Um início duvidoso, um fim incógnito – um caso de tinha incógnita

Tinea incognito is caused by the modification of ringworm after treatment with immunosuppressants, normally topical steroids, which mask its typical characteristics, and result in the progression of the original fungal infection. This is a case of a 71-year-old man who developed a clinical picture involving "bites" [ sic ], pain, and discomfort in the right forearm, associated with papular vesicular lesions that were pinkish in color and non-pruritic. The patient was evaluated and medicated with antivirals, antibiotics, and nonsteroidal anti-inflammatory drugs with no success. He developed violaceous papular-pustular lesions with scaling in about 1 month. After a therapeutic trial with an antifungal agent and the discovery of the patient’s chronic use of topical corticosteroids, a diagnosis of tinea incognito was established. This diagnosis presents a challenge to the general practitioner due to its similarity to various dermatological conditions.