Investigation of 92 patients with discoid lupus erythematosus, manifested initially by localized cutaneous lesions only, showed abnormal laboratory test results for 57 patients (62%) on admission and for 62 patients (67.4%) on review 16 to 20 years later. Patients with discoid lesions confined to the head and neck (DLE) showed fewer laboratory abnormalities than those patients with disseminated lesions involving trunk and limbs (disseminated discoid lupus erythematosus [DDLE]). Systemic lupus erythematosus (SLE) eventually developed in six (6.5%) of the patients, and all had shown persistent multiple abnormal laboratory findings from the beginning. Complete remission occurred in 46.7%. A persistent positive antinuclear factor of either speckled or homogeneous pattern with a titer greater than 1:50, leukopenia, thrombocytopenia, or a false-positive Wassermann reaction indicated those patients who may progress to DDLE or SLE.