Pustular psoriasis: pathophysiology and current treatment perspectives

Abstract

Psoriasis vulgaris is a chronic inflammatory disease that classically affects skin and joints and is associated with numerous comorbidities. There are several clinical subtypes of psoriasis including the uncommon pustular variants, which are subdivided into generalized and localized forms. Generalized forms of pustular psoriasis include acute generalized pustular psoriasis, pustular psoriasis of pregnancy, and infantile and juvenile pustular psoriasis. Localized forms include acrodermatitis continua of Hallopeau and palmoplantar pustular psoriasis. These subtypes vary in their presentations, but all have similar histopathologic characteristics. The immunopathogenesis of each entity remains to be fully elucidated and some debate exists as to whether these inflammatory pustular dermatoses should be classified as entities distinct from psoriasis vulgaris. Due to the rarity of these conditions and the questionable link to the common, plaque-type psoriasis, numerous therapies have shown variable results and most entities remain difficult to treat. With increasing knowledge of the pathogenesis of these variants of pustular psoriasis, the development and use of biologic and other immunomodulatory therapies holds promise for the future of successfully treating pustular variants of psoriasis.

Keywords: acrodermatitis continua of Hallopeau; biologic; generalized pustular psoriasis; impetigo herpetiformis; palmoplantar pustulosis; psoriasis; pustular psoriasis; von Zumbusch.

Figure 1

Generalized pustular psoriasis. Notes: Innumerable pustules studded on a background of erythematous plaques on the chest, abdomen, and upper arms. Some areas of pustules have coalesced into large plaques of crust on the lower abdomen. Used with permission of Professor Alan Menter, Baylor University Medical Center.

Figure 2

Palmoplantar pustular psoriasis. Notes: (A, B) Multiple pustules studded on the palmar surface of the hands with a few areas of erythematous desquamative changes. (C, D) Innumerable pustules and small areas of hyperpigmentation in areas of prior pustules noted on the plantar feet with desquamation and mild erythema. Used with permission of Professor Alan Menter, Baylor University Medical Center.

Figure 3

Acrodermatitis continua of Hallopeau. Note: Erythematous plaques, hyperkeratosis, and pustules confined to the distal tips of all digits with nail involvement. Used with permission of Professor Alan Menter, Baylor University Medical Center.