High Prevalence of Erythrasma in Patients with Inverse Psoriasis: A Cross-sectional Study.

BACKGROUND: Inverse psoriasis is characterized by erythematous nonscaly plaques in intertriginous regions. Similarly, erythrasma, a superficial infection caused by Corynebacterium minutissimum (C. minutissimum), is also found in skin folds with red-brown lesions, making the distinction between psoriasis and erythrasma difficult. No studies have previously determined whether these two clinically similar cutaneous disorders can occur concurrently. METHODS: Thirty patients with inverse psoriatic plaques were examined using a standard Wood's lamp to visualize porphyrins associated with C. minutissimum. RESULTS: Just over half (56.6%) of patients with inverse psoriatic plaques showed evidence of this bacterium. Specifically, 45.5 percent of inverse psoriatic lesions were found to be positive for C. minutissimum, with the highest prevalence of erythrasma located in the gluteal cleft. CONCLUSION: Clinical suspicion for C. minutissimum should be high in patients with inverse psoriasis due to the organism's potential to trigger or exacerbate psoriatic lesions. Further studies are indicated to determine the response to treatment in patients with this combination.