Annular pustular psoriasis--most common form of pustular psoriasis in children: report of three cases and review of the literature.

Annular pustular psoriasis (APP) is a rare form of pustular psoriasis with a chronic recurrent course and good prognosis. We report three cases of APP in children, two of whom were siblings. Review of the medical literature reveals that a disproportionately high percentage of cases of APP occur in children. In some cases topical therapy can clear the condition, although in severe or recalcitrant disease, systemic therapy may be necessary.