Erythema multiforme is most commonly triggered by which infectious agent?

Erythema multiforme is most commonly triggered by which infectious agent?

• A. Streptococcus pyogenes
• B. Mycoplasma pneumoniae
• C. Varicella-zoster virus
• D. Herpes simplex virus

Answer: (D)

Erythema multiforme is an acute, immune-mediated skin reaction that often follows an infection. Among infectious triggers, herpes simplex virus—especially HSV-1—is the most common cause. The lesions are typically target-like and acral, and many cases recur, with recurrences closely linked to reactivation of latent HSV in nerve ganglia. Because antiviral suppression (for example, with acyclovir) can reduce recurrences, recognizing HSV as the leading trigger is clinically important. Other pathogens like Mycoplasma pneumoniae, Streptococcus pyogenes, or Varicella-zoster virus can trigger EM, but they are less commonly the primary cause compared to HSV.

Erythema multiforme is an acute, immune-mediated skin reaction that often follows an infection. Among infectious triggers, herpes simplex virus—especially HSV-1—is the most common cause. The lesions are typically target-like and acral, and many cases recur, with recurrences closely linked to reactivation of latent HSV in nerve ganglia. Because antiviral suppression (for example, with acyclovir) can reduce recurrences, recognizing HSV as the leading trigger is clinically important. Other pathogens like Mycoplasma pneumoniae, Streptococcus pyogenes, or Varicella-zoster virus can trigger EM, but they are less commonly the primary cause compared to HSV.