Most EM cases in children are precipitated by herpes simplex virus infection, though the infection may no longer be apparent by the time EM develops. Mycoplasma pneumoniaeand other infectious organisms may also trigger EM. Symptomatic treatment is usually sufficient. Oral antihistamines help suppress pruritus, stinging, and burning. The use of systemic corticosteroids is controversial but may be considered for severe mucosal disease. Antiviral medications targeting herpes simplex virus do not alter the course of the EM, though children with recurrent EM may be candidates for prophylactic antivirals. The prognosis is excellent, with most lesions lasting no more than 2 weeks. Healing occurs without scarring.
SJS, TEN, and SJS/TEN overlap are severe, life-threatening disorders thought to represent the same disease continuum. Theyare usually preceded by a prodrome of fever, malaise, and upperrespiratory symptoms 1 to 14 days before the onset of cutaneouslesions. Red macules appear suddenly and tend to coalesce intolarge patches, with a predominant distribution over the face andtrunk. Atypical targets may be present, causing diagnostic confusion initially with EM, although the atypical targets lack thecharacteristic three zones. Skin lesions evolve rapidly into bullaeand areas of necrosis. SJS is defined as epidermal detachment ofless than 10% of the body surface area, whereas SJS/TEN overlap has 10% to 30% and TEN has greater than 30% body surface area involvement. Any mucosal surface may be involved.The upper and lower lips are generally swollen and bright redwith erosions and hemorrhagic crusts, and the remainder of theoral mucosa may also be involved. Early in the disease process,there is bilateral conjunctival injection; however, this usuallyprogresses to conjunctival erosions. There may be erosions ofthe penile, vaginal, or perianal mucosa. Urogenital, esophageal,and tracheal surfaces may be involved in the most severe cases.
Drugs and Mycoplasma pneumoniae infections are the most common causes of SJS/TEN in children. The most common drugs implicated are nonsteroidal anti-inflammatory drugs, sulfonamides, anticonvulsants, and antibiotics. Other precipitating factors are viral infections, bacterial infections, syphilis, and deep fungal infections.
SJS/TEN can occur at any age. The diagnosis of SJS/TEN is clinical; there are no diagnostic tests. Confusion with EM, Kawasaki disease, and bacterial toxin-mediated diseases (scarlet fever, toxic shock syndrome, and staphylococcal scalded skin syndrome) may occur. Patients with Kawasaki disease have conjunctival injection and hyperemia of the mucous membranes. Necrosis of the mucosal surfaces does not occur; blistering, erosions, and severe crusting are not observed. The mucosal changes of staphylococcal scalded skin syndrome are minor, and frank erosions are not present. The blistering of the skin is more superficial and favors intertriginous regions.
SJS/TEN is a serious illness with a mortality rate as high as35% for severe cases of TEN. Prompt discontinuation of theoffending agent is key. No controlled clinical trials regardingmedical therapy exist, though early initiation of intravenous immunoglobulin has been proposed. Supportive care is anotheressential component of therapy, and a multidisciplinary careteam is often necessary. Sepsis is the major cause of morbidityand mortality, so meticulous wound care is crucial, with stringent surveillance for cutaneous infections and use of antibiotics as warranted. Parenteral or nasogastric feeding should beinstituted early to accelerate the healing process. Careful fluidmanagement and monitoring of electrolytes are critical. Ocular complications are a major cause of long-term morbidity, soearly involvement of an ophthalmologist is important.