What are the recommended diagnostic steps and treatment options for a suspected dermatophyte infection that began in the inguinal region, failed to respond to topical corticosteroid-antifungal combination therapy and oral fluconazole, and has now spread to the umbilicus, hands, and feet (presenting with intensely erythematous, blistering lesions)?
Because the previous treatments didn't work, the next best step is to confirm the diagnosis. I recommend seeing a dermatologist for a gentle skin scraping (KOH test) or a fungal culture to identify the exact culprit. Sometimes, combination steroid creams can actually cause fungal infections to spread and change appearance. Depending on your test results, your doctor may suggest a different oral antifungal, such as terbinafine or itraconazole, to target the infection more effectively.