A 28-year-old man presents with fever, generalized lymphadenopathy, and a pruritic maculopapular rash over the trunk and extremities that began 3 weeks after starting phenytoin for newly diagnosed seizures. Laboratory investigations show WBC 12,000/μL with atypical lymphocytes, elevated transaminases (ALT 280 U/L), and mild thrombocytopenia. Which of the following is the most appropriate immediate management?

Explanation

## DRESS Syndrome: Clinical Recognition and Management ### Case Analysis This patient presents with the classic triad of DRESS syndrome (Drug Reaction with Eosinophilia and Systemic Symptoms): - **Temporal relationship:** Rash onset 3 weeks post-drug initiation (phenytoin is a well-known culprit) - **Systemic involvement:** Fever, lymphadenopathy, hepatic dysfunction - **Hematologic abnormalities:** Atypical lymphocytes, mild thrombocytopenia ### Pathophysiology DRESS syndrome is a severe, delayed hypersensitivity reaction (Type IV) characterized by: 1. Viral reactivation (HHV-6, EBV, CMV) in genetically predisposed individuals 2. T-cell mediated immune activation 3. Systemic inflammation affecting skin, lymph nodes, liver, and hematologic system ### Management Algorithm ```mermaid flowchart TD A[Clinical suspicion of DRESS]:::outcome --> B{Confirm diagnosis}:::decision B -->|RegiSCAR score ≥4| C[Probable/Definite DRESS]:::outcome C --> D[Discontinue offending drug immediately]:::action D --> E[Initiate systemic corticosteroids]:::action E -->|Mild-moderate| F[Prednisolone 0.5-1 mg/kg/day]:::action E -->|Severe| G[Methylprednisolone 1-2 mg/kg/day or IV pulse]:::action G --> H[Taper over 6-12 weeks]:::action H --> I[Monitor for relapse and viral reactivation]:::outcome ``` ### Key Management Principles **Key Point:** The cornerstone of DRESS management is **immediate discontinuation of the offending drug** combined with systemic corticosteroids. Continuing the causative agent while adding steroids does not address the underlying pathology and risks disease progression. **High-Yield:** Phenytoin, carbamazepine, allopurinol, and sulfonamides are the most common triggers in India. Aromatic antiepileptics carry the highest risk. **Clinical Pearl:** Atypical lymphocytes and hepatic involvement are hallmarks distinguishing DRESS from simple drug eruptions. The presence of lymphadenopathy with systemic symptoms mandates aggressive intervention. **Warning:** Do NOT switch to carbamazepine (Option 3) — it is structurally similar to phenytoin and carries cross-reactivity risk in ~25% of DRESS cases. This would likely precipitate recurrence or worsening. ### Why Discontinuation + Steroids? | Aspect | Rationale | |--------|----------| | **Drug withdrawal** | Removes the antigenic trigger and prevents continued immune activation | | **Corticosteroids** | Suppress T-cell activation, reduce cytokine production, and control systemic inflammation | | **Timing** | Early intervention (within days of diagnosis) prevents progression to multi-organ failure | ### Dosing and Duration - **Initial dose:** Prednisolone 0.5–1 mg/kg/day (or methylprednisolone 1–2 mg/kg/day for severe cases) - **Taper:** Gradual reduction over 6–12 weeks to prevent rebound flares - **Monitoring:** Weekly LFTs and CBC for the first month, then monthly ### Prognosis - **Mortality:** 10–15% if untreated; <1% with early recognition and corticosteroids - **Relapse:** 20–30% of cases show flares during steroid taper — requires dose adjustment [cite:Robbins 10e Ch 25]