Study to Evaluate the Efficacy and Safety of Ruxolitinib Cream in Participants With Hidradenitis Suppurativa (TRuE-HS1)

Inclusion Criteria: * Diagnosis of HS for at least 6 months prior to screening visit. * Mild to moderate HS (Hurley I or II) with the following at both screening and baseline visits: * A total AN count of at least 4, with no draining tunnels AND * Affecting at least 2 distinct anatomical areas * Agreement to NOT use topical and systemic antibiotics for treatment of HS during the vehicle-controlled period. * Agreement to NOT use topical antiseptics, including washes and leave-on products on the areas affected by HS lesions during the vehicle-controlled period and Weeks 16 to 20 of the extension period. * Further inclusion criteria apply. Exclusion Criteria: * Body surface areas to be treated exceed 20% BSA at screening or baseline * Presence of draining tunnels at screening or baseline. * Medical history including current or history of certain infections, cancer, lymphoproliferative disorders and other medical conditions at the discretion of the investigator. * Laboratory values outside of the protocol-defined criteria. * Pregnant or lactating participants, or those considering pregnancy during the period of their study participation. * Further exclusion criteria apply.