Derm diagnoses you can’t afford to miss

SJS: Triggered by drugs, and infections, too

Stevens-Johnson syndrome (SJS), also known as erythema multiforme major, is an often-debilitating and possibly fatal adverse reaction, typically (but not exclusively) to a drug. It manifests as full-thickness epidermal necrosis of the mucous membranes.^30,31 SJS occurs at a rate of about 1 to 7 cases per million people per year, and has a mortality rate of approximately 5%.^30-32 The types of medication that most commonly precipitate SJS are anticonvulsants, sulfa drugs, penicillin-related and cephalosporin antibiotics, anti-inflammatory agents, and certain neoplastic drugs.^30,32 SJS can develop in response to infections and neoplasms (TABLE) as well, and in many cases a cause is never found.

Patients with widespread involvement often complain of a burning sensation, particularly around the mouth.^32-36 In some cases, this is the presenting sign, because the oral mucosa tends to be among the first mucous membranes involved.

TABLE
Stevens-Johnson syndrome: Pinpointing the cause³²

Targetoid lesions, Nikolsky sign are diagnostic clues

The characteristic skin lesions seen with SJS consist of initially erythematous macules that rapidly develop central necrosis to form vesiculation, as well as other variable areas of denudation (FIGURE 3). These vesicles tend to demonstrate confluence and often show a positive Nikolsky sign—epidermal detachment of superficial layers of the skin when slight pressure is applied. The lesions typically take on a targetoid appearance. If left untreated, the blisters often result in ulceration and hemorrhagic crusting of affected areas.

Like most skin disorders, SJS is initially diagnosed on the basis of clinical presentation. However, it is a rare disorder, and commonly misdiagnosed. Among the disorders SJS has been mistaken for are staphylococcal scalded skin syndrome, toxic shock syndrome, exfoliative dermatitis, scarlet fever, erythema multiforme, and iatrogenic chemical burns.^32,37 (Erythema multiforme, SJS, and toxic epidermal necrolysis [TEN] are considered part of the same disease spectrum; erythema multiforme typically presents with few random lesions and no mucosal involvement, SJS with mucosal involvement on up to 30% of the body surface, and TEN with >30%.)^32,37 Skin biopsies and immunofluorescence studies are recommended to confirm the diagnosis.

During the course of SJS, the mucous membranes of the oropharynx, ocular cavity, gastrointestinal system, nasal cavity, genitourinary system, and lower respiratory tracts are typically affected.^32-35 As the condition progresses, increased epidermal erosion can lead to the sloughing off of up to 100% of the epidermis, resulting in considerable fluid loss.^32,34

Corneal ulceration, anterior uveitis, panophthalmitis, polyarthritis, hematuria, and acute tubular necrosis leading to renal failure may also occur.^32,35,37 Scarring within vital ocular structures can result in corneal opacity and lead to significant visual impairment. In severe cases, blood loss and fluid loss increase the risk of bacterial superinfection and sepsis.^35,37

FIGURE 3
Targetoid lesions are characteristic of SJS

Supportive therapy, wound care are key components of treatment

Rapid cessation of the offending agent with targeted dermatologic management can reduce morbidity by promoting rapid re-epithelialization of affected skin. (See “SJS is diagnosed, but not quickly,” [Verdicts] on page 332, for a discussion of the dangers of delayed diagnosis and failure to promptly stop the drug causing the acute reaction.)

Closely monitoring the patient for fluid and electrolyte abnormalities is also crucial. Corticosteroids and IV immunoglobulins have been suggested for early severe cases of SJS, but their efficacy in treating this condition has yet to be established by prospective double-blind studies.^32-37

The skin lesions associated with SJS should be treated in the same way you would treat thermal burns, with local wound care, warm compresses, and topical anesthetics for pain reduction.^36,37 Oral lesions are managed with diphenhydramine or sodium bicarbonate mouthwashes and glycerin swabs.

An ophthalmologic consultation is mandatory because of the risk of vision loss associated with corneal scarring.