Unmasking Tinea Incognito: Case Study, Insights Into the Pathogenesis, and Recommendations.

Tinea incognito (TI) is a dermatophyte infection that often presents atypically due to the inappropriate use of corticosteroids or other immunosuppressive treatments, complicating its diagnosis and management. This case report describes a 29-year-old American Indian (Maya) female from Yucatán, Mexico, initially diagnosed with inverse psoriasis and treated with topical corticosteroids. Over several months, her condition deteriorated, with lesions spreading and worsening, ultimately revealing TI. The misdiagnosis was attributed to the masking effects of corticosteroids, which suppressed the immune response and facilitated fungal dissemination. The case underscores the diagnostic difficulties of TI, particularly when treatments exacerbate rather than alleviate the condition. Key to diagnosis is the combination of patient history, mycological testing, and clinical examination. The study also highlights the role of chronic glucocorticoid use in impairing antifungal immunity by reducing crucial cytokines like IL-17 and IFN-γ, leading to persistent fungal infections. Furthermore, addressing underlying conditions such as obesity, insulin resistance, and diabetes is essential for effective management. Timely and accurate identification of TI, coupled with appropriate treatment, is critical to prevent complications and improve patient outcomes.