Systemic allergic reaction to a caterpillar in a 3-month-old infant.

Systemic reactions to contact with a caterpillar are rare in children. A 3-month-old infant presented to the emergency department with acute onset of rash, severe respiratory distress and shock. Her mother volunteered that the infant had been exposed to a tree processionary caterpillar. The infant responded to systemic corticosteroids and antihistamines although the rash persisted for more than 5 days.