Stevens–Johnson Syndrome / Toxic Epidermal Necrolysis (SJS/TEN)

SJS and TEN are life-threatening, acute mucocutaneous reactions, representing a spectrum of disease triggered primarily by medications (80–90%). TEN is the most severe form, defined by >30% body surface area (BSA) detachment.

Core Problem and Triggers:

• Trigger: An idiosyncratic, drug-induced reaction.

• Typical Culprits: Anticonvulsants (e.g., lamotrigine, carbamazepine), Allopurinol, and Antibiotics (e.g., sulfonamides, minocycline).

• Timing: Onset is usually 1–3 weeks after starting the causative drug, but can be up to 8 weeks. Re-exposure causes recurrence within hours.

Prodrome (1–3 days before the rash):

Patients will describe a severe "flu-like" illness preceding the skin eruption:

• High fever, malaise, headache, and body aches.

• Sore throat, cough, and runny nose.

• Red, sore, or gritty eyes.

Rash and Mucosal Symptoms:

Rapid onset (hours to days) of a tender, painful skin eruption, starting on the trunk.

Severe pain in the mouth and lips, difficulty swallowing, crusted lips.

Sore eyes, sensitivity to light (photophobia), and genital/urinary pain.

Crucial Note for Darker Skin Tones:

The early "red rash" may be described as dark, bruise-like, or violaceous patches rather than obvious erythema. Patients may notice a burning/tenderness that is out of proportion to the visible colour change. The long-term risk of disfiguring mottled hyper- and hypopigmentation is high.

General Appearance:

The patient is typically very unwell, febrile, and in significant pain. Clinicians must assess for prognostic scores (like SCORTEN/ABCD-10) based on age, heart rate, BSA detached, and lab values.

Skin Lesions:

• • Initial Appearance: Ill-defined, dusky macules (erythematous, violaceous, or purpuric) or atypical target lesions.

  • Rapid Evolution: These lesions quickly develop flaccid blisters leading to confluent epidermal detachment (sheet-like skin loss), leaving large areas of denuded, weeping dermis.

  • Nikolsky Sign is Positive: Gentle lateral pressure causes the epidermis to shear off, confirming the subepidermal split.

  • Classification by Detachment: SJS (<10% BSA detached), Overlap (10–30%), and TEN (>30%).

Mucosal Involvement:

Present in >2 sites in most cases, indicating severe systemic disease:

• • Oral: Haemorrhagic crusts on the lips; extensive erosions/ulcers in the mouth and throat.

  • Ocular: Severe conjunctivitis, erosions, and the risk of corneal ulceration, scarring, and blindness.

  • Genital/Urinary: Painful erosions, dysuria, and long-term risk of scarring (strictures, vaginal stenosis).

Key Examination Nuances in Darker Skin Tones:

• • Early Lesions: Erythema often appears as dark red, brown, slate-grey, or violaceous discolouration. Early lesions may be subtle dusky or ashy patches; tenderness and texture change (blistering/wrinkling) are key diagnostic clues, more reliable than colour.

  • Sequelae: Monitor for striking mottled dyspigmentation (patchy hyper- and hypopigmentation) that is often more visually prominent and long-lasting. There is also a higher risk of scarring alopecia and keloidal or hypertrophic scars.

SJS/TEN is a medical emergency. Management is primarily supportive and must occur in a specialized setting (e.g., Burn Unit or ICU).

1. Immediate Steps:

• STOP THE SUSPECTED DRUG(S) IMMEDIATELY. Early cessation is the single most effective intervention for reducing mortality.

• Urgent Admission: Transfer to a facility with expertise in complex wound care, fluid management, and organ support.

2. Supportive Care (Cornerstone):

• Burn Care Principles: Gentle handling and non-adherent, sterile dressings are used (treating the skin loss like a major burn). Avoid removing blister roofs.

• Fluid and Organ Support: Fluid resuscitation, temperature control (warm environment), and pain management (often high-dose opiates) are critical.

• Infection Control: No prophylactic antibiotics; treat proven infections promptly after culture.

• Nutrition: High-calorie enteral feeding (e.g., via NG tube) is necessary due to the high metabolic demands of skin loss.

• Mucosal Care: Daily ophthalmology review and treatment (lubricants, antibiotics) to prevent eye scarring. Mouthwashes and topical anaesthetics for oral lesions.

3. Disease-Modifying Therapy (Controversial):

Evidence is mixed. Treatments are aimed at halting the immune process, ideally started within 24–72 hours.

• Ciclosporin (3–5 mg/kg/day): Some evidence suggests reduced mortality.

• IVIG (Intravenous Immunoglobulin): Used to block the apoptosis pathway; data is mixed.

• Systemic Corticosteroids: Controversial; may help if started very early but can increase the risk of infection and impair wound healing if started late.

Long-term Follow-up and Skin-of-Colour Considerations:

• Pigmentary Sequelae: Counsel patients about the likelihood of mottled hyper- and hypopigmentation persisting for months to years. Strict photoprotection is essential to minimize contrast.

• Scarring: Due to the higher risk of keloidal healing in darker skin, gentle dressing techniques and minimal debridement are crucial.

• Drug Avoidance: Ensure the patient is given a clear documentation of the culprit drug and related classes, and advised to carry a drug-alert card for life.

NCBI Bookshelf – “Stevens-Johnson Syndrome” (Oakley AM, Krishnamurthy K): https://www.ncbi.nlm.nihil.gov/books/NBK459323/

NCBI Bookshelf – “Toxic Epidermal Necrolysis” (Labib A, Milroy C): https://www.ncbi.nlm.nih.gov/books/NBK574530/

DermNet NZ – “Stevens–Johnson syndrome / toxic epidermal necrolysis”: https://dermnetnz.org/topics/stevens-johnson-syndrome-toxic-epidermal-necrolysis