A 38-year-old man with a history of tuberculosis presents to the hospital with a 7-day history of fever, widespread painful blistering eruption, and oral ulceration. He started anti-tuberculous therapy (isoniazid, rifampicin, pyrazinamide, ethambutol) 10 days ago. On examination, he has extensive erythematous patches and plaques with large flaccid bullae on his chest, abdomen, and thighs. Nikolsky sign is positive. Mucous membranes are extensively denuded. Skin biopsy shows near-total epidermal necrosis with minimal inflammatory infiltrate. Estimated body surface area involvement is 35%. What is the most appropriate next step in management?

Explanation

## Diagnosis: Toxic Epidermal Necrolysis (TEN) **Key Point:** This patient has Toxic Epidermal Necrolysis (TEN), not SJS. The defining feature is epidermal necrosis involving >30% of body surface area (this patient has 35% BSA involvement). Near-total epidermal necrosis with minimal inflammation on histology is pathognomonic for TEN. ### Distinguishing SJS from TEN | Feature | SJS | TEN | |---------|-----|-----| | **BSA involvement** | <10% | >30% | | **Mucosal involvement** | >90% | >90% | | **Histology** | Full-thickness epidermal necrosis, subepidermal blister | Near-total epidermal necrosis, minimal inflammation | | **Mortality** | 5–10% | 25–50% | | **Management urgency** | High | **CRITICAL** | **High-Yield:** TEN is a dermatologic emergency with mortality rates of 25–50% depending on age and organ involvement. This patient requires ICU-level care. ### Immediate Management of TEN 1. **Drug Withdrawal** — All potentially offending drugs must be stopped immediately. Isoniazid, rifampicin, and pyrazinamide are all known culprits in anti-TB regimens. 2. **Specialist Transfer** — Transfer to a burn unit or specialized dermatology ICU is mandatory. TEN patients require: - Intensive fluid and electrolyte management (losses equivalent to 30–50% BSA burn) - Nutritional support (often via nasogastric or parenteral nutrition) - Infection prevention (sterile technique, barrier nursing) - Temperature regulation - Ophthalmologic monitoring (prevent symblepharon, corneal scarring) 3. **Systemic Corticosteroids** — In TEN (unlike SJS), early high-dose systemic corticosteroids are indicated: - Start within 48 hours of onset (this patient is at day 7, but still within treatment window) - Typical regimen: methylprednisolone 1–2 g/day IV or equivalent - Evidence suggests corticosteroids reduce mortality and progression in TEN - Taper gradually as lesions stabilize 4. **Supportive Care** - IV fluid resuscitation (calculate using Parkland formula or similar) - Electrolyte monitoring and replacement - Pain control (opioids often required) - Prophylactic antibiotics (not therapeutic; infection is a major cause of death) - Nutritional support **Clinical Pearl:** TEN is a medical emergency with mortality comparable to severe thermal burns. The patient should be managed in an ICU with multidisciplinary input (dermatology, intensive care, ophthalmology, infectious disease). ### Why This Patient Requires Corticosteroids Unlike SJS, where corticosteroids are controversial, TEN with >30% BSA involvement has stronger evidence for benefit from early high-dose corticosteroids. The rationale: - Corticosteroids suppress the cytotoxic T-cell response driving keratinocyte apoptosis - Early administration (within 48–72 hours) may halt progression - In TEN, the risk-benefit favors treatment, as mortality without intervention is very high **Mnemonic: TEN-ALERT** — **T**emperature control, **E**lectrolytes, **N**utrition, **A**ntibiotics (prophylactic), **L**ung monitoring, **E**yes (ophthalmology), **R**enal function, **T**ransfer to ICU/burn unit. [cite:Harrison 21e Ch 56; Robbins 10e Ch 25]