Canadian Humira Post Marketing Observational Epidemiological Study : Assessing Humira Real-life Effectiveness and Impact on HS Burden of Illness

* Has a clinical diagnosis of moderate to severe HS according to the treating physician judgment * Need a change in ongoing therapy for any reason, but not limited to inadequate response, intolerance, sub-optimal compliance, or patient preference. Patient will be approached to participate in the study after a decision to change patient's therapy for Humira® is made by the treating physician. * Has provided written informed consent (Patient Authorization) for participation in the study

* Is participating in a clinical interventional study * Was treated with Humira®, or any other biologic agents for HS prior to baseline visit * Has any other active skin disease or condition that, in the opinion of the treating physician, prohibits the patient from participating in the study or obscures the assessment of the treatment of HS