Study 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.