The Bottom Line

DRESS syndrome (Drug Reaction with Eosinophilia and Systemic Symptoms) is a severe, potentially life-threatening drug reaction that affects not just the skin but also internal organs — most commonly the liver, kidneys, and heart. Unlike Stevens-Johnson Syndrome which appears in 1-3 weeks, DRESS has a characteristically delayed onset of 2-8 weeks after starting the causative medication. It requires immediate hospitalization, drug withdrawal, and often systemic corticosteroids. Mortality is 5-10%.

What Is DRESS Syndrome?

DRESS syndrome is a severe, systemic drug hypersensitivity reaction characterized by a widespread skin rash, high fever, swollen lymph nodes, elevated eosinophils (a type of white blood cell) in the blood, and internal organ damage — most commonly hepatitis (liver inflammation). It was previously known as drug-induced hypersensitivity syndrome (DIHS).

What makes DRESS particularly dangerous is its combination of skin AND organ involvement. While the rash itself is usually not as destructive as SJS/TEN (the skin doesn't peel off in sheets), the internal organ damage — particularly to the liver — can be severe and life-threatening. DRESS mortality is approximately 5-10%, primarily from liver failure, myocarditis (heart inflammation), or multi-organ failure.

A unique feature of DRESS is the frequent reactivation of herpes family viruses (HHV-6, HHV-7, CMV, EBV) during the reaction. This viral reactivation appears to amplify the immune response and contribute to organ damage, making DRESS a complex interplay between drug hypersensitivity, immune dysregulation, and viral reactivation.

Signs and Symptoms of DRESS

Timeline: DRESS characteristically appears 2-8 weeks (typically 3-6 weeks) after starting the causative drug — significantly later than most drug rashes. This delayed onset often makes the connection to the medication non-obvious.

Skin rash (present in >90%): Widespread, symmetrical morbilliform (measles-like) rash starting on the face and upper trunk, spreading downward. The rash may become edematous (puffy), infiltrated, or develop purplish discoloration. Facial swelling (facial edema) is very characteristic of DRESS and helps distinguish it from other drug eruptions.

Systemic symptoms: High fever (often 38-40°C/100.4-104°F), lymphadenopathy (swollen lymph nodes in multiple areas), sore throat, and malaise.

Organ involvement (the dangerous part):

  • Liver (most common, ~60-80%): Hepatitis ranging from mild elevation of liver enzymes to fulminant liver failure. This is the most common cause of death in DRESS.
  • Kidneys (~10-30%): Interstitial nephritis causing elevated creatinine and reduced kidney function.
  • Heart (~2-5% but serious): Myocarditis (heart inflammation) — can cause heart failure and is the second most common cause of death.
  • Lungs: Pneumonitis (lung inflammation) with cough and shortness of breath.
  • Thyroid: Autoimmune thyroiditis — may appear weeks to months after the acute DRESS episode (a delayed complication).

Blood abnormalities: Eosinophilia (elevated eosinophils — present in ~60-70%), atypical lymphocytes (resembling mononucleosis), and sometimes thrombocytopenia (low platelets).

What Causes DRESS Syndrome?

Most common causative medications:

  • Anticonvulsants: Carbamazepine, phenytoin, phenobarbital, lamotrigine — the most commonly implicated drug class
  • Allopurinol: A frequent cause, especially in patients with the HLA-B*5801 gene variant
  • Sulfonamide antibiotics: Trimethoprim-sulfamethoxazole (Bactrim)
  • Dapsone: Used for dermatitis herpetiformis and other conditions
  • Minocycline: A tetracycline antibiotic used for acne
  • Vancomycin: An IV antibiotic
  • Antiretrovirals: Abacavir, nevirapine

Viral reactivation component: HHV-6 reactivation is detected in 40-60% of DRESS cases. This viral reactivation is thought to amplify the immune response, contribute to organ damage, and may explain why DRESS can worsen or flare even after the drug is stopped — the viral reactivation sustains the immune activation.

Treatment for DRESS Syndrome

Immediate steps:

  1. Stop the causative drug immediately — this is essential
  2. Hospital admission for monitoring of organ function
  3. Baseline and serial blood tests: Liver function, kidney function, complete blood count with differential, cardiac enzymes

Medical management:

  • Systemic corticosteroids: Prednisone 1-2 mg/kg/day for moderate-to-severe cases, especially with significant organ involvement. Must be tapered slowly over 6-12 weeks — rapid taper can trigger DRESS relapse.
  • Supportive care: IV fluids, fever management, skin care (emollients for dry, peeling skin)
  • Organ-specific treatment: Hepatology consultation for liver involvement, nephrology for kidney involvement, cardiology if myocarditis is suspected
  • For severe/refractory cases: Cyclosporine, IVIG, or antiviral agents (ganciclovir for active HHV-6 reactivation)

Recovery and monitoring: DRESS typically resolves over weeks to months, but complications can appear late. Thyroid function should be monitored for 6-12 months after the episode (autoimmune thyroiditis is a known delayed sequela). Liver function should be monitored until fully normalized. Steroid taper must be gradual — DRESS commonly relapses with rapid steroid withdrawal.

When to See a Dermatologist

DRESS is typically diagnosed and managed in a hospital setting. Seek emergency medical care if you develop a widespread rash with fever 2-8 weeks after starting a new medication, especially if accompanied by facial swelling, sore throat, and swollen lymph nodes. After recovery, follow up with a dermatologist and allergist for drug allergy documentation — the causative drug and its chemical relatives must be permanently avoided.

Frequently Asked Questions

How is DRESS different from Stevens-Johnson Syndrome?

Both are severe drug reactions, but they are fundamentally different conditions. SJS causes skin blistering and peeling (epidermal necrosis) with mucous membrane involvement. DRESS causes a widespread morbilliform rash with facial edema and internal organ damage (especially liver). SJS appears at 1-3 weeks; DRESS appears at 2-8 weeks. SJS skin is the primary danger; in DRESS, organ involvement (liver failure, myocarditis) is the primary danger.

Why does DRESS take so long to appear after starting a drug?

The 2-8 week latency period reflects the time needed for the immune system to develop the specific hypersensitivity response AND for viral reactivation (HHV-6) to occur. This delayed onset is actually a diagnostic clue — most simple drug rashes appear within 1-2 weeks. If a rash with fever and organ involvement appears 3-6 weeks after starting a new medication, DRESS should be high on the differential diagnosis.

Can DRESS come back after it resolves?

DRESS can relapse during corticosteroid taper (if tapered too quickly) or if the patient is re-exposed to the causative drug or a chemically related drug. The causative drug must be permanently avoided. Cross-reactivity between related drugs (e.g., between aromatic anticonvulsants: carbamazepine, phenytoin, phenobarbital) means that if one caused DRESS, the others should also be avoided.

What is the thyroid connection with DRESS?

Autoimmune thyroiditis (Hashimoto's or Graves' disease) develops in 5-15% of DRESS patients, typically appearing weeks to months after the acute episode resolves. This is thought to be triggered by the immune dysregulation during the DRESS episode. Thyroid function (TSH) should be monitored every 3 months for at least a year after DRESS to catch this complication early.

References

  1. Cacoub P, Musette P, Descamps V, et al. The DRESS syndrome: a literature review. Am J Med. 2011;124(7):588-597.
  2. Kardaun SH, Sekula P, Valeyrie-Allanore L, et al. Drug reaction with eosinophilia and systemic symptoms (DRESS): an original multisystem adverse drug reaction. Br J Dermatol. 2013;169(5):1071-1080.
  3. Shiohara T, Inaoka M, Kano Y. Drug-induced hypersensitivity syndrome (DIHS): a reaction induced by a complex interplay among herpesviruses and antiviral and antidrug immune responses. Allergol Int. 2006;55(1):1-8.
  4. Husain Z, Reddy BY, Schwartz RA. DRESS syndrome. J Am Acad Dermatol. 2013;68(5):693.e1-693.e14.

Trusted Resources

  • American Academy of Dermatology Association. "Drug Reactions." aad.org
  • National Organization for Rare Disorders. "DRESS Syndrome." rarediseases.org
  • DermNet NZ. "DRESS Syndrome." dermnetnz.org

DRESS syndrome requires hospital management. If you develop a widespread rash with fever and facial swelling weeks after starting a new medication, seek emergency care immediately.