Generalized Pustular Psoriasis: a New Emerging Concept Relating to Autoinflammatory Disease

Generalized Austular Asoriasis (GPP) is a rare systemic inflammatory disease characterized by widespread, superficial sterile pustules over the trunk, which often rapidly develop into erythroderma. Pustular psoriasis is divided into generalized and localized, and the former type includes Zumbusch type, Impetigo Herpetiformis (acute GPP of pregnancy), annular and circinate form, juvenile and infantile pustular psoriasis, and generalized form of acrodermatitis continua (Hallopeau). Annular pustular psoriasis is usually localized, but rarely develops generally with systemic manifestation such as high fever, chills, and systemic inflammation. Histologically, GPP demonstrates subcornealspongiform abscess, acanthosis, and cellular infiltrates in the papillary dermis. Neutrophils are supposed to be attracted by some chemotactic factors into the epidermis, such as Inter Leukin-8 (IL-8), Growth-Related Oncogene-alpha (GRO-α), CXCL2/Macrophage Inflammatory Protein-2 (MIP-2), LeukoTriene B4 (LTB4), Platelet Activating Factor (PAF), and C5a. Serum levels of IL-1, tumor necrosis factor-α (TNF-α), IL-6, IL-8, GRO-α, and soluble Fas are increased in patients with GPP, some of which correlate with clinical severities.