Erythrasma Revisited: Diagnosis, Differential Diagnoses, and Comprehensive Review of Treatment

Abstract

Erythrasma is a bacterial infection of the skin typically caused by Corynebacterium minutissimum. This pathogen infects the stratum corneum in warm and wet areas of the skin. Most commonly, the axillary, inguinal, and interdigital regions are affected. A 60-year-old man presented for the examination of a pedunculated lesion on his right proximal thigh. Upon examination of the lesion, adjacent areas of central hypopigmentation and peripheral hyperpigmented scaling were also noted bilaterally in the groin region. Differential diagnoses of candidiasis, dermatophyte infection, erythrasma, pityriasis versicolor, and terra firma-forme dermatosis were considered. Wood lamp examination revealed bright coral-pink fluorescence. Correlation of the clinical examination and the Wood lamp finding established the diagnosis of erythrasma. Twice daily topical 2% mupirocin ointment therapy led to the resolution of our patient's erythrasma. In this case report, the diagnosis, differential diagnoses, and treatment of erythrasma are reviewed.

Keywords: corynebacterium; diagnosis; differential; erythrasma; infection; lamp; minutissimum; mupirocin; treatment; wood.

Figure 1. Clinical presentation of erythrasma on the right inguinal fold

A 60-year-old man presented for a skin check. He was concerned about a pedunculated lesion on his right proximal thigh (circled in red). Clinical examination also showed a central area of hypopigmentation with peripheral hyperpigmentation and scaling (circled in white) on his right inguinal fold (A). Wood lamp examination revealed a bright coral-pink fluorescence characteristic of erythrasma on the right inguinal fold (B). After six weeks of twice daily topical application of 2% mupirocin ointment, the biopsy site had healed (circled in red), and his previous lesion of erythrasma (circled in white) had resolved (C). Wood lamp examination was negative for erythrasma on his right inguinal fold; there was no residual coral-pink fluorescence (circled in white) after six weeks of topical 2% mupirocin ointment therapy (D).

Figure 2. Clinical presentation of erythrasma on the left inguinal fold

Clinical examination also showed a central area of hypopigmentation with peripheral hyperpigmentation and scaling (circled in white) on his left inguinal fold (A). Wood lamp examination revealed a bright coral-pink fluorescence characteristic of erythrasma on the left inguinal fold (B). After six weeks of twice daily topical application of 2% mupirocin ointment, his previous lesion of erythrasma (circled in white) had resolved (C). Wood lamp examination was negative for erythrasma on his left inguinal fold; there was no residual coral-pink fluorescence (circled in white) after six weeks of topical 2% mupirocin ointment therapy (D).