Giant cell lichenoid dermatitis is a recently described pathological entity, which can be seen as an unusual lichenoid drug eruption, a manifestation of sarcoidosis or within herpes zoster scars. Histopathological findings include focal vacuolar alteration of the basal layer with cytoid bodies, dermal and intraepidermal multinucleated giant cells and a mixed chronic inflammatory infiltrate with a lichenoid pattern consisting of lymphocytes, histiocytes, eosinophils and plasma cells. Here, we report a giant cell lichenoid dermatitis in a 41-year-old male patient who developed, 3 days after intravenous treatment with amoxicillin-clavulanic acid for erysipelas of the left leg, a clinical picture suggesting a baboon syndrome characterized by an erythematous and pruritic eruption on the axillary, inguinal and popliteal areas and the anterior side of elbows. This is the first reported case of giant cell lichenoid dermatitis in a patient with baboon syndrome.