Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are clinically similar except for their distribution. By one commonly accepted definition, changes affect < 10% of body surface area in SJS and > 30% of body surface area in TEN; involvement of 10 to 30% of body surface area is considered SJS/TEN overlap.
The disorders affect between 1 and 5 people/million. Incidence, severity, or both of these disorders may be higher in bone marrow transplant recipients, in Pneumocystis jirovecii–infected HIV patients, in patients with systemic lupus erythematosus, and in patients with other chronic rheumatologic diseases.
Etiology of SJS and TEN
Drugs precipitate over 50% of SJS cases and up to 95% of TEN cases. The most common drug causes include
Cases that are not caused by drugs are attributed to
Infection (mostly with Mycoplasma pneumoniae)
Vaccination
Rarely, a cause cannot be identified.
Pathophysiology of SJS and TEN
The exact mechanism of Stevens-Johnson syndrome and toxic epidermal necrolysis is unknown; however, one theory holds that altered drug metabolism (eg, failure to clear reactive metabolites) in some patients triggers a T-cell–mediated cytotoxic reaction to drug antigens in keratinocytes. CD8+ T cells have been identified as important mediators of blister formation.
Findings suggest that granulysin released from cytotoxic T cells and natural killer cells might play a role in keratinocyte death; granulysin concentration in blister fluid correlates with severity of disease. Interleukin-15 has also been found to be increased in patients with SJS/TEN and has been found to increase granulysin production. Another theory is that interactions between Fas (a cell-surface receptor that induces apoptosis) and its ligand, particularly a soluble form of Fas ligand released from mononuclear cells, lead to cell death and blister formation. A genetic predisposition for SJS/TEN has been suggested.
Symptoms and Signs of SJS and TEN
Within 1 to 3 weeks after the start of the offending drug, patients develop a prodrome of malaise, fever, headache, cough, and keratoconjunctivitis. Macules, often in a target configuration, then appear suddenly, usually on the face, neck, and upper trunk. These macules simultaneously appear elsewhere on the body, coalesce into large flaccid bullae, and slough over a period of 1 to 3 days. Nails and eyebrows may be lost along with epithelium. The palms and soles may be involved. Skin, mucosal, and eye pain are common. In some cases, diffuse erythema is the first skin abnormality of toxic epidermal necrolysis.
In severe cases of toxic epidermal necrolysis, large sheets of epithelium slide off the entire body at pressure points (Nikolsky sign), exposing weepy, painful, and erythematous skin. Painful oral crusts and erosions, keratoconjunctivitis, and genital problems (eg, urethritis, phimosis, vaginal synechiae) accompany skin sloughing in up to 90% of cases. Bronchial epithelium may also slough, causing cough, dyspnea, pneumonia, pulmonary edema, and hypoxemia. Glomerulonephritis and hepatitis may develop.
Diagnosis of SJS and TEN
Clinical evaluation
Often skin biopsy
Diagnosis is often obvious from appearance of lesions and rapid progression of symptoms. Histologic examination of sloughed skin shows necrotic epithelium, a distinguishing feature.
Differential diagnosis in Stevens-Johnson syndrome (SJS) and early toxic epidermal necrolysis (TEN) includes erythema multiforme, viral exanthems, and other drug rashes; SJS/TEN can usually be differentiated clinically as the disorder evolves and is characterized by significant pain and skin sloughing. In later stages of TEN, differential diagnosis includes the following:
Toxic shock syndrome (usually has more prominent multiple organ involvement and different cutaneous manifestations, such as macular rash on palms and soles that evolves to desquamation over about 2 weeks)
Exfoliative erythroderma (usually spares mucous membranes and is not as painful)
Paraneoplastic pemphigus (sometimes with different mucocutaneous findings or in patients with evidence of cancer)
In children, TEN is less common and must be distinguished from staphylococcal scalded skin syndrome. Characteristics of staphylococcal scalded skin syndrome usually include sparing of mucous membranes, absence of risk factors for TEN (eg, drug history), and clinical suspicion of staphylococcal infection.
Prognosis for SJS and TEN
Severe toxic epidermal necrolysis is similar to extensive burns; patients are acutely ill, may be unable to eat or open their eyes, and suffer massive fluid and electrolyte losses. They are at high risk of infection, multiorgan failure, and death. With early therapy, survival rates approach 90%. The severity-of-illness score for toxic epidermal necrolysis systematically scores 7 independent risk factors within the first 24 hours of presentation to the hospital to determine the mortality rate for a particular patient.
Severity-of-Illness Score for Toxic Epidermal Necrolysis (SCORTEN)
Risk Factor* | Score | |
|---|---|---|
0 | 1 | |
Age | < 40 years | ≥ 40 years |
Associated cancer | No | Yes |
Heart rate (beats/minute) | < 120 | ≥ 120 |
≤ 28 mg/dL (10 mmol/L) | > 28 mg/dL (10 mmol/L) | |
Detached or compromised body surface | < 10% | ≥ 10% |
Serum bicarbonate | ≥ 20 mEq/L (≥ 20 mmol/L) | < 20 mEq/L (< 20 mmol/L) |
Serum glucose | ≤ 250 mg/dL (≤ 13.88 mmol/L) | > 250 mg/dL (> 13.88 mmol/L) |
* More risk factors indicate a higher score and a higher mortality rate (%) as follows:
| ||
CI = confidence interval. | ||
Data from Bastuji-Garin S, Fouchard N, Bertocchi M, et al: SCORTEN: A severity-of-illness score for toxic epidermal necrolysis. J Invest Dermatol 115:149–153, 2000. doi: 10.1046/j.1523-1747.2000.00061.x | ||
Treatment of SJS and TEN
Supportive care
Possibly corticosteroids, plasmapheresis, IV immune globulin (IVIG), or tumor necrosis factor (TNF)-alpha inhibitors
Treatment is most successful when Stevens-Johnson syndrome and toxic epidermal necrolysis are recognized early and treated in an inpatient dermatologic or intensive care unit setting; treatment in a burn unit may be needed for severe disease. Ophthalmology consultation and specialized eye care are mandatory for patients with ocular involvement. Potentially causative drugs should be stopped immediately. Patients are isolated to minimize exposure to infection and are given fluids, electrolytes, blood products, and nutritional supplements as needed. Skin care includes prompt treatment of secondary bacterial infections and daily wound care as for severe burns. Prophylactic systemic antibiotics are controversial and often avoided.
Plasmapheresis can remove reactive drug metabolites or antibodies and can be considered. Early high-dose IVIG 2.7 g/kg over 3 days blocks antibodies and Fas ligand. However, despite some remarkable initial results using high-dose IVIG for toxic epidermal necrolysis, further clinical trials involving small cohorts have reported conflicting results, and a retrospective analysis has suggested no improvement or even higher than expected mortality (1).
Treatment reference
1. Kirchhof MG, Miliszewski MA, Sikora S, et al:J Am Acad Dermatol 71(5):941–947, 2014. doi: 10.1016/j.jaad.2014.07.016
Key Points
Drugs cause > 50% of Stevens-Johnson syndrome (SJS) and up to 95% of toxic epidermal necrolysis (TEN) cases, but infection, vaccination, and graft-vs-host disease are also potential causes.
Confirm the diagnosis by biopsy (showing necrotic epithelium) if clinical characteristics (eg, target lesions progressing to bullae, ocular and mucous membrane involvement, Nikolsky sign, desquamation in sheets) are inconclusive.
Early treatment decreases the often high mortality rate.
Except for mild cases, treat SJS/TEN in a burn unit and with intensive supportive care.
Consult ophthalmology if the eyes are affected.
