Question 10#

A 50-year-old woman develops pink macules and papules on her hands and forearms in association with a sore throat. The lesions are targetlike, with the centers a dusky violet.

What is the most likely cause of this patient’s rash?

A) Tampons and superficial skin infections
B) Drugs and herpesvirus infections
C) Rickettsial and fungal infections
D) Anxiety and emotional stress
E) Harsh soaps and drying agents

Correct Answer is B


Target lesions, especially with nonblanching violet or petechial centers, are classic manifestations of erythema multiforme. Blanchable lesions and blisters may be found as well. Common causes of erythema multiforme include drugs and herpesvirus infections (especially herpes simplex or Epstein-Barr virus). It is most important to identify the offending agent, as continuation of a causative drug can lead to oral involvement, systemic illness, and the fullblown Stevens-Johnson syndrome. The rash may take 4 to 6 weeks to resolve. Readministration of the causative agent should be scrupulously avoided. Phenytoin, sulfa drugs, barbiturates, and penicillin are common causes. The rash, with its target lesions, should not be confused with toxic shock syndrome, which causes a blanchable erythema. Rocky Mountain spotted fever causes a distal petechial rash as a result of endothelial damage. Neurodermatitis (associated with anxiety) and xerotic eczema (associated with drying agents) would not cause target lesions.