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Author: Vanessa Ngan, Staff Writer; Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, 2003. Updated by Dr Delwyn Dyall-Smith, 2009. Further updated by Dr Amanda Oakley, January 2016.
Stevens–Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are now believed to be variants of the same condition, distinct from erythema multiforme. SJS/TEN is a very rare, acute, serious, and potentially fatal skin reaction in which there is sheet-like skin and mucosal loss. Using current definitions, it is nearly always caused by medications.
SJS/TEN is a very rare complication of medication use (estimated at 1–2/million each year for SJS, and 0.4–1.2/million each year for TEN).
Genetic factors are important.
More than 200 medications have been reported in association with SJS/TEN.
The drugs that most commonly cause SJS/TEN are:
SJS/TEN is a rare and unpredictable reaction to medication. The mechanism has still not been understood and is complex.
Drug specific CD8+ cytotoxic lymphocytes can be detected in the early blister fluid. They have some natural killer cell activity and can probably kill keratinocytes by direct contact. Cytokines implicated include perforin/granzyme, Fas-L and tumour necrosis factor alpha (TNFα).
There are probably two major pathways involved:
SJS/TEN usually develops within the first week of antibiotic therapy but up to 2 months after starting an anticonvulsant. For most drugs the onset is within a few days up to 1 month.
Before the rash appears, there is usually a prodromal illness of several days duration resembling an upper respiratory tract infection or 'flu-like illness. Symptoms may include:
There is then an abrupt onset of a tender/painful red skin rash starting on the trunk and extending rapidly over hours to days onto the face and limbs (but rarely affecting scalp, palms or soles). The maximum extent is usually reached by 4 days.
The skin lesions may be:
The blisters then merge to form sheets of skin detachment, exposing red, oozing dermis. The Nikolsky sign is positive in areas of skin redness. This means that blisters and erosions appear when the skin is rubbed gently.
Mucosal involvement is prominent and severe, although not forming actual blisters. At least 2 mucosal surfaces are affected including:
The patient is very ill, extremely anxious and in considerable pain. In addition to skin/mucosal involvement, other organs may be affected including liver, kidneys, lungs, bone marrow and joints.
SJS/TEN can be fatal due to complications in the acute phase. The mortality rate is up to 10% for SJS and at least 30% for TEN.
During the acute phase, potentially fatal complications include:
SJS/TEN is suspected clinically and classified based on the skin surface area detached at maximum extent.
|TEN with spots||
|TEN without spots||
The category cannot always be defined with certainty on initial presentation. The diagnosis may therefore change during the first few days in hospital.
If the test is available, elevated levels of serum granulysin taken in the first few days of a drug eruption may be predictive of SJS/TEN.
The histopathology shows keratinocyte necrosis (death of individual skin cells), full thickness epidermal/epithelial necrosis (death of an entire layer of skin), minimal inflammation (very mild lymphocytic infiltrate of the superficial dermis). The direct immunofluoresence test on the skin biopsy is negative, indicating the disease is not due to deposition of antibodies in the skin.
Blood tests do not help to make the diagnosis but are essential to make sure fluid and vital nutrients have been replaced, to identify complications and to assess prognostic factors (see below). Abnormalities may include:
Patch testing rarely identifies the culprit in SJS/TEN following recovery, and is not recommended.
SCORTEN is an illness severity score that has been developed to predict mortality in SJS and TEN cases. One point is scored for each of seven criteria present at the time of admission. The SCORTEN criteria are:
The risk of dying from SJS/TEN depends on the score.
|SCORTEN 5 or more||>90%|
In the differential diagnosis of SJS/TEN consider:
Care of a patient with SJS/TEN requires:
The role of systemic corticosteroids (cortisone) remains controversial. Some clinicians prescribe high doses of corticosteroids for a short time at the start of the reaction, eg prednisone 1–2 mg/kg/day for 3–5 days. However concerns have been raised that they may increase the risk of infection, impair wound healing and other complications, and they have not been proven to have any benefit. They are not effective later in the course of the illness.
Thalidomide, trialled because of its anti-TNFα effect, increased mortality, and should not be used.
People who have survived SJS/TEN must be educated to avoid taking the causative drug or structurally related medicines as SJS/TEN may recur. Cross-reactions can occur between:
In the future, we may be able to predict who is at risk of SJS/TEN using genetic screening.
Allopurinol should be prescribed for good indications (eg, gout with hyperuricaemia) and commenced at low dose (100 mg/day), as SJS/TEN is more likely at doses >200 mg/day.
The acute phase of SJS/TEN lasts 8–12 days.
Repithelialisation of denuded areas takes several weeks, and is accompanied by peeling of the less severely affected skin. Survivors of the acute phase have increased on-going mortality especially if aged or sick.
Long-term sequelae include:
Eye problems can lead to blindness:
It may take weeks to months for symptoms and signs to settle.
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