Acute Generalized Exanthematous Pustulosis and Generalized Pustular Psoriasis

Clinical Characteristics

The American Academy of Dermatology notes that Generalized Pustular Psoriasis (GPP) is a chronic inflammatory disease that requires long-term systemic therapy, whereas Acute Generalized Exanthematous Pustulosis (AGEP) is an acute, self-limiting condition that resolves rapidly after withdrawal of the offending drug 1
GPP can evolve from chronic plaque psoriasis or present acutely with minimal pre-existing psoriasis, and its development is more gradual compared to AGEP 1
The presence of systemic symptoms such as fever and toxicity, and the risk of metabolic complications and mortality, necessitate hospitalization for GPP 2

The American Academy of Dermatology recommends that the diagnosis of GPP is primarily clinical, with findings including fever, systemic toxicity, pustules on an erythematous background, and evidence of classic plaque psoriasis 1, 3
A skin biopsy may be necessary to confirm the diagnosis in atypical presentations of both AGEP and GPP 3

The American Academy of Dermatology suggests that the first-line treatment for GPP includes spesolimab, an anti-IL-36 receptor antibody, and other systemic alternatives such as acitretin, cyclosporine, and methotrexate 3, 4
Biologics like infliximab are also considered a first-line biologic therapy for GPP, with a standard dosing regimen 2, 4
The use of systemic corticosteroids is absolutely contraindicated in GPP due to the risk of precipitating erythrodermic psoriasis, GPP, or very unstable psoriasis upon withdrawal, potentially leading to fatal deterioration 2, 4

Regular clinical review is necessary for all patients with GPP undergoing treatment, along with essential monitoring including regular blood tests, liver function tests, and serum creatinine depending on the agent used 3, 4
Monitoring for complications such as secondary infections, metabolic abnormalities, and systemic inflammation is also crucial 3
Recurrence is common but not universal after discontinuation of biologics in GPP 4

Generalized pustular psoriasis (GPP) pustules develop on an erythematous background and are frequently associated with classic plaque‑type psoriasis lesions that may be present before, during, or after the pustular flare. 5
GPP typically lacks significant mucosal involvement, whereas AGEP can show mild, non‑erosive oral lesions. 5

Both AGEP and GPP commonly present with fever, neutrophilia, and systemic toxicity. 5

Infliximab is recommended as a first‑line biologic therapy for GPP, offering rapid efficacy and often achieving complete disease clearance. 6