Methods: For CLE or SLE patients with lupus-associated skin lesions scoring >=4 on the Revised Cutaneous Lupus Erythematosus Disease Area and Severity Index (RCLASI) that have been refractory to the treatment of HCQ plus low-dose corticosteroids (<=0.5 mg/kg/d) during the past two months, oral nicotinamide (500 mg twice daily) will be given consecutively for 3 months while the current regimen including HCQ and corticosteroids be maintained without change. The end points include clinical response and immunological changes, as well as safety.