Epidemic of urticaria associated with first-instar larvae of the gypsy moth (Lepidoptera: Lymantriidae)
Anderson, J.F.; Furniss, W.E.
Journal of Medical Entomology 20(2): 146-150
1983
ISSN/ISBN: 0022-2585 PMID: 6842523 Document Number: 217277
An epidemic of urticaria in early May 1981 in Connecticut USA, is attributed to gypsy moth (L. dispar) larvae. Two types of urticarial lesions lasting 2-7 days (often 4-5 days) developed primarily on exposed parts of the body. Most patients had discrete wheals 0.7-1.3 cm in diam surrounded by zones of erythema of variable size. Other patients had a more classical contact-dermatitis-like rash with linear or patchy confluence of maculopapular lesions. Persons outdoors in early May came in contact with 1st-instar larvae as they were passively deposited on their clothing and skin. Lesions developed 2-24 h after presumed contact with the caterpillars. Urticaria was diagnosed in 7.2, 10.8 and 5.1% of the children in the Newtown, Bristol and Burlington school systems, respectively. Vesicular and filamentous setae of 1st-instar larvae are attached to large glandlike cells, suggesting that 1 or both of these setae may be responsible for the urticaria.