A 35-year-old man with tuberculosis on anti-TB therapy develops high fever, widespread blistering, and skin detachment involving 35% of body surface area with severe mucosal involvement and systemic toxicity. Causative drug is identified and withdrawn. What is the preferred initial pharmacological intervention?

## Diagnosis and Clinical Context The presentation describes **Toxic Epidermal Necrolysis (TEN)** — the severe end of the SJS/TEN spectrum: - Involvement of ≥30% BSA (here 35%) - Widespread blistering and full-thickness epidermal detachment - Severe mucosal involvement - Systemic toxicity - Anti-TB drugs are a well-recognized cause (isoniazid, rifampicin, pyrazinamide) ### First-Line Therapy: IVIG **Key Point:** IVIG remains the gold-standard first-line immunomodulatory therapy for TEN, with the strongest evidence for halting progression and reducing mortality. **High-Yield:** Evidence for IVIG in TEN: - **Mortality reduction:** IVIG reduces TEN mortality from ~30% to ~15–20% when given early - **Mechanism:** Blocks Fas-FasL-mediated keratinocyte apoptosis; inhibits TNF-α, IL-6, and IL-10 - **Timing:** Most effective within 72 hours of diagnosis - **Dosing:** 2 g/kg total (0.4–0.5 g/kg daily × 3–5 days) ### Comparative Efficacy in TEN | Agent | Evidence Level | Mortality Impact | Role | |---|---|---|---| | **IVIG** | Level 1 (RCTs, meta-analyses) | ~50% reduction | **First-line** | | Systemic corticosteroids | Level 2–3; observational | Increased mortality | **Avoid** | | Cyclosporine | Level 2; case series | Modest benefit | Second-line | | Tacrolimus | Level 3; case reports | Unclear | Salvage | | Plasmapheresis | Level 3; anecdotal | No proven benefit | Not recommended | **Clinical Pearl:** TEN is a dermatological emergency with mortality rates of 25–35% if untreated. Early IVIG administration (within 72 hours) is associated with significantly better outcomes than delayed treatment or corticosteroids alone. **Warning:** Systemic corticosteroids in TEN are **contraindicated** — they increase sepsis risk, delay healing, and are associated with worse outcomes. This is a critical exam point. **Mnemonic: IVIG in TEN — "Fast, Fas-blocking, Fewer deaths"** - **Fast:** rapid onset of action - **Fas-blocking:** mechanism of action - **Fewer deaths:** proven mortality reduction ### Management Algorithm ```mermaid flowchart TD A[TEN Diagnosis: BSA ≥30%]:::outcome --> B[Withdraw offending drug immediately]:::action B --> C[IVIG 2 g/kg over 3-5 days]:::action C --> D{Response in 48-72 hrs?}:::decision D -->|Yes: Arrest of progression| E[Continue supportive care]:::action D -->|No: Continued spread| F[Add cyclosporine 3-5 mg/kg/day]:::action F --> G[ICU/burn unit care]:::action H[Avoid systemic corticosteroids]:::urgent ``` ### Supportive Care (Equally Critical) - ICU or specialized burn unit admission - Fluid resuscitation (Parkland formula adapted) - Ophthalmology, ENT, urology review - Infection prophylaxis (broad-spectrum antibiotics, antifungals) - Nutritional support - Pain management [cite:Harrison 21e Ch 56; Auquier-Dunant et al. Lancet 2002]