Accidents caused by urticating or poisonous setae from lepidoptera caterpillars are known as erucism. These accidents are produced by accidental contact, especially in children, with bristles on the insect’s body surface, connected to venom glands. Symptoms may be local or systemic, with deadly clinical presentations. The accident caused by Lonomia spp. caterpillars can trigger bleeding disorders, which is considered the most severe type of erucism. The case of a 5-year-old girl is reported. She was from the town of Villarondos, in the Peruvian Amazon, department of Huánuco, who accidentally knelt down on caterpillar bristles, and subsequently experienced hemolytic anemia, plateletopenia, and coagulation disorder. The diagnosis was made based on the medical history, clinical manifestation, laboratory examination results, and response to antilonomic serum. The clinical, laboratory, and therapeutic aspects of erucism due to Lonomia spp. are discussed.