Drug reaction with eosinophilia and systemic symptoms

Severe drug-induced hypersensitivity reaction

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe, potentially life-threatening drug-induced hypersensitivity reaction. It is characterized by a combination of fever, rash, lymphadenopathy, hematological abnormalities, and internal organ involvement. The condition is also known as drug-induced hypersensitivity syndrome (DIHS).

Clinical Features

DRESS syndrome typically presents 2 to 8 weeks after exposure to the offending drug. The hallmark features include:

• Fever: Often high-grade and persistent.
• Rash: A widespread, morbilliform or maculopapular rash that may progress to exfoliative dermatitis.
• Lymphadenopathy: Swelling of lymph nodes, particularly in the cervical region.
• Hematological abnormalities: Eosinophilia is a key feature, but leukocytosis and atypical lymphocytes may also be present.
• Internal organ involvement: Hepatitis is the most common, but nephritis, pneumonitis, myocarditis, and thyroiditis can also occur.

Pathophysiology

The exact mechanism of DRESS is not fully understood, but it is believed to involve a complex interplay of genetic, immunological, and metabolic factors. Genetic predispositions, such as certain HLA alleles, have been associated with increased risk. The reactivation of human herpesvirus 6 (HHV-6) and other herpesviruses is also implicated in the pathogenesis.

Common Offending Drugs

Several drugs have been implicated in DRESS syndrome, including:

• Anticonvulsants: Such as phenytoin, carbamazepine, and lamotrigine.
• Antibiotics: Such as sulfonamides and minocycline.
• Allopurinol: Commonly used for gout management.
• Nonsteroidal anti-inflammatory drugs (NSAIDs): Such as celecoxib.

Diagnosis

The diagnosis of DRESS is primarily clinical, supported by laboratory findings. Criteria for diagnosis include:

• Exposure to a high-risk drug.
• Fever, rash, and lymphadenopathy.
• Hematological abnormalities, particularly eosinophilia.
• Evidence of internal organ involvement.

Management

The cornerstone of DRESS management is the immediate cessation of the offending drug. Supportive care and monitoring are crucial. Corticosteroids are often used to control severe symptoms, although their use is based on clinical judgment. In cases of severe organ involvement, more aggressive immunosuppressive therapy may be required.

Prognosis

The prognosis of DRESS can vary. While many patients recover completely with appropriate management, the condition can be fatal if not recognized and treated promptly. Long-term sequelae, such as thyroid dysfunction, may occur.

Related pages

• Hypersensitivity
• Eosinophilia
• Drug allergy
• Human herpesvirus 6