Take Precautions Against Browntail Moth Hairs When Outside

May 2, 2022

AUGUSTA – The Maine Center for Disease Control and Prevention (Maine CDC), Maine Forest Service (MFS), and 211 Maine remind Maine residents and visitors to watch out for browntail moth caterpillars and to take steps to limit potential health risks caused by the caterpillars. These caterpillars shed tiny hairs that can cause a skin reaction similar to poison ivy. When the hairs become airborne, they may be inhaled and cause trouble breathing.

As people head outside for recreation and yard maintenance, they face increased risk of contact with the toxic hairs. During the past two years, Maine Forest Service has seen evidence of browntail moth infestations in all Maine counties. The greatest risk for exposure to the toxic hairs is between April and July when the larger caterpillars are active. The hairs can land anywhere, including on trees, gardens, lawns, outdoor furniture, and decks. They also float in the air. The hairs remain toxic in the environment for up to three years. Activities such as mowing, raking, and sweeping can stir up the hairs.

Most individuals affected by the hairs develop a rash that lasts for a few hours up to several days. In more sensitive individuals, the rash can be severe and last for weeks. Inhaling the hairs may cause respiratory distress in some people. The rash and difficulty breathing result from both the toxin in the hairs and barbs on the hairs that cause them to become embedded in the skin and airways.

Treatment focuses on relieving symptoms and eliminating ongoing exposure. There is no specific treatment for the rash or breathing problems caused by exposure to browntail moth hairs.

Browntail moth caterpillars are easy to identify. They are dark brown with white stripes along the sides and two red-orange dots on the back. Younger caterpillars lack these white stripes.

Browntail winter web photo

Browntail moth winter web

Browntail moth cocoon photo

Browntail moth cocoon

Browntail moth caterpillar photo

Browntail moth caterpillar

Steps Mainers can take to protect themselves from browntail moth hairs:

  • Avoid places infested by caterpillars. Visit the Interactive Browntail Moth Dashboard to see activity in your area.
  • When performing activities outdoors that may stir up caterpillar hairs:
    • Aim for damp days or spray vegetation down with a hose. The moisture helps keep the hairs from becoming airborne while you are working.
    • Cover face with respirator and goggles.
    • Tightly secure clothing around the neck, wrists, and ankles.
  • Take cool showers and change clothes after outdoor activities in infested areas.
  • Dry laundry inside to avoid hairs embedding into clothing.

For more information: