The purpose of this observational, prospective, non-interventional, multicenter, open-label, single arm study in Hidradenitis suppurativa (HS) is to assess the treatment pattern of secukinumab in a flexible dosing regimen and decision influencing factors for flexible dosing in a real-world population over 2 years.

The study will collect data from patients during routine secukinumab treatment and will be representative of the real-world patient population eligible for secukinumab treatment in Germany.

In order to attain widespread representation of health care practices related to the use of secukinumab in the approved indication of moderate to severe HS, a broad spectrum of dermatology practices and clinics who are treating patients with HS across Germany will be included.

Inclusion Criteria:

Patients eligible for inclusion in this study have to fulfill all of the following criteria at enrollment:

1. Patients who provide written informed consent to participate in the study
2. Male and female patients with ≥18 years of age
3. Diagnosis of clinically unequivocal moderate to severe HS
4. Patients for whom a therapy with secukinumab is medically indicated
5. Documented decision for treatment with marketed secukinumab regardless of this noninterventional study
6. Treatment with secukinumab according to the latest version of SmPC
7. Initial treatment with marketed secukinumab planned for up to 1 week before the baseline visit

Exclusion Criteria:

Patients fulfilling any of the following criteria at enrollment are not eligible for inclusion in this study. No additional exclusions may be applied by the investigator, in order to ensure that the study population will be representative of all eligible patients:

1. Patients who have any contraindications, such as a history of or active inflammatory bowel disease (Crohn´s disease, ulcerative colitis), and are not eligible for treatment with secukinumab according to the SmPC
2. Any medical or psychological condition in the treating physician's opinion which may prevent the patient from the study participation
3. Simultaneous participation in any investigational trial or simultaneous participation in another Novartis-sponsored non-interventional study with secukinumab
4. Previous exposure to IL-17 inhibitors
5. For biologic-naïve patients, previous exposure to another biologic drug, such as anti-TNF-α inhibitors

patients, being treated for HS with secukinumab according to the summary of product characteristics (SmPC), after the approval of secukinumab has been granted in this indication.