Butterfly, Moth, and Caterpillar Envenomation

is an order of insects that includes butterflies, moths, and caterpillars. Several caterpillars (the larval form of butterflies and moths)found worldwide containspines or urticating hairs that secrete a toxin, irritating humans upon contact. Skin manifestations such as localized pain, edema, and erythema comprise most clinical presentations of  envenomation. However, some caterpillar species can cause severe injuries, including allergic reactions, consumptive coagulopathy, intracranial hemorrhage (ICH), acute kidney injury (AKI), ataxia, dysarthria, arthritis, joint deformities, wheezing, and dyspnea. "Lepidopterism" (derived from the Greek words  meaning scale, and  meaning wing) refers to the various skin and systemic reactions secondary to human contact with moths and butterflies. "Erucism" (derived from the Latin word , meaning caterpillar) refers to cutaneous dermatitis resulting from contact with caterpillars with urticating hairs.  More than 50 species of caterpillars are venomous in the US. The puss moth caterpillar () is considered one of the most toxic in North America and causes hundreds of human envenomations annually. Other common names include asp, tree asp, Italian asp, wooly asp, opossum bug, wooly slug, and "el perrito." The puss caterpillar is found in the southeast and south-central US (particularly Texas, Louisiana, and Florida) and is abundant during the late spring (June-July) through the early fall season (September-October). The species is often found in trees and shrubbery around homes, schools, and parks. The typical physical characteristics include a teardrop-shaped furry body with silky tan to brownish hairs. Beneath this furry coat are short hollow spines attached to a venom sac that discharges upon contact. The color of the spines ranges from white, grey, tan, or yellow to reddish-brown.   Other notable venomous caterpillars in the US include the flannel moth (), the lo moth (), the saddleback moth (a), and the hickory tiger moth ().  caterpillars in South America, especially in Brazil, are infamous for causing severe pain and hemorrhagic syndrome. In Australia, caterpillars such as the mistletoe brown-tail moth (), processionary caterpillars (), cup moths (), and the white-stemmed gum moth (i) are of medical importance. Pine processionary caterpillars () are the important defoliator of pine forests in the Mediterranean and central European countries, with significant economic and occupational consequences for workers in these forests. The  caterpillar in Nigeria is an essential protein resource but can cause thiamine deficiency syndrome similar to dry beriberi. Additionally, dendrolimus caterpillars in China and  caterpillars in Brazil are linked to significant joint disease.