Dress Syndrome

What is Dress syndrome?

Dress syndrome is a severe delayed drug hypersensitivity reaction mediated largely by T cells. In this condition, immune cells overreact to drug antigens, leading to a complex systemic inflammatory response. For high-risk antiseizure medications, the incidence is estimated at approximately 1 in 1,000 to 1 in 10,000 exposures. Delayed recognition can lead to severe internal organ involvement, especially hepatitis, and DRESS carries a meaningful risk of mortality.

What causes Dress Syndrome?

High-risk medications include aromatic anticonvulsants such as phenytoin and carbamazepine, as well as lamotrigine, allopurinol, sulfonamide antibiotics, and dapsone. Unlike most drug eruptions, DRESS typically begins 2 to 8 weeks after starting the culprit medication. Herpesvirus reactivation, especially HHV-6, is commonly associated with DRESS, but its precise pathogenic role remains uncertain. Genetic factors also play a significant role; for example, the HLA-B*58:01 allele significantly increases susceptibility to the syndrome when taking allopurinol.

What are the signs and symptoms of Dress Syndrome?

The first signs of DRESS syndrome usually consist of high fever, malaise (a general feeling of discomfort), and a pruritic (itchy) rash. Facial edema—specifically swelling around the eyes—cervical lymphadenopathy (swollen neck lymph nodes), and hepatitis often follow as the eruption spreads across the body. Laboratory findings may include eosinophilia, often >700/µL, and atypical lymphocytes, although eosinophilia may be absent early or in some cases.

The cutaneous eruption is typically morbilliform, with erythematous macules and papules that may become confluent and later desquamate. Clinicians must distinguish dress syndrome vs stevens johnson syndrome; the latter is characterized by painful mucosal sloughing and rapid epidermal detachment, whereas eosinophilia and facial edema are more prominent in the former.

How is Dress Syndrome diagnosed?

The clinical history must identify any culprit drug exposures within the preceding 2 to 8 weeks and evaluate for possible viral reactivations. The RegiSCAR criteria for dress syndrome serve as the diagnostic standard, requiring a score based on fever ≥38.5°C, rash, lymphadenopathy, hematologic abnormalities, and internal organ involvement. Hematologic abnormalities, such as eosinophilia or atypical lymphocytes, are also essential components of the scoring system.

Initial evaluation includes a complete blood count with differential, liver and renal tests, and additional studies guided by suspected organ involvement; viral PCR or serologies may be considered in selected cases. While a skin biopsy is rarely required for diagnosis, it can help exclude mimics and show interface dermatitis, dermal edema, and eosinophilic infiltrates to support the clinical findings. Practitioners use these criteria for dress syndrome to exclude alternative explanations like sepsis or acute viral infections.

How is Dress Syndrome treated?

The most critical step in management is the immediate withdrawal of the offending drug to halt ongoing immune activation. Mild disease without major organ involvement can often be treated with topical corticosteroids and close monitoring, whereas moderate to severe disease is typically treated with systemic corticosteroids such as prednisone 0.5 to 1 mg/kg/day, tapered slowly over 8 to 12 weeks or longer. This taper is guided by the individual’s clinical response and laboratory trends to prevent a relapse of the rash or organ inflammation.

In cases with high-risk organ involvement, such as severe myocarditis or pneumonitis, specialists may add intravenous immunoglobulin (IVIG) or cyclosporine to further interrupt T-cell activation. Aggressive co-management of specific organ injuries, particularly the liver and kidneys, is a vital part of the dress syndrome treatment plan. Long-term follow-up is necessary to monitor for potential autoimmune sequelae that can develop months after the initial episode.

What are the most important facts to know about Dress Syndrome?

• Dress syndrome is a life-threatening, T-cell–mediated hypersensitivity reaction characterized by a long delay between drug exposure and symptom onset.
• Common triggers include anticonvulsants and allopurinol, with viral reactivation (especially HHV-6) acting as a major driver of inflammation.
• The first signs of dress syndrome include high fever and a widespread rash, often accompanied by facial swelling and lymph node enlargement.
• Diagnosis is supported by the RegiSCAR criteria for dress syndrome, which integrate physical findings with hematologic markers like eosinophilia.
• Dress syndrome treatment prioritizes the immediate withdrawal of the culprit drug, supportive care, and severity-based anti-inflammatory therapy.