A 23-year-old man had small desquamative erythematous lesions, round or oval in shape, spread over his entire body, and diagnosed as psoriasis guttate acuta because of clinical and pathological findings. Three weeks before the lesions had started, he was diagnosed as having varicella by his family physician. The psoriatic lesions appeared at the same sites where previously lesions of varicella had appeared. Therefore, VZV infection was regarded as a trigger in this case. We speculate that genetic factors and the change of skin condition are basically involved in the pathogenesis of psoriasis guttate. In addition, one more factor as a trigger is needed to cause the lesions of psoriasis. VZV infection might change the skin condition and induce subsequent immunological disregulation.