The purpose of this study is to evaluate the maximal use of ruxolitinib cream in adult and adolescent participants with hidradenitis suppurativa.

Inclusion Criteria:

• Diagnosis of HS for at least 6 months before screening visit.
• Diagnosis of HS (Hurley Stage I, II, III) with a total abscess and inflammatory nodule count of at least 4 and affecting at least 3 distinct anatomical areas at screening and Day 1 visits.
• Total estimated treatment BSA > 20% at screening and baseline.
• Agreement to not use topical or systemic antibiotics for treatment of HS during the Maximal Use Treatment Period.
• Willingness to avoid pregnancy or fathering children based on the criteria defined in the protocol.
• Further inclusion criteria apply.

Exclusion Criteria:

• Current or history of skin condition(s) other than HS that might confound the evaluation of HS; clinically uncontrolled cardiovascular disease; thrombosis; certain cancers; certain infections; severe anemia, thrombocytopenia, or neutropenia; other medical conditions at the discretion of the investigator.
• Laboratory values outside of the protocol-defined ranges.
• Further exclusion criteria apply.