Abstract Background: Hidradenitis suppurativa (HS) is associated with various somatic and psychiatric comorbidities. Data regarding comorbidities in young patients with HS are sparse. Objective: We analyzed both somatic and psychiatric comorbidities in young patients in a nationwide HS cohort. Methods: In this retrospective case-control study, data from cases of HS in young (age 5 to <18 years) patients and age-matched controls with benign melanocytic nevi were collected from the Finnish Care Register for Health Care. The prevalence of preselected comorbidities was compared between the HS and control groups. Results: A total of 153 HS cases were found in the specified age group. Of these, 34.0% had at least 1 somatic comorbidity compared with 4.9% of the controls. At least 1 of the preselected psychiatric diagnoses was present before the age of 18 years in 15.7% of case patients with HS compared with in 5.6% of the controls. By the age of 23 years, 23.5% of the patients with HS and 8.7% of the controls had at least 1 identified psychiatric comorbidity. Limitations: Despite this being one of the largest HS cohorts ever studied, the number of young patients with HS was relatively low. Because this was a registry-based study, it was not possible to verify the accuracy of the International Classification of Diseases codes. Conclusions: Physicians should monitor young patients with HS for both somatic and psychiatric comorbidities.