Toxic Epidermal Necrolysis (TEN) is a severe, acute, life-threatening mucocutaneous reaction characterized by widespread epidermal necrosis and detachment, involving more than 30% of body surface area.

It is most commonly triggered by medications and represents the severe end of the spectrum of Stevens–Johnson Syndrome (SJS)/TEN.

HIV infection significantly increases the risk of developing TEN. Mortality rate: 25–40%, depending on severity and complications.

Etiology (Common Causes)

Drugs (most common cause)

• Sulfonamides

• Anticonvulsants (carbamazepine, phenytoin, phenobarbital)

• Allopurinol

• Nevirapine

• NSAIDs (oxicam group)

• Penicillins and cephalosporins

Others

• Mycoplasma infection (rare in TEN)

• Vaccines (rare)

• Idiopathic

Pathophysiology

• Immune-mediated hypersensitivity reaction

• Massive keratinocyte apoptosis

• Cytotoxic T-cell–mediated epidermal destruction

• Leads to full-thickness epidermal necrosis

The skin separates at the dermo-epidermal junction → resembles severe burns.

Risk Factors

• HIV infection

• Polypharmacy

• Previous drug allergy

• Genetic predisposition

• Malignancy

• Autoimmune disease

Signs & Symptoms

A. Prodromal Phase (1–3 days before rash)

• Fever

• Malaise

• Sore throat

• Stinging/burning eyes

• Painful swallowing

B. Cutaneous Phase

• Sudden appearance of diffuse macules or erythema

• Early involvement:

  • Presternal trunk

  • Face

  • Palms and soles

• Rapid progression to blistering

• Epidermal detachment

• Skin peels in sheets (positive Nikolsky sign)

• Skin lies in folds on bedding

C. Mucosal Involvement (>90%)

• Buccal mucosa erosions

• Genital erosions

• Ocular involvement (conjunctivitis, erosions)

• Respiratory tract involvement

• Gastrointestinal mucosal erosions

Diagnostic Criteria

Clinical diagnosis based on:

• Prodrome: fever, eye irritation, dysphagia

• Sudden diffuse erythema or macules

• Early trunk and facial involvement

• Mucosal erosions (oral, genital, ocular)

• Rapid progression with widespread epidermal peeling

• Skin detachment >30% body surface area

Investigations

Laboratory tests

• Full blood count (anemia, leukopenia)

• Electrolytes (monitor imbalance)

• Urea & creatinine (renal function)

• Liver function tests

• Blood glucose

• Blood cultures (if sepsis suspected)

Other tests

• Skin biopsy (confirms full-thickness epidermal necrosis)

• Swabs for secondary infection

• Urinalysis

Severity scoring

• SCORTEN score (predicts mortality)

Management

A. Immediate Actions

• Stop suspected drug immediately

• Admit to high-dependency unit or burn unit

• Multidisciplinary care (dermatology, ophthalmology, ICU)

B. Non-Pharmacological Treatment

Supportive Care (Cornerstone of Treatment)

1. Fluid and electrolyte management

   • Monitor urine output

   • Target: 50–80 mL/hour

2. Wound care

   • Conservative management

   • Do NOT perform aggressive debridement

   • Use sterile non-adherent dressings

3. Temperature regulation

4. Nutritional support (high protein diet)

5. Pain control

6. Infection prevention (aseptic handling)

C. Pharmacological Treatment

1. Corticosteroids (early phase only)

• Prednisolone (PO) 1–2 mg/kg daily

• Duration: 5–7 days

• Most effective if started within first 24 hours

⚠ Late use may increase infection risk and delay healing.

2. Intravenous Fluids

• 0.5% Sodium Chloride

• Supplement with 20 mEq KCl

• Maintain urine output 50–80 mL/hour

3. Other therapies (Specialist Level)

• IV Immunoglobulin (IVIG)

• Cyclosporine

• Antibiotics (only if infection present)

Ophthalmologic Care

Essential to prevent:

• Corneal scarring

• Symblepharon

• Blindness

Avoid:

• Topical sulfa-containing medications

Complications

Acute

• Sepsis

• Electrolyte imbalance

• Acute kidney injury

• Respiratory failure

• Dehydration

Long-Term

• Skin scarring

• Ocular scarring → blindness

• Genital strictures

• Chronic dry eyes

• Pigmentary changes

Prevention

• Avoid re-exposure to causative drug

• Document drug allergy clearly

• Patient education on drug allergy card

• Cautious prescribing in HIV patients

• Pharmacovigilance reporting

Prognosis

• Mortality 25–40%

• Depends on:

  • Age

  • Extent of skin detachment

  • Organ involvement

  • Presence of sepsis

Early supportive care significantly improves survival.