recurrent disease needs treatment of carriage and evaluation of immunity.