British Columbia Drug and Poison Information Centre (BC DPIC)

Caterpillars are the larvae of moths and butterflies. Many caterpillars are hairy, but few are harmful. In Canada, common stinging caterpillars include larvae of the tiger, tussock, tent and gypsy moths. Worldwide there are other types that can cause toxic or allergic reactions.

Are they toxic? (includes caterpillars in Canada only):  The stinging caterpillar has hairs or spines capable of penetrating the skin and causing a local reaction. Exposure can occur through direct contact with a live or dead caterpillar or from indirect contact (with loose hairs present in cocoons or carried on clothing or pets). Caterpillar hairs that are embedded or stuck in the eye, skin and mouth may be difficult to see, and may require a magnifying glass to visualize.

Health Effects:
Eye: The hairs may become embedded in the eye. Discomfort, redness, and swelling are common. Potential injury to the cornea and deeper chambers of the eye.

Skin: May cause an immediate prickly sensation or discomfort. Area may become red, swollen and have small raised bumps or blisters.

Ingestion: The hairs may become embedded in the tongue or mouth causing irritation, swelling, difficulty swallowing and drooling. Swelling in the mouth may result in breathing difficulties. If swallowed, an upset stomach and diarrhea may develop.

What to do?
Eye: Rinse eyes with a gentle stream of lukewarm water for 5 minutes by any of the following methods:

• Pour a gentle stream of water from a jug or clean teapot over the eye from the inside corner by the nose, across the eye, flowing out towards the ear.
• Submerge eye in a container (bowl, sink) of lukewarm water. Have patient open and close eye.
• Eye may be irrigated in the shower, if this can be accomplished without delay.
• Young children may be wrapped like a mummy in a towel with arms at side and held over the sink or tub or laid on counter during flushing.
• All eye exposures require assessment in the Emergency Department due to the potential for ocular injury. If you have any questions or concerns contact the Poison Control Centre.

• Wash the area thoroughly with soap and water.
• Do not touch the eyes until any hairs have been removed from the skin.
• Use a magnifying glass, look at the skin for any embedded hairs.
• To remove hairs, apply adhesive tape and then peel the tape off. The hairs usually come off with the tape.
• Rub an aluminum-containing antiperspirant on area to relieve symptoms of irritation and discomfort.
• Contact the Poison Control Centre for further information.

• Rinse out the mouth and have a glass of water or milk.
• Suck on a popsicle or have some ice cream to help relieve any discomfort.
• If there is swelling of the mouth or tongue and difficulty breathing develops call an ambulance immediately. Otherwise, contact the Poison Control Centre.

How can I prevent exposure? Do not touch or handle caterpillars.

Need more information: Call the Poison Control Centre.