Introduction: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease associated with various comorbidities and diminished quality of life (QoL). Among dermatological conditions, HS is reported to most severely diminish QoL. This study aimed to analyse the health-related QoL (HRQoL) of patients with HS in more detail by using generic to disease-specific HRQoL questionnaires. Correlations between the HRQoL measures and HS disease severity measures were assessed. Methods: We analysed the HRQoL and clinical severity of patients with HS (N = 92) treated in 5 Finnish hospitals using HRQoL measurement tools most often used in dermatological clinics, as well as the generic 15D instrument (standardized and self-administered 15-dimensional measure of HRQoL). The disease severity was assessed using the Hurley stage, International Hidradenitis Suppurativa Severity Score System, and disease severity evaluation by the investigator. Results: The mean 15D score of HS patients was low and comparable with that of patients with cancers. No correlation was found between HS severity measures and 15D score, indicating that even mild HS has a high impact on HRQoL. Conclusions: Our findings strengthen the understanding about HS as a debilitating disease and even compared with non-dermatological conditions and highlight the need of comprehensive care of patients with HS.