Generalized pustular psoriasis

Generalized pustular psoriasis is a rare type of psoriasis that usually covers the whole body with pus-filled blisters rather than the plaques of common psoriasis. It can appear at any age, is rarer in young children, can arise with or without earlier psoriasis and can recur in episodes. Patients are often feverish and systemically ill, and the hallmark is sheets of pinhead-sized, sterile pustules beneath the outer skin layer, often at the edges of expanding inflamed plaques or within erythrodermic skin. Many cases follow a trigger: corticosteroid withdrawal is the commonest precipitant in people with earlier psoriasis and infection in those without. Mutations in the IL36RN, CARD14 and AP1S3 genes have been shown to cause it. Several forms exist, including von Zumbusch acute generalized pustular psoriasis, and one form can change into another or several can occur together.