Background Erythrasma is a skin infection which is caused by Corynebacterium minutissimum. Interdigital erythrasma is the most common form.
Objective The aim of this study was to detect the frequency and risk factors of interdigital erythrasma in patients with clinically suspected tinea pedis.
Methods This study was conducted between June and December 2010 and included 122 patients who had interdigital foot lesions. All patients were examined using a Wood’s lamp. The smears were stained using Gram’s method. Direct examination was performed using 20% potassium hydroxide. Sabouraud dextrose agar and brain heart infusion agar were used for cultures. Moreover, the demographical characteristics of patients, concomitant diseases and clinical findings were also recorded. Cases that were found to be positive on Wood’s lamp examination and/or Gram staining/culture were considered as erythrasma.
Results The rate of erythrasma was found to be 46.7%. The mean age was 43.6 years, and the disease was more prevalent in men. The most common clinical finding was desquamation. Mycological examination was found as positive in 40.35% of the patients. No growth was observed in bacteriological cultures. It was found that using only Wood’s lamp examination or Gram staining resulted in 11 (9%) and 19 positive patients (15.6%), respectively, whereas using both Wood’s lamp examination and Gram staining concurrently resulted in 27 positive patients (22.1%).
Conclusion Interdigital erythrasma is a commonly seen condition and can clinically mimic tinea pedis. A Wood’s lamp is a good diagnostic tool, but Gram staining, particularly in those with a negative Wood’s lamp result, may be a useful method.