Some people are sensitive to gypsy moth larvae and suffer skin eruptions when exposed. Reports of “gypsy moth dermatitis” are few during periods of low populations but increase during outbreaks.
The gypsy moth caterpillar is distinguished by tufts of hair on its body. Each tuft contains a combination of soft hairs and ball and socket lancets. A mature gypsy moth larva can contain 80 ng of histamine, a chemical known to trigger skin inflammation. Dinehart and colleagues found that the histamine was confined to the urticating hairs and was not present in other body parts. It is suspected that dermatitis results from the gypsy moth hairs piercing the skin and releasing histamine.