The venomous puss moth caterpillar (Megalopyge opercularis; 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.
(See also Introduction to Bites and Stings.)
Several techniques may soothe the pain and burning caused by puss moth caterpillar stings.
Washing the sting with soap and water and using a hair dryer set on low to dry the area
Putting tape on the site and pulling it off to remove embedded hairs to prevent further injury
Applying isopropyl alcohol (rubbing alcohol) to the sting
Applying a baking soda slurry
Applying calamine lotion
Placing an ice pack or an ice cube wrapped in plastic and a thin cloth over the sting
More severe reactions require immediate medical attention.