Erythrasma – A Red Herring in the Ongoing Epidemic of Tinea

Abstract

We describe the presentation of five adults with erythrasma, misdiagnosed as tinea and prescribed antifungal treatment which resulted in incomplete clearance. The lesions were restricted to axillary and/or inguinal folds. They were dry, brown macules with fine scaling. Except for one with moderate pruritus, they were asymptomatic. No fungal elements could be demonstrated in any of the patients in 10% KOH preparation. Gram stain revealed short gram-positive rods in varying proportions. All the patients showed a pink fluorescence on Wood’s lamp examination. After treatment with topical clindamycin singly or in combination with oral azithromycin, there was complete clearance of the lesions leaving normal-appearing skin in three and residual hyperpigmentation in one. The overdiagnosis of tinea in the ongoing epidemic of dermatophytosis is a potential concern. Wood’s lamp examination is very useful to confirm or exclude erythrasma.

Erythrasma

“…1 A false negative may CME at jamacmelookup.com result if the area was recently washed, as the porphyrins are water soluble. 2 Skin biopsy specimens can confirm the presence of superficial infection, but are often unnecessary with typical cutaneous morphology and positive Wood lamp examination. 1 Treatment is generally effective and consists of keeping the skin clean and dry with application of topical antibiotic until clear.…”

“…This gram-positive rod is part of the normal skin flora, but under moist conditions, it proliferates in the stratum corneum . It is associated with type 2 diabetes, obesity, hot climates, immunocompromised states, and advanced age . Clinically, erythrasma may present as a pink, red, or brown plaque in intertriginous areas, such as the axilla, inframammary folds and inguinal region .…”

“…It is associated with type 2 diabetes, obesity, hot climates, immunocompromised states, and advanced age . Clinically, erythrasma may present as a pink, red, or brown plaque in intertriginous areas, such as the axilla, inframammary folds and inguinal region . In skin of color, lesions tend to appear darker and more brown with subtle erythema, with the potential for postinflammatory pigmentary changes .…”

“…Clinically, erythrasma may present as a pink, red, or brown plaque in intertriginous areas, such as the axilla, inframammary folds and inguinal region . In skin of color, lesions tend to appear darker and more brown with subtle erythema, with the potential for postinflammatory pigmentary changes . Differential diagnoses include infections, such as tinea or candidiasis, inverse psoriasis, Hailey-Hailey disease, Darier disease, contact dermatitis, and granular parakeratosis .…”

“…In erythrasma, a classic coral-red fluorescence is observed due to coproporphyrin 3 that is produced from the caustic bacteria on exposure to the light . A false negative may result if the area was recently washed, as the porphyrins are water soluble . Skin biopsy specimens can confirm the presence of superficial infection, but are often unnecessary with typical cutaneous morphology and positive Wood lamp examination .…”