Ben Abdallah H, Bech R, Fogh K, et al. - Researchers conducted this nationwide registry nested case‐control study to examine the mortality, prevalence and risk of comorbidities in patients with pyoderma gangrenosum (PG). The sample consisted of all inpatients and outpatients diagnosed with PG in tertiary dermatology centers between January 1, 1994, and December 31, 2016, in Denmark. They used the Danish National Patient Registry to identify all patients and to obtain data on comorbidity. In total, 1,604 patients with PG were matched with 16,039 controls. Some associations were known, such as inflammatory bowel disease, while others, such as osteoporosis, had not previously been described. Patients with PG have an increased mortality rate, as well as an increased prevalence and risk of both previously reported and novel comorbidities, which can have serious consequences if undiagnosed. The findings mostly pertain to moderate and severe PG.