Pyoderma gangrenosum (PG) is a rare neutrophilic dermatosis frequently related to chronic inflammatory bowel disease (IBD) often associated with exacerbation of intestinal disease and/or loss of treatment efficacy. However, in patients with comorbidities, such as diabetes, the diagnosis may be a challenge. Here, we report the case of a 68-year-old man with a history of ulcerative rectocolitis (URC), type II diabetes and arterial hypertension, who had been treated with infliximab and adalimumab in the past. In September 2017, patient developed an erythematous, infiltrated and painful lesion of the third distal part of his left leg, with ulcerative evolution, rapidly worsened despite a broad-spectrum antibiotic treatment had been introducted. A worsening of rectocolitis occurred simultaneously. In agreement with the gastroenterologists, patient started a new biological therapy with golimumab, and oral prednisone with slow tapering of steroid dosage following the improvement of both cutaneous and intestinal symptoms. Dermatologists should be aware about the risk of PG in patient suffering from IBDs, and consider this diagnosis in all patients affected by URC developing rapidly extending ulcerative skin lesion. Moreover, therapeutic choice should take into consideration the effectiveness of golimumab on the inflammatory background, which sustains both intestinal and skin disease in this type of patients.