Rosacea-like tinea incognito due to Trichophyton mentagrophytes vr. mentagrophytes.

Tinea incognito is a dermatophytosis with atypi-cal clinical manifestation in the absence of the typical " ringworm " (1). The term tinea incognito was originally used in 1968 by Ive and Marks in 14 patients with atypical dermatophytic infection caused by a previous steroid treatment (2). Since then, several cases of tinea incognito have been described after topical application of pimecrolimus and tacrolimus, although the use of corticosteroids continues to be the most common trigger of the disease (3). A 47-year-old woman presented at our Institute with a 3-month history of erythematous papules with rare pustules on the face. The patient reported a three-month application of topical corticosteroids and metronidazole cream with progressive exacerba-tion of the eruption. Physical examination revealed numerous papules and some pustules forming an erythematous plaque localized on the face (Fig.1). No pathologic signs were observed on the rest of the body and nails. The pa-tient's history was otherwise unremarkable. Scrapings from the facial lesion, examined directly in 10% potassium hydroxide solution, showed the presence of dermatophyte hyphae. Culture on Mycosel Agar (agar-dextrose + cyclo-eximide + chloramphenicol) at 27 °C for three weeks yielded colonies with a powdery and granular surface and yellowish reverses (Fig. 2). Microscopically, we observed round and pyriform microconidia, spiral hyphae and rare smooth-walled macroconidia. These findings confirmed the diagnosis of dermatophyte infection caused by Trichophyton mentagrophytes vr. mentagrophytes. A diagnosis of rosacea-like tinea incognito was made and the patient started therapy with oral terbi-nafine 250 mg/die for 4 weeks, with progressive and total resolution of the facial lesions. Tinea faciei, a relatively uncommon dermatophyte infection, usually shows up as an erythematous, scaly patch with an annular edge, the size of which gradually increases. Clinical presentation of the condition is often atypical. The absence of classical features of ringworm, likely because of the complex anatomy of the face, makes the initial diagnosis difficult and often leads to misdiagnosis of tinea faciei (1). Figure 1. Papules and some pustules forming an ery-thematous plaque on the face. Figure 2. Macroscopic appearance of Trichophyton mentagrophytes colonies.