The DLQI consists of ten questions regarding patients' perception of the impact of their disease on different aspects of their health-related quality of life (symptoms and feelings, impact on daily activities, leisure, work, school, personal relationships, and problems with treatment) over the last seven days. The highest possible total score for the DLQI is 30 and higher scores indicate a more severe impact on quality of life.

The impact of Hidradenitis Suppurativa (HS) on daily life will be studied using seven additional questions on the symptoms experienced by the patient and the impact of HS on daily life over the past three months: physical and psychological fatigue, anxiety, sleep quality, discomfort with dressing, discomfort with washing, and sex and love life. Responses will be collected at each visit by a four-point Likert scale. The improvement will be defined by the decrease of at least one point on the Likert scale between the enrolment visit and the follow-up visits.

The proportion of patients having stopped at least one of these substances during follow-up will be calculated, and as well as the proportion of patients having stopped one of these substances without using them again until the end of follow-up.

Absenteeism due to HS will be measured by the number of days off taken and the number of days on sick leave over the last three months (enrolment visit and visit at 3 months) or since the last visit (visits at 6, 12, 18 and 24 months). The number of days and its evolution since enrolment will be presented at each visit.

The family member's quality of life will be measured using the FDLQI. The FDLQI is a 10-item-questionnaire with a total score resulting in a maximum of 30 and a minimum of 0 (the higher the score, the more quality of life is impaired). The questionnaire will be proposed to one of the family members (one per patient, the same person throughout the study) going with the patient to the baseline visit and 3, 6, 12, 18 and 24 months after secukinumab initiation. The assessment will refer to the last seven days.

Secukinumab dose regimen prescribed at baseline to describe the use of secukinumab.

Proportion of patients receiving up-titration (q4w-to-q2w) or down-titration (q2w-to-q4w) and proportion of patients receiving more than one up-and/or down-titration

Time spent under each treatment regimen (q4w and q2w) and reason for change

Total duration of secukinumab treatment (i.e. time elapsed until treatment is discontinued), reason for discontinuation

Proportion of patients with at least one temporary discontinuation and its reason

Proportion of patients taking all prescribed doses to measure the treatment compliance

Proportion of patients achieving at least 55%, 75% and 100% reduction in International Hidradenitis Suppurativa Severity Score System (IHS4) (IHS4-55, 75, 100).

The IHS4 score corresponds to: (number of nodules multiplied by 1) + (number of abscesses multiplied by 2) + [number of drainage tunnels (fistulas/sinuses) multiplied by 4]. A score of 3 or less corresponds to mild HS, a score of 4 to 10 to moderate HS and a score of 11 or more to severe HS

Evolution of AN count (total abscesses and inflammatory nodules)

Percentages of patients with onset or worsening of flares will be described from the data concerning flares collected by the physician at each visit.

Itching due to pruritus will be evaluated using an 11-point NRS scale with 0 being "no itch" and 10 being the worst itch imaginable.

Treatments of interest will include systemic antibiotics, pain medications and psychotropic drugs.

Proportion of patients who had a surgical procedure will be provided

Use of dressings and protections for wound care after secukinumab initiation, evaluated by the use of dressings and protections in the seven days prior to visits (data collected by the patient)

Description of the reasons for secukinumab initiation (e.g.: patient complaints, clinical symptoms, safety events) declared by the participating physician.