Study of Ruxolitinib Cream for the Treatment of Discoid Lupus Erythematosus

Inclusion Criteria: * Ability to understand and comply with the protocol and provide informed consent. * Speaks English. * Age ≥ 18 years. * Clinical diagnosis of discoid lupus as assessed by the PI. * At least one active (inflamed) discoid lesion with an IGA score of ≥ 3 and with a diameter ≥ 1cm at screening and baseline. Two lesions with equal scores will be necessary if consenting to pre-and post-treatment biopsies. * Maximum body surface area of 20%. Exclusion Criteria: * Unwillingness or inability to complete informed consent process or comply with the study protocol. * Pregnant or breast-feeding women, or women planning to become pregnant or breastfeed during the study. * History of coagulopathy, pulmonary embolism or deep venous thrombosis. * History of cutaneous squamous cell carcinoma localized to the treatment area. * Serum creatinine \> 1.5 mg/dL, or alanine aminotransferase or aspartate aminotransferase \> 1.5 × upper limit of normal. * Other dermatologic disease besides discoid lupus whose presence or treatments could complicate assessments. * Other diseases besides dermatologic disorders whose treatment could complicate assessments. Subjects with systemic lupus erythematosus are permitted as long as they do not have unstable disease and meet all other criteria, including the exclusion criteria for systemic immunosuppressive or immunomodulating drugs (below). * Topical treatments for discoid lupus within 2 weeks of Visit 2. * Systemic immunosuppressive or immunomodulating drugs (e.g. oral or injectable corticosteroids, methotrexate, cyclosporine, mycophenolate mofetil, azathioprine) other than antimalarials (hydroxychloroquine, chloroquine, quinacrine) within 4 weeks or 5 half-lives of Visit 2 (whichever is longer). * Potent systemic cytochrome P450 3A4 inhibitors or fluconazole within 2 weeks or 5 half-lives, whichever is longer, before Visit 2 (topical agents with limited systemic availability are permitted). * Prior use of JAK inhibitors, systemic or topical, within the last 12 months. * Ultraviolet (UV) therapy or tanning within 2 weeks prior to Visit 2 or during the duration of the treatment period. * Any systemic or local infection that, in the opinion of the investigator, may compromise the safety of the subject or complicate assessments. * Subjects allergic to lidocaine or with a history of keloids will not be allowed to provide an optional skin biopsy, but will be eligible for the remainder of the study. * Electrocardiogram (ECG) changes on baseline screening consistent with high risk for a major adverse cardiovascular event (MACE).