Abstract
Systemic lupus erythematosus is a chronic autoimmune disease often presenting with cutaneous symptoms such as malar rash. While hydroxychloroquine is standard therapy, some cases remain treatment-resistant. Molecular hydrogen possesses anti-inflammatory and immunomodulatory effects in autoimmune disorders. This case report examines the use of molecular hydrogen as adjunctive therapy in a 27-year-old woman with systemic lupus erythematosus and refractory malar rash. Despite hydroxychloroquine treatment, her rash persisted and significantly impacted the quality of life. After initiating oral molecular hydrogen therapy, the patient showed sustained clinical improvement, including reduced malar rash, decreased fatigue, and enhanced well-being over several months. These outcomes were accompanied by notable immunological changes: increased killer cell lectin-like receptor G1 positive effector T cells, decreased plasmablast activity, stabilization of B cell exhaustion markers, and reductions in and a decline in antinuclear antibody and anti-double-stranded DNA antibody levels. This case suggests that molecular hydrogen may be a safe and promising adjunctive treatment for cutaneous manifestations and systemic immune modulation in systemic lupus erythematosus.