The venomous puss moth caterpillar (also called the asp) is present in the southern United States. It is teardrop shaped and has long silky hair, making it resemble a tuft of cotton or fur. When a puss moth caterpillar rubs or is pressed against a person's skin, its venomous hairs are embedded, usually causing severe burning and a rash. Pain usually subsides in about an hour. Occasionally, the reaction is more severe, causing swelling, nausea, and difficulty breathing.

People have gotten relief from puss moth caterpillar stings by putting tape on the site and pulling it off to remove embedded hairs. Use of a baking soda slurry or calamine lotion can be soothing, and an ice pack can ease pain. More severe reactions require immediate medical attention.

Last full review/revision February 2009 by Robert A. Barish, MD, MBA