Erythrasma is a skin infection caused by Corynebacterium minutissimum, a part of the normal skin flora. Optimal conditions for bacterial growth are provided by moist skin fold areas. The infection is particularly common in obese individuals with diabetes mellitus. Patients present with well-demarcated erythematous or brown patches with fine scaling and wrinkling in intertriginous areas (e.g., groin, toe webs). The diagnosis is confirmed by coral-red fluorescence under wood lamp examination. Local disease is treated with topical antibiotic therapy, while extensive disease requires systemic antibiotic treatment.
- Pathogen: Corynebacterium minutissimum
- Risk factors
- Location: intertriginous areas (e.g., toe webs, groin, axilla)
- Skin lesion: well-demarcated erythematous or brown patches with fine scaling and wrinkling
- Pruritus is usually absent or mild.
Intertrigo (intertriginous dermatitis) 
- Definition: dermatitis that particularly affects skin folds (submammary, inguinal, interdigital)
- Clinical features
- Diagnosis: Secondary infections can be confirmed with microbiological testing.
- Uncomplicated intertrigo
- If secondary infection is present: Treatment depends on the organism.
- Prognosis: excellent in absence of complicating factors (e.g., immunosuppression/immunodeficiency)
The differential diagnoses listed here are not exhaustive.
- General: improved skin hygiene, maintaining dry skin (e.g., with cotton or linen cloth)
- Medical therapy
- Prognosis: Recurrence is common.