The clinical presentation of autoimmune pemphigus may share some symptoms with various diseases. Differential diagnosis of pemphigus vulgaris includes paraneoplastic pemphigus, erythema multiforme exudative, aphthous stomatitis, acute herpetic stomatitis, squamous lichen planus, bullous pemphigoid, linear IgA bullous dermatosis, dermatitis herpetiformis, Gougerot—Haley—Haley disease, Darier disease, Grover’s disease. We present a clinical case of pemphigus vulgaris mimicking infiltrative and suppurative trichophytosis in a 46-year-old patient. According to the past medical history, for the last six months, the patient had painful rashes on the scalp, for which he applied aniline dyes himself. Due to the lack of efficacy, he visited a dermatovenerologist in a private clinic, diagnosed with infiltrative and suppurative trichophytosis, and treated with oral terbinafine and topical antimycotic agents. Since there was no effect of treatment and the rash spread to the torso and extremities, the patient applied to the Moscow Research Center for Dermatovenerology and Cosmetology, from which he was referred for hospitalization to the affiliate of the Moscow Research Center for Dermatovenerology and Cosmetology «V.G. Korolenko Clinic». On admission, rashes were on the scalp, nasal passages, oral mucous membranes, skin of the chest, abdomen, and back. After examination, a diagnosis of pemphigus vulgaris was made. The patient was treated with methylprednisolone (96 mg/day), azathioprine (100 mg/day), ceftriaxone (2 g/day), topical agents, and supportive therapies, which resulted in significant improvement.