Slide show: Types of psoriasis

Pustular psoriasis can occur in widespread patches or in smaller areas on your hands, fingertips or feet, as shown here. It can develop quickly, with pus-filled blisters appearing just hours after your skin becomes red and tender. The blisters clear up within several days, but recur. Possible causes include medication withdrawal and infection.

Small patches of pustular psoriasis may be treated with a steroid cream. Larger patches usually require prescription oral medication, elimination of the underlying cause, if possible, and other topical and systemic therapies. Light therapy may be useful once the blisters resolve and the skin is less irritated.