Hidradenitis suppurativa (HS) is a debilitating, chronic, painful inflammatory disease. Scientists have previously suggested that there is a potential genetic link predisposing Down syndrome patients to the development of HS through the increased formation of the amyloid precursor protein. However, this laboratory based finding had not previously been verified in the population. In this study, we evaluated the commonness of hidradenitis suppurativa within a large group of patients who had Down syndrome, and we used another groups of patients that did not have Down syndrome to compare findings. We observed that the diagnosis of hidradenitis suppurativa was present among 2.1% of patients with Down syndrome over the past five years. Compared to those without Down syndrome, patients with the condition had five times the likelihood of having hidradenitis suppurativa during the period of the study. Hidradenitis suppurativa was most common among Down syndrome patients who were aged 18–29 years. Hidradenitis suppurativa affected males and females, and whites and non-whites, with Down syndrome equally. The diagnosis of hidradenitis suppurativa is made at a younger age among patients with Down syndrome, compared to patients without the condition. This suggests that hidradenitis may occur earlier in life among patients with Down syndrome, or it may occur more severely and thereby prompt earlier visits to the doctor for this condition. It is also possible that hidradenitis suppurativa is diagnosed earlier among patients with Down syndrome because doctors may be examining patients with Down syndrome more frequently in general.