We report an unusual case of disseminated discoid lupus erythematosus (DLE) complicated by pre-existing atopic dermatitis (AD) and late-onset Sjögren's syndrome (SS). Disseminated DLE lesions were sparse on the expected sites for AD, such as the medial region of the extremities or v-neck area. The patient fulfilled the diagnostic criteria for AD and SS but not for systemic lupus erythematosus. Histopathological analysis of the crusted erythematous lesions revealed typical DLE with few FoxP3(+) cells and a moderate number of IL-17(+) cells. A quantitative sweating test showed impaired sweating of both lesional and non-lesional skin due to underlying hypohidrosis that was related to AD and SS. This finding suggests that dissemination of DLE was triggered by scratching and a Köbner phenomenon-like effect related to hypohidrotic and xerotic skin. To the best of our knowledge, this is the first reported case of disseminated DLE complicated by AD and SS.