Caterpillar envenomations: a prospective study of 112 cases

A 1-year prospective study was conducted to identify epidemiological factors associated with caterpillar envenomations. Of 117 envenomations, 112 were included in the study. Identification of the caterpillars involved was accomplished in 68% of the cases. Six caterpillar species were identified, 4 of which [Hemileuca maia (Drury), Automeris io (F), Megalopyge opercularis (JE Smith)/Lagoa crispata (Packard) and Sibine stimulea (Clemens)] were properly implicated in envenomations. Clinical effects most commonly reported were local pain, erythema and swelling in 96%, 89% and 72% of patients, respectively. Atypical responses including muscle spasms, paresthesia and radiating pain to an extremity were noted in 26% of patients. Sixteen percent of patients had a history of allergy, but no patient in this subgroup exhibited a "hive-like" dermatologic or anaphylactic allergic response. No positive correlation could be drawn between allergy history and extent of clinical effect following envenomation. Mild to moderate local response following envenomation was typical. However, 61% of patients evaluated experienced mild to moderate effects at least 24 h post-envenomation.