Successful Treatment of Cutaneous Protothecosis Due to Prototheca wickerhamii with Terbinafine

Protothecosis, an infrequent human infection, is caused by achlorophyllic algae belonging to the genus Prototheca, particularly Prototheca wickerhamii. The skin stands as the most commonly affected organ. This report documents a case involving an 82-year-old male with Protothecosis. Histopathological analysis revealed granulomatous inflammation in the dermis, exhibiting necrotic features and hosting numerous non-budding spherical organisms. These organisms were positively stained using methenamine silver and periodic acid-Schiff stains, confirming identification as P. wickerhamii after validation through tissue culture and sequencing procedures. Initially, the patient received oral itraconazole at a dosage of 200 mg daily, accompanied by topical 1% naftifine-0.25% ketoconazole cream for a duration of 4 weeks, resulting in significant improvement. Subsequently, due to gastrointestinal discomfort presumably linked to itraconazole, terbinafine was administered. Over a span of 3 months, the patient received oral terbinafine at a dosage of 250 mg/day alongside the application of topical 1% naftifine-0.25% ketoconazole cream, leading to complete healing of the skin lesion, leaving behind a fibrotic scar.