Gypsy moth-induced dermatitis: a hospital review and community survey

Lymantria dispar (gypsy moth [GM]) is found in most temperate forests. Although GM caterpillars are known to cause outbreaks of dermatitis, there have been few clinical/epidemiological studies of this problem. Here, we investigated GM caterpillar-induced health problems in a heavily infested area. We reviewed the records of 229 GM caterpillar-induced dermatitis patients treated at Kuzumaki Hospital and conducted a questionnaire survey covering all 2,891 households (7,770 residents) in Kuzumaki town. Affected areas were located primarily on the neck and arms. 180 patients (79%) did not notice direct contact with GM caterpillars on their affected areas. There were no significant differences in demographics, history, and symptoms between the group of patients with direct contact and those without direct contact. In the questionnaire survey, of the 4,871 people who responded (63%), 2039 people (42%) reported having dermatitis. When the data were adjusted for age, gender was not associated with dermatitis; however, the age groups 70-79 years and ≥80 years showed lower incidences of dermatitis. Those experiencing similar dermatitis the previous year had a significantly higher occurrence of dermatitis: odds ratio (OR)=42.4, 95% confidence interval (CI): 33.5-53.6. Thus, when GM infestation occurs, physicians should expect an outbreak of dermatitis.