Exanthematic pustular psoriasis

Exanthematic Pustular Psoriasis (EPP), also known as Acute Generalized Pustular Psoriasis (AGPP), is a rare and severe form of psoriasis characterized by the widespread occurrence of sterile pustules on inflamed and erythematous skin. This condition represents a significant systemic inflammatory response and can be life-threatening if not promptly and effectively treated.

Etiology and Pathogenesis

The exact cause of Exanthematic Pustular Psoriasis remains unclear, but it is believed to be multifactorial, involving genetic predisposition, immune system dysregulation, and environmental triggers. Genetic factors play a crucial role, with certain alleles being associated with an increased risk of developing the disease. Environmental triggers such as infections, medications (e.g., lithium, antimalarials), and sudden withdrawal of systemic corticosteroids can precipitate the condition. The pathogenesis involves an exaggerated immune response leading to the rapid turnover of skin cells and the formation of pustules.

Clinical Features

EPP is characterized by the sudden onset of widespread, painful, erythematous skin covered with numerous sterile pustules. The skin changes are often accompanied by systemic symptoms such as fever, malaise, and arthralgia. The lesions typically start in the flexural areas and rapidly become generalized. The Nikolsky sign may be positive in areas of skin involvement. Laboratory findings include elevated inflammatory markers (e.g., C-reactive protein), leukocytosis with neutrophilia, and occasionally, hypoalbuminemia and electrolyte imbalances.

Diagnosis

The diagnosis of Exanthematic Pustular Psoriasis is primarily clinical, supported by the history, physical examination, and the exclusion of other causes of acute pustular eruptions. Skin biopsy can be helpful in confirming the diagnosis, showing spongiform pustules of Kogoj and subcorneal pustules of Munro. Histopathology typically reveals neutrophilic infiltration and edema in the papillary dermis.

Treatment

Management of EPP requires a multidisciplinary approach and often involves hospitalization. Initial treatment focuses on supportive care, including fluid and electrolyte management, temperature regulation, and nutritional support. Systemic therapies are essential for controlling the disease activity and may include corticosteroids, cyclosporine, methotrexate, and biologic agents such as TNF inhibitors. The choice of therapy depends on the severity of the disease, patient comorbidities, and response to previous treatments. Early and aggressive treatment is crucial to prevent complications and improve outcomes.

Prognosis

The prognosis of Exanthematic Pustular Psoriasis varies. With prompt and appropriate treatment, patients can achieve remission. However, the disease may recur, and chronic, recurrent episodes are not uncommon. Complications such as secondary infections, sepsis, and multi-organ failure can occur, especially in untreated or inadequately treated cases, and may be life-threatening.

Prevention

Preventive measures for EPP include the avoidance of known triggers, careful management of medications, and regular follow-up with healthcare providers to monitor for early signs of disease activity. Patients with a history of EPP should be educated about the potential triggers and the importance of early treatment initiation at the onset of symptoms.