We report a 35-year-old female patient with a one year history of a pustular and painful erythematous dermatitis, located in great folds, pubis and abdomen. She was evaluated in primary health care, receiving antifungal treatment, antimicrobials, topical and systemic non-steroidal anti-inflammatory drugs, with no response. A skin biopsy was compatible with subcorneal pustular dermatosis. She was initially treated with prednisone (0.8 mg/kg), observing a partial response. Therefore clotrimoxazole was initiated, obtaining an excellent response after 30 days of treatment.