Stevens-Johnson syndrome and toxic epidermal necrolysis are two forms of the same life-threatening skin disorder that cause rash, skin peeling, and sores on the mucous membranes.
(See also Overview of Hypersensitivity and Reactive Skin Disorders.)
Stevens-Johnson syndrome and toxic epidermal necrolysis are commonly caused by medications or infections.
Typical symptoms for both disorders include peeling skin, fever, body aches, a flat red or purple rash, and blisters and sores on the mucous membranes (such as the mouth and eyes).
Affected people are typically hospitalized in a burn unit and given fluids and sometimes medications, and all suspected medications are stopped.
Skin peeling is the hallmark of these disorders. The skin peeling involves the entire top layer of the skin (the epidermis), which sometimes peels off in sheets from large areas of the body (see Structure and Function of the Skin).
Stevens-Johnson syndrome causes small areas of peeling skin (affecting less than 10% of the body).
Toxic epidermal necrolysis causes large areas of peeling skin (affecting over 30% of the body).
If 10 to 30% of body is affected, people are considered to have overlapping Stevens-Johnson syndrome/toxic epidermal necrolysis.
In both forms, blistering of the mucous membranes typically occurs in the mouth, eyes, and vagina and sometimes in the digestive, respiratory, and urinary tracts.
Both disorders can be life threatening.
Most cases of Stevens-Johnson syndrome and toxic epidermal necrolysis are caused by a reaction to a medication, most often sulfa and other antibiotics; antiseizure medications, such as phenytoin and carbamazepine; and certain other medications, such as piroxicam or allopurinol.
Some cases are caused by a bacterial infection, vaccination, or graft-versus-host disease. In children with Stevens-Johnson syndrome, an infection is the most likely cause.
Rarely, a cause cannot be identified.
These disorders occur in all age groups. They are more likely to occur in people with an abnormal immune system, such as those with a bone marrow transplant, in people with systemic lupus erythematosus, in people with other chronic joint and connective tissue diseases, or in people with human immunodeficiency virus (HIV) infection (particularly when people also have pneumonia caused by Pneumocystis jirovecii). The tendency to develop one of these disorders can run in families.
Symptoms of SJS and TEN
Stevens-Johnson syndrome and toxic epidermal necrolysis usually begin with fever, headache, cough, keratoconjunctivitis (inflammation of the conjunctiva and the cornea in the eyes), and body aches. If caused by a medication, these symptoms usually appear 1 to 3 weeks after the start of the medication. Then the skin changes begin, with a flat red or purple rash on the face, neck, and trunk, often spreading later to the rest of the body in an irregular pattern. The areas of rash enlarge and spread, often forming blisters in their center. The skin of the blisters is very loose and easy to rub off, often with just a gentle touch or pull, and the blisters peel off over a period of 1 to 3 days. The affected areas are painful, and the person feels very ill with chills and fever. In some people, eyebrows and nails fall out. The palms and soles may be affected.
In both disorders, sores appear on the mucous membranes lining the mouth, throat, anus, genitals, and eyes. The damage to the lining of the mouth makes eating difficult, and closing the mouth may be painful, so the person may drool. The eyes may become very painful and swell and become so crusted that they seal shut. The corneas can become scarred. The opening through which urine passes (urethra) may also be affected, making urination difficult and painful. Sometimes the mucous membranes of the digestive and respiratory tracts are involved, resulting in diarrhea and cough, pneumonia, and difficulty breathing.
DR M.A. ANSARY/SCIENCE PHOTO LIBRARY
The extensive skin loss in toxic epidermal necrolysis is similar to a severe burn and is equally life threatening. People are very ill and may be unable to eat or open their eyes. Huge amounts of fluids and salts can seep from the large, raw, damaged areas. People who have this disorder are very susceptible to organ failure. They are also at risk of infection at the sites of damaged, exposed tissues. Such infections are the most common cause of death in people with toxic epidermal necrolysis.
Diagnosis of SJS and TEN
A doctor's evaluation
Sometimes a skin biopsy
Doctors can usually diagnose Stevens-Johnson syndrome and toxic epidermal necrolysis by the appearance of the affected skin and mucous membranes, by their symptoms (pain rather than itching), by how quickly the skin symptoms progress, and by how much of the skin is affected.
A sample of skin may be removed and examined under a microscope (called a skin biopsy).
Treatment of SJS and TEN
Treatment in a burn center or intensive care unit
People with Stevens-Johnson syndrome or toxic epidermal necrolysis are hospitalized. Any medications suspected of causing either disorder are immediately discontinued. When possible, people are treated in a burn center or intensive care unit and given scrupulous care to avoid infection (see Severe burns). If the person survives, the skin grows back on its own, and, unlike burns, skin grafts are not needed. Fluids and salts, which are lost through the damaged skin, are replaced by vein (intravenously).
Doctors may do plasmapheresis. During this procedure, the person's blood is removed, and the plasma is separated from the blood cells and discarded. This procedure removes certain harmful substances from the blood, possibly including medications and antibodies (immune system proteins) that could be causing either disorder. After the substances are removed, the blood cells are returned to the person.
Doctors may give intravenous human immune globulin to treat toxic epidermal necrolysis. It is not clear whether this substance may help prevent further damage to skin cells.
Prognosis for SJS and TEN
In toxic epidermal necrolysis, the death rate can be as high as 25 to 35% in adults and can be even higher in older adults with very severe blistering. The death rate in children is lower.
In Stevens-Johnson syndrome, the death rate is lower than it is in toxic epidermal necrolysis.
