Targeting TYK2 in Cutaneous Autoimmunity: Deucravacitinib-Induced Remission of Discoid Lupus and Psoriasis with Supportive Confocal Microscopy Findings

INTRODUCTION: Cutaneous lupus erythematosus (CLE), particularly discoid lupus erythematosus (DLE), is a chronic autoimmune condition driven in part by type I interferon signaling. No systemic therapies are specifically approved for CLE, and management is often extrapolated from systemic lupus erythematosus. Deucravacitinib, a selective oral tyrosine kinase 2 (TYK2) inhibitor targeting the Janus kinase (JAK)-signal transducer and activator of transcription (STAT) pathway, has shown efficacy in psoriasis and emerging promise in lupus. CASE REPORT: We describe a 29-year-old woman with biopsy-proven DLE refractory to prednisone and hydroxychloroquine who subsequently developed moderate-to-severe plaque psoriasis (Psoriasis Area and Severity Index [PASI] 16). Initial treatment with ixekizumab improved psoriasis but failed to control DLE, and psoriatic lesions later relapsed. Therapy was switched to deucravacitinib 6 mg daily. After 9 weeks, marked improvement of both conditions was observed (PASI 0.2) with progressive regression of DLE lesions. By week 27, complete clinical remission of psoriasis (PASI 0) and full resolution of DLE lesions were achieved, confirmed by reflectance confocal microscopy. CONCLUSION: This case highlights the potential of deucravacitinib as an effective therapeutic option for refractory DLE, particularly in patients with concomitant psoriasis, supporting TYK2 inhibition as a promising targeted strategy in cutaneous autoimmunity.