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Puss Moth Caterpillar Stings

by Robert A. Barish, MD, MBA, Thomas Arnold, MD

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.

Washing the sting with soap and water and using a hair dryer set on low to dry the area may soothe the burning. People have also gotten relief from puss moth caterpillar stings by putting tape on the site and pulling it off to remove embedded hairs. Applying isopropyl alcohol (rubbing alcohol) to the sting may also help relieve the burning. Use of a baking soda slurry or calamine lotion can be soothing, and an ice pack or an ice cube wrapped in plastic and a thin cloth and placed over the sting can ease pain. More severe reactions require immediate medical attention.