Unilateral eruptive psoriasis and lichen striatus.

A 2-year-old boy experienced lichen striatus localized to the left half of the body. Some weeks later he developed a peculiar form of eruptive psoriasis limited to the right half of the body. To our knowledge, unilateral eruptive psoriasis has never been described in the literature. The coincidence in this young patient of lichen striatus and this unusual form of psoriasis arising in so short a period of time leads us to hypothesize a common trigger factor.