"The caterpillar is regarded as a dangerous insect because of its venomous spines. Exposure to the caterpillar's fur-like spines leads to an immediate skin irritation characterized by a "grid-like hemorrhagic papular eruption with severe radiating pain." Victims describe the pain as similar to a broken bone or blunt-force trauma.[3] The reactions are sometimes localized to the affected area, but are often very severe, radiating up a limb and causing burning, swelling, nausea, headache, abdominal distress, rashes, blisters, and sometimes chest pain, numbness, or difficulty breathing.[6][7] Additionally, sweating from the welts or hives at the site of the sting are not unusual.
The venom from the spines is best treated within hours of first contact. For first aid, the spines (if present) should be removed by using cellophane tape.[6] Some remedies, which are reported to have varying degrees of success, include ice packs, oral antihistamine, baking soda, hydrocortisone cream, juice from the stems of comfrey plants, and calamine lotion. (or all of the above!)