ABSTRACT
Most beetles are harmless and can be handled by humans with no ill effects; however, blister beetles, primarily species in the families Meloidae, Oedemeridae, and Staphylinidae, possess vesicating chemical substances in their body fluids. The blistering fluid in meloids and oedemerids is cantharidin but is a somewhat different compound in staphylinids. Blisters resulting from blister beetle exposure are generally not serious, and reabsorption usually occurs in a few days if the blisters are unruptured. For treatment, exposed areas should be washed, antibiotic ointments applied to prevent secondary infection, and the areas bandaged for protection until the blisters reabsorb. Caterpillars of many species can produce mild to severe dermatitis, urticaria, nodular conjunctivitis, pain, headache, and even convulsions (rare) via tiny hairs that irritate or inject a venom. Both mechanical irritation and injection of venom by the caterpillar spines or hairs contribute to the urticarial response in humans.
