Erythrasma

Erythrasma is a chronic superficial infection of the intertriginous skin caused by Corynebacterium minutissimum, producing well demarcated brown red patches in the groin, axillae, toe webs and under breasts. It is more common in warm climates, obesity, diabetes, older age and hyperhidrosis.

• Seen in people with poor hygiene or shared bathing facilities.
• Often coexists with tinea or candida.

Sharply defined, slightly scaly, red brown or pink patches with fine wrinkling and minimal itch, in axillae, groin, inframammary folds, intergluteal cleft and toe webs (fourth web space).

• Wood lamp shows coral red fluorescence from porphyrins.
• Differential diagnosis: tinea cruris and pedis, candidal intertrigo, inverse psoriasis, seborrhoeic dermatitis, contact dermatitis, acanthosis nigricans, pityriasis versicolor, bacterial intertrigo, Hailey Hailey disease.
• Complications: chronic persistence, secondary eczematisation, hyperpigmentation, recurrence, secondary infection.

Clinical with Wood lamp examination.

• Skin scrapings for KOH to exclude dermatophytes and candida; Gram stain showing gram positive rods.
• Culture is seldom needed.
• Glucose or HbA1c and weight assessment.

Antibiotics against Corynebacterium and control of moisture.

• Supportive: wash with antibacterial soap, dry skin folds, loose cotton clothing, weight loss, avoid sharing towels and wash cloths, control hyperhidrosis, optimise glycaemia.
• Pharmacological: oral erythromycin 500 mg four times daily for 14 days (children 30 to 50 mg/kg/day in divided doses), or clarithromycin 1 g single dose, or doxycycline 100 mg twice daily for 7 days. Topical clindamycin 1 percent lotion twice daily for 2 weeks; fusidic acid 2 percent cream three times daily for 2 weeks; miconazole 2 percent cream twice daily for 2 weeks (covers candida co infection); benzoyl peroxide 5 percent wash for 2 weeks. Use oral therapy for extensive disease.
• Procedures: none.
• Special groups: pregnancy, topical erythromycin or clindamycin or oral erythromycin base; children under 8 years, erythromycin; diabetes, treat for longer and optimise glycaemia; HIV, extended therapy.
• Red flags: spreading cellulitis, fever, ulceration, treatment failure suggesting alternative diagnosis, extensive disease in immunosuppression.
• Follow-up: review at 2 weeks; antiseptic washes weekly for 2 to 4 weeks to prevent recurrence.