Caterpillars (long, fuzzy, segmented insects) are unable to pierce the skin with their bite. However, their hairs may get into the skin or eyes, causing symptoms in the area where the hairs entered.
Problems also can occur if someone breathes in caterpillar hairs that have been released into the air, or eats caterpillars.
This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call your local emergency number (such as 911) or the National Poison Control Center at 1-800-222-1222.
Mouth and throat irritation
Vomiting, if caterpillar or caterpillar hairs are eaten
Remove irritating caterpillar hairs. If the caterpillar was on the skin, apply adhesive tape (such as duct or masking tape) to the site, then pull it off. Repeat as needed until all hairs are removed. Apply calamine lotion to the affected area, and then ice. Place ice (wrapped in a washcloth or other suitable covering) on the affected area for 10 minutes and then off for 10 minutes. Repeat this process. If patient has circulatory problems, decrease the time to prevent possible damage to the skin.
If the caterpillar touched the eyes, flush the eyes immediately with plenty of water and then get medical help.
Get medical care if you breathe in caterpillar hairs.
Before Calling Emergency
Determine the following information:
Patient's age, weight, and condition
Type of caterpillar, if possible
Time of the incident
The National Poison Control Center (1-800-222-1222) can be called from anywhere in the United States. This national hotline number will let you talk to experts in poisoning. They will give you further instructions.
This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.
The health care provider will measure and monitor your vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated as appropriate. You may receive:
Blood and urine tests
Eye examination and topical numbing (anesthetic) drops
Eye flushing with water or saline
Medications to control pain, itching and allergic reactions
Skin examination to remove all caterpillar hairs
In more serious reactions, x-rays and EKG (electrocardiogram, or heart tracing) may be necessary.
The faster you get medical help, the better the chance for recovery. The outcome is usually very good.
Wear protective clothing whenever possible when traveling through terrain which is known to harbor caterpillars. Do not stick your hands or feet in their nests or in their preferred habitats, namely, under logs or underbrush, or other damp, moist areas.
Steen CJ, Schwartz RA. Arthropod bites and stings. In: Wolff K, Goldsmith LA, Katz SI, et al., eds. Fitzpatrick's Dermatology in General Medicine. 7th ed. New York, NY: McGraw-Hill; 2008:chap 210.
Erickson, TB, Márquez A, Jr. Arthropod envenomation and parasitism. In: Auerbach PS, ed. Wilderness Medicine. 6th ed. Philadelphia, Pa: Mosby Elsevier; 2011:chap 50.
Jacob L. Heller, MD, MHA, Emergency Medicine, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, and the A.D.A.M. Editorial team.