Master the board step 3

Dermatology
Erythema Multiforme (EM)
Erythema multiforme is caused by the following:
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Penicillins
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Phenytoin
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NSAIDs
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Sulfa drugs
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Infection with herpes simplex or mycoplasma
This condition presents with targetlike lesions that especially occur on the
palms and soles. These lesions can also be described as “irislike.” Bullae are
not uniformly found. EM of this type usually does not involve mucous membranes.
Treatment is with antihistamines and treatment of the underlying infection.
Stevens-Johnson Syndrome (SJS)
It is sometimes difficult to distinguish SJS from toxic epidermal necrolysis
(TEN), and, in fact, the 2 diseases may be considered as being on a spectrum
of severity of the same disorder.
Disorders along this spectrum may arise as a hypersensitivity response
to the same set of medications, such as penicillins, sulfa drugs, NSAIDs,
phenytoin, and phenobarbital. SJS usually involves < 10–15 percent of the
total body surface area, and the overall mortality is < 5–10 percent. There is
mucous membrane involvement, most often of the oral cavity and the conjunctivae,
although there may be extensive involvement of the respiratory tract.
Respiratory tract involvement may be so severe as to require mechanical
ventilation. These patients should be managed in a burn unit. Death occurs
from a combination of infection, dehydration, and malnutrition.
Steroids have no proven benefit. Therapies of possible value are intravenous
immunoglobulins, cyclophosphamide, cyclosporine, and thalidomide.
Toxic Epidermal Necrolysis (TEN)
TEN is the most serious version of cutaneous hypersensitivity reaction.
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Much more of the body surface area (BSA) is involved, up to 30–100 percent.
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Mortality may be as high as 40–50 percent.
Nikolsky’s sign is present, and the skin easily sloughs off. TEN has certain
similar features to staphylococcal scalded skin syndrome. However, TEN is
drug induced as opposed to being caused by a toxin coming from an organism.
Sepsis is the most common cause of death, but prophylactic systemic antibiotics
are not indicated.
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