Stevens–Johnson syndrome and toxic epidermal necrolysis !

A rare, life-threatening drug reaction in which the skin and the lining of the mouth, eyes and genitals blister and peel off, much like a severe burn.

Updated 2026-11-01

Structures involved

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Why it happens

What it is

Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are one spectrum of severe mucocutaneous reaction, almost always to a drug, in which the epidermis dies and detaches. They are graded by the share of body surface that detaches.

Who gets it

Rare worldwide, with a few cases per million people per year; SJS is more frequent than TEN. Risk is higher in people living with HIV and in some genetic backgrounds. In Latin America, as elsewhere, anticonvulsants, allopurinol, sulfonamide antibiotics and nevirapine are the classic triggers.

Causes

Drugs in most cases, usually started 4 days to 8 weeks before onset
Anticonvulsants (carbamazepine, phenytoin, lamotrigine, phenobarbital)
Allopurinol and sulfonamide antibiotics such as trimethoprim-sulfamethoxazole
Nevirapine and oxicam-type NSAIDs
Infections, especially Mycoplasma pneumoniae in children

Risk factors

HIV infection
Systemic lupus erythematosus and other immune disorders
Certain HLA-B alleles (e.g. HLA-B*15:02 with carbamazepine, HLA-B*58:01 with allopurinol)
Older age, cancer and kidney failure (slower drug clearance)
A previous episode with the same or a related drug

Pathophysiology

The drug, often presented on specific HLA molecules, activates cytotoxic T cells and natural killer cells. They release granulysin, Fas ligand and perforin-granzyme, which trigger widespread keratinocyte death. The full-thickness epidermis separates from the dermis, so the skin loses its barrier against fluid loss, heat loss and infection, as in a large burn.

Classification

SJS: detachment of less than 10% of body surface area
SJS–TEN overlap: 10–30%
TEN: more than 30%

Symptoms and signs

Fever, sore throat, burning eyes and malaise 1–3 days before the rash
Painful dusky red or purplish macules and atypical target lesions, starting on the face and trunk
Flaccid blisters and sheets of skin that peel off, leaving raw red areas
Positive Nikolsky sign: the skin slides off with gentle lateral pressure
Erosions of the lips, mouth, eyes and genitals in nearly all cases

Diagnosis

Clinical: Recognition of the rash, mucosal erosions and Nikolsky sign, a careful drug history with start dates, and an estimate of the detached body surface. SCORTEN, scored in the first days, predicts mortality from age, heart rate, cancer, detached surface, serum urea, bicarbonate and glucose.
Tests: Skin biopsy shows full-thickness epidermal necrosis with little inflammation; direct immunofluorescence helps exclude autoimmune blistering disease. Blood count, electrolytes, kidney and liver function, glucose, bicarbonate and cultures; Mycoplasma testing in children.
Imaging: Not needed for diagnosis; chest X-ray when respiratory involvement or infection is suspected.

Differential diagnosis

Erythema multiforme major (typical targets, mostly on the limbs, often after herpes simplex)
Staphylococcal scalded skin syndrome (superficial split, mucosa spared, mainly young children)
Drug reaction with eosinophilia and systemic symptoms (DRESS)
Autoimmune blistering diseases such as pemphigus vulgaris
Generalised bullous fixed drug eruption

Goal of treatment

Stop the culprit drug at once, support the skin and body as in a major burn, protect the eyes and mucosa, and prevent infection and long-term damage.

Treatment

Acute: Immediate withdrawal of every suspected drug; this is the single most important measure.
Acute: Admission to a burn or intensive care unit: warm room, careful fluid and electrolyte replacement, nutrition, pain control and non-adherent dressings, avoiding unnecessary skin trauma.
Medical: Immunomodulating drugs such as ciclosporin, TNF inhibitors (etanercept), intravenous immunoglobulin or systemic corticosteroids are used in some centres; evidence is still debated.
Follow-up: Daily ophthalmology review, mouth and genital care, close watch for sepsis, fluid balance, temperature and airway; nurses use strict asepsis and gentle handling of the skin.
Rehabilitation: After recovery: eye follow-up, skin care and documented lifelong avoidance of the drug and related compounds (allergy alert band and record).

Complications

Sepsis, the main cause of death
Fluid, electrolyte and heat loss with hypovolaemia and acute kidney injury
Ocular scarring, dry eye, symblepharon and blindness
Respiratory involvement and pneumonia
Skin pigment changes, nail loss and genital or oral strictures

Prognosis

Mortality is roughly 10% in SJS and up to about 30–50% in TEN, rising with SCORTEN. Survivors re-epithelialise in 2–3 weeks but often keep long-term eye problems; re-exposure to the drug can cause a faster and more severe relapse.

Prevention

HLA-B*15:02 screening before carbamazepine in people of at-risk ancestry and HLA-B*58:01 before allopurinol where recommended
Using high-risk drugs only when clearly indicated and teaching patients to report fever, rash or mouth sores early
Recording the culprit drug clearly in the medical record

Test yourself

Think of the answer, then tap the question to see it.

What body surface area thresholds separate SJS, overlap and TEN?

SJS under 10% detachment, SJS–TEN overlap 10–30%, and TEN more than 30% of body surface area.

What is the most important first step in managing SJS/TEN?

Immediate withdrawal of the suspected drug, followed by burn-unit or ICU supportive care.

What are three classic drug triggers of SJS/TEN?

Anticonvulsants (carbamazepine, phenytoin, lamotrigine), allopurinol and sulfonamide antibiotics; nevirapine is another.

Which score predicts mortality in TEN?

SCORTEN, based on age, cancer, heart rate, detached surface, urea, bicarbonate and glucose.

What is the main cause of death in SJS/TEN?

Sepsis, because the denuded skin loses its barrier against infection.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: Stevens-Johnson syndrome/toxic epidermal necrolysis (MedlinePlus (U.S. National Library of Medicine), 2024).

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Representative model, for educational purposes only.

Skin highlighted on the Durgical 3D model