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DRESS Syndrome – A Patient‑Friendly Medical Guide

Overview

DRESS syndrome (Drug Reaction with Eosinophilia and Systemic Symptoms) is a severe, potentially life‑threatening hypersensitivity reaction to certain medications. It is characterized by a triad of skin eruption, marked eosinophilia (high eosinophil count), and involvement of internal organs such as the liver, kidneys, lungs, or heart.

• Typical age: Most cases occur in adults (median age 30–55 years), but children and the elderly can be affected.
• Gender: Slight female predominance (≈ 55–60 %).
• Prevalence: Rare – estimated 1–3 cases per 1 000 000 population per year, but the incidence rises to 1 %–2 % among users of high‑risk drugs such as carbamazepine or allopurinol.<sup>1</sup>

DRESS syndrome usually appears 2–8 weeks after the culprit drug is started, which distinguishes it from more immediate drug eruptions. Early recognition and prompt treatment dramatically improve outcomes.

Symptoms

Symptoms develop gradually and often begin with nonspecific systemic signs before the rash becomes apparent.

General / Systemic Symptoms

• Fever (≥38 °C/100.4 °F) in > 90 % of cases.
• Generalized malaise, fatigue, and myalgia.
• Weight loss or anorexia.
• Lymphadenopathy (enlarged lymph nodes), usually cervical, axillary, or inguinal.

Cutaneous (Skin) Manifestations

• Diffuse morbilliform rash: Red, maculopapular eruption that can cover > 50 % of body surface.
• Facial edema: Puffiness especially around the eyes.
• Target or erythema multiforme‑like lesions: May appear on palms, soles, or trunk.
• Desquamation: Skin sloughing after 2–3 weeks, similar to Stevens‑Johnson syndrome but usually less extensive.
• Pruritus or burning sensation.

Hematologic Findings

• Eosinophilia (≥1.5 × 10⁹/L) – a hallmark; may exceed 5 × 10⁹/L.
• atypical lymphocytes.
• Thrombocytopenia or neutropenia (less common).

Organ Involvement (Systemic Symptoms)

At least one internal organ is usually affected. The most frequent sites are:

• Liver: Hepatitis, ↑ transaminases (ALT/AST), bilirubin elevation; severe cases can evolve to fulminant liver failure.
• Kidneys: Interstitial nephritis, acute kidney injury.
• Lungs: Pneumonitis, pleural effusion, or acute respiratory distress.
• Heart: Myocarditis or pericarditis (rare but high mortality).
• Thyroid: Autoimmune thyroiditis may develop weeks to months later.

Causes and Risk Factors

DRESS is not caused by a single drug; rather, it is an idiosyncratic immune reaction to a class of medications.

Common Culprit Drugs

• Anticonvulsants – carbamazepine, phenytoin, lamotrigine, phenobarbital.
• Allopurinol (used for gout).
• Sulfonamide antibiotics – sulfamethoxazole/trimethoprim, sulfasalazine.
• Minocycline (tetracycline class).
• Some antivirals (e.g., abacavir) and antiretrovirals.
• Non‑steroidal anti‑inflammatory drugs (NSAIDs) – rare but reported.

Genetic Predisposition

• Specific HLA alleles increase risk. For example, HLA‑B*58:01 is strongly associated with allopurinol‑induced DRESS in Asian and European populations.<sup>2</sup>
• HLA‑A*31:01 and HLA‑B*15:02 have been linked to carbamazepine reactions.

Other Risk Factors

• Previous drug hypersensitivity or severe cutaneous adverse reactions (SCARs).
• Poly‑pharmacy – taking several high‑risk drugs concurrently.
• Viral reactivations (HHV‑6, EBV, CMV) appear to amplify the immune response; they are often detected during the acute phase.<sup>3</sup>
• Impaired hepatic or renal function may alter drug metabolism, increasing toxic metabolites.

Diagnosis

DRESS diagnosis is clinical, supported by laboratory and histopathologic data. No single test definitively confirms the condition, so clinicians use validated scoring systems.

Diagnostic Criteria

• RegiSCAR (European Registry of Severe Cutaneous Adverse Reactions) score: Assigns points for fever, enlarged lymph nodes, eosinophilia, atypical lymphocytes, skin rash extent, organ involvement, and exclusion of alternative diagnoses. A score ≥5 = “definite” DRESS.<sup>4</sup>
• Bocquet criteria (France): Requires three of the following: skin eruption, eosinophilia, systemic involvement, and drug exposure with a latency of 2‑6 weeks.

Laboratory Tests

• Complete blood count – eosinophilia, atypical lymphocytes.
• Liver panel – ALT, AST, bilirubin, alkaline phosphatase.
• Renal function – serum creatinine, BUN.
• Inflammatory markers – ESR, CRP (often elevated).
• Viral PCR for HHV‑6, EBV, CMV (helps explain severity, may guide antiviral therapy).
• Serology for autoantibodies if autoimmune sequelae are suspected.

Imaging & Organ‑Specific Tests

• Chest X‑ray or CT scan if pulmonary symptoms.
• Abdominal ultrasound or MRI for hepatic involvement.
• Echocardiogram when cardiac symptoms or elevated troponin appear.

Skin Biopsy

Not mandatory but can support diagnosis. Typical findings: interface dermatitis, eosinophilic infiltrate, and necrotic keratinocytes. Helps to exclude other drug eruptions or infectious exanthems.

Exclusion of Mimickers

Important differentials include Stevens‑Johnson syndrome/toxic epidermal necrolysis (SJS/TEN), acute viral exanthems, autoimmune lupus, and drug‑induced hypersensitivity vasculitis.

Treatment Options

Managing DRESS is a multidisciplinary effort involving dermatology, internal medicine, and sometimes intensive care. The primary goals are to stop the offending drug, control inflammation, and support affected organs.

Immediate Measures

• Discontinue the suspect drug: The most crucial step; substitute with an alternative if needed (e.g., use febuxostat instead of allopurinol).
• Document the reaction in the patient’s electronic health record and provide a drug‑allergy card.

Systemic Corticosteroids

• First‑line therapy – oral prednisone 1 mg/kg/day (or equivalent). Intravenous methylprednisolone may be used for severe organ involvement.
• Taper slowly over 6‑12 weeks to prevent relapse; abrupt cessation can cause recurrence of symptoms.
• Monitoring: blood pressure, glucose, and signs of infection.

Steroid‑Sparing Agents (for steroid‑refractory or relapse cases)

• Cyclosporine: 2–5 mg/kg/day divided twice daily; acts on T‑cell activation.
• Intravenous immunoglobulin (IVIG):** 2 g/kg total over 2–5 days – useful in severe skin involvement or when steroids contraindicated.
• Mycophenolate mofetil, azathioprine, or tacrolimus: Considered in chronic or relapsing disease.

Antiviral Therapy

If HHV‑6 reactivation is documented and the patient has severe organ damage, short‑course ganciclovir or valganciclovir may be added, though evidence is limited.<sup>5</sup>

Supportive Care

• Fluid and electrolyte management, especially if fever and skin loss cause dehydration.
• Topical emollients, mild corticosteroid creams for itching (avoid high‑potency steroids on large areas).
• Antipyretics (acetaminophen) for fever – avoid NSAIDs due to cross‑reactivity.
• Monitoring of organ function: daily liver enzymes, creatinine, and CBC during the acute phase.

When Hospitalization Is Needed

• Extensive skin involvement (>30 % BSA) or rapid progression.
• Elevated transaminases >5 × upper limit of normal, rising creatinine, or pulmonary infiltrates.
• Hemodynamic instability, fever >39 °C, or any sign of multi‑organ failure.

Living with DRESS Syndrome

Survivors often face lingering issues; education and follow‑up are essential.

Follow‑up Schedule

• First month: clinic visit every 1–2 weeks for labs and symptom check.
• Months 2–6: monthly visits, focusing on liver/kidney recovery and tapering steroids.
• After 6 months: quarterly visits for at least 1 year, then annually.

Medication Management

• Carry a medical alert bracelet listing “DRESS syndrome – avoid: carbamazepine, allopurinol, sulfonamides, etc.”
• Maintain an updated medication list and share with every new prescriber.
• Consider pharmacogenetic testing (HLA‑B*58:01, HLA‑A*31:01) before restarting high‑risk drugs.

Lifestyle Adjustments

• Stay well‑hydrated; aim for ≥ 2 L water daily unless fluid‑restricted.
• Balanced diet rich in antioxidants (fruits, vegetables) to support hepatic recovery.
• Avoid alcohol and hepatotoxic over‑the‑counter supplements while liver enzymes are abnormal.
• Use gentle, fragrance‑free skin cleansers; moisturize after bathing to maintain barrier function.
• Practice stress‑reduction techniques (mindfulness, yoga) – stress can exacerbate immune dysregulation.

Psychological Support

The abrupt, severe nature of DRESS can lead to anxiety or depression. Referral to a mental‑health professional and participation in support groups is advisable.

Prevention

Because DRESS is unpredictable, prevention focuses on minimizing exposure to known triggers and recognizing early warning signs.

• Pharmacogenetic screening: Test for HLA‑B*58:01 before prescribing allopurinol, especially in Asian, African, or Hispanic patients.
• Medication reconciliation: Review all current drugs before adding a new one; avoid unnecessary poly‑pharmacy.
• Educate patients: Explain the typical latency (2–8 weeks) and tell patients to report any fever, rash, or swelling promptly.
• Use the lowest effective dose: Some high‑risk drugs have dose‑related risk (e.g., minocycline > 100 mg/day).
• Alternative agents: When possible, choose drugs with a lower DRESS risk profile (e.g., febuxostat instead of allopurinol).

Complications

If not recognized early or inadequately treated, DRESS may lead to serious, sometimes irreversible damage.

• Hepatic failure: Leading cause of mortality; may require liver transplantation.
• Acute kidney injury: Can progress to chronic kidney disease.
• Multiorgan failure: Respiratory distress, myocarditis, or hematologic collapse.
• Persistent autoimmune disease: Thyroiditis, type 1 diabetes, or systemic lupus‑like syndrome developing months after the acute episode.
• Secondary infections: Due to immunosuppression from steroids or the disease itself.
• Relapse: Occurs in 10‑20 % of patients, especially after rapid steroid taper.

When to Seek Emergency Care

Call 911 or go to the nearest emergency department if you experience any of the following:

• Sudden high fever (> 39 °C / 102 °F) that does not respond to acetaminophen.
• Rapid swelling of the face, lips, tongue, or throat causing trouble breathing or swallowing.
• Severe chest pain, shortness of breath, or a rapid heartbeat.
• Yellowing of the skin or eyes (jaundice), dark urine, or pale stools indicating liver failure.
• Sudden drop in urine output, swelling of the legs, or confusion – signs of kidney or cardiac involvement.
• Rash that spreads quickly, blisters, or skin that tears easily (possible progression to SJS/TEN).

Prompt treatment can be lifesaving.

References

1. Centers for Disease Control and Prevention. Severe Cutaneous Adverse Reactions (SCARs). https://www.cdc.gov
2. Hung SI, et al. HLA‑B*58:01 allele and severe cutaneous adverse reactions to allopurinol. N Engl J Med. 2005;352:259–267.
3. Descamps V, et al. Reactivation of human herpesvirus 6 in DRESS syndrome. Clin Infect Dis. 2018;66:985‑991.
4. Sassolas B, et al. Validation of the RegiSCAR scoring system for DRESS. JAMA Dermatol. 2016;152(11):1231‑1238.
5. Picard A, et al. Antiviral therapy in HHV‑6 reactivation during DRESS. Ther Adv Drug Saf. 2020;11:2042098620916697.

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