Tinea Incognito Caused by Microsporum spp. Mimicking Subacute Cutaneous Lupus Erythematosus—Case Report

Tinea incognito is an incorrectly diagnosed form of fungal infection due to a changed clinical picture as a result of systemic or topical corticosteroids or even local immunomodulators. This type of skin lesion is most often located on the trunk but can affect any part of the body. We present a case report of 76-year-old woman with a history of systemic lupus erythematosus who was admitted to hospital because of extensive, painful, and burning erythematous and papular lesions in an annular pattern, covered with a thick, yellow crust, located on the scalp and neck. The skin lesions were accompanied by extensive hair loss. The patient had previously undergone intensified treatment of the underlying disease due to the exacerbation of skin lesions of a subacute cutaneous lupus erythematosus type. A suspicion of tinea incognito was raised, and direct mycological examination and culture confirmed the presence of dermatophytes (Microsporum spp.). Tinea incognito can be difficult to diagnose because the clinical picture is relatively nonspecific and can mimic other dermatoses, such as subacute lupus erythematosus. Therefore, in doubtful cases it is necessary to perform a direct test and culture for fungal infection, especially before initiating treatment with glucocorticosteroids and other immunosuppressive agents.