Facial tinea incognito: a clinical, dermoscopic and mycological study of 38 cases

Background: Tinea incognito (TI) is a dermatophytic infection of the skin that is modified by steroid use. As a result, it shows atypical clinical presentations that can lead to misdiagnosis. TI occurring on the face is most frequently misdiagnosed as cutaneous fungal infection, however, very limited information is available on facial TI. Objectives: This study aimed to characterize the clinical, dermoscopic and mycological features of facial TI. Materials & Methods: We retrospectively evaluated 38 patients with mycologically proven facial TI at a single institution in Korea between July, 2014 and July, 2021. Results: The patients had a mean age of 59.6 ± 20.4 years and showed a slight female predominance (male-to-female ratio of 1:1.38). The most common clinical presentation was an eczema-like pattern (47.4%), followed by rosacea-like (15.8%), psoriasis-like (10.5%), lupus erythematosus-like (10.5%), cellulitis-like (7.9%), and folliculitis-like (7.9%) patterns. The mean duration from disease onset to diagnostic confirmation was 3.4 months. Overall, 78.9% of the patients had accompanying chronic systemic diseases, and 57.9% had concurrent tinea infections at other skin sites, mainly the feet and toenails. On dermoscopy, scales and dilated vascular patterns (arborizing vessels and telangiectasia) were commonly observed on glabrous skin, with follicular patterns, such as black dots, broken hairs, and empty follicles. The characteristic trichoscopic features were comma, corkscrew, Morse code-like, and translucent hairs. Conclusion: The clinical characteristics and distinct dermoscopic features described in this article may aid in the differential diagnosis of facial TI while reducing diagnostic delays and unnecessary treatments.