Browntail Moth Rash and Infestation – Get the Facts Now

NOTE: If you are currently suffering from the browntail moth rash and are looking for relief, please have your doctor or urgent care center call in a prescription for “browntail moth rash spray” or “browntail moth rash lotion.”

To speak with a pharmacist, call (207) 899-0886 or email [email protected]. Relief is in sight!

Learn More About Our Rash Spray and Lotion

The browntail moth has been getting much attention because their numbers have spiked to a level we haven’t seen in quite some time. 

Why do we care so much? Because the toxic hairs shed by browntail moth caterpillars can cause a severe rash or respiratory issues for those who encounter them. These hairs are easily encountered once they become airborne. Many people don’t even know they are being exposed because the hairs are so small. 

2023 Maine Update

The Department of Forestry has spotted webs in every county in Maine. The highest concentration continues to be along the coast; however, they continue to move westward.

Visit the Maine Forest Service’s news section for the most up-to-date information.

Subscribe to Updates from the Department of Agriculture, Conservation, and Forestry

Weather Forecast

The weather plays a huge part in hair activity. Dry and windy weather sets the hairs in motion. Considering the heavy rain we experienced in June, we haven’t seen abnormally high numbers of rash sufferers. One bright side to the horrible weather!

The previous year also plays a role. In particularly wet springs, a fungus can develop, which kills the caterpillars. This means they will not turn into moths and lay lots of eggs for hatching the following year. That is substantial since each moth lays 25-400 eggs. We hope that this year’s rain will lead to a reduced level of infestation in 2024!

The Cause of the Health Issues

Throughout much of their life cycle, the moth sheds its toxic hairs which become airborne or attach to leaves and brush. When the barbed hairs contact our skin or lungs, they can cause itchy painful rashes or respiratory issues. Issues are reported most in June and July when the toxin concentration in mature larvae is at its highest.

Browntail Moth Life Cycle

Skin Reactions

Browntail Moth Skin Rash - Photo courtesy of Wikimedia Commons most common reaction occurs when the caterpillar hairs contact the skin. This can cause both chemical reactions to the toxins and physical irritation when the hairs get embedded in the skin. The chemical reaction, referred to as dermatitis, produces a severe rash similar to poison ivy. Symptoms include itchy, blistered and swelled skin. The rash itself is not contagious. It’s caused by a reaction to the toxins that are in the hairs. Unlike the oil of the poison ivy plant, the hairs are not likely transferred to others through physical contact.

Respiratory Issues

Respiratory issues are less common but can be particularly problematic for asthmatics. If you have asthma, you should carry your inhaler with you when spending time outside, especially during windy conditions. If you choose to be outside under these conditions, you may want to wear a mask that covers your nose and mouth.

If the hairs get caught in the mucosal areas of the mouth or throat they can cause burning, irritation or itchiness. Symptoms may be relieved by taking liquid Benadryl which helps counter the histamine reaction that the hairs can cause. However, you are encouraged to seek medical attention.

Symptoms can appear within hours of contact. If you think you’ve developed a reaction, make an appointment with your doctor as soon as possible to discuss treatment options.


Browntail Moth Rash Spray and Lotion with Woman Scratching Arm

There is no antidote for the toxins, so treatment is focused on relieving symptoms and eliminating further exposure. We make a prescription-strength topical browntail moth medication which has been shown to significantly reduce discomfort from the rash. The compound is available, by prescription only, in both lotion or spray form. The spray is especially beneficial in treating these types of rashes because they are painful to touch. For those who have an acute case, a short course of oral corticosteroids may be prescribed.

Since many reactions occur over weekends, seeing a doctor may not be immediately possible. In these cases, you may find relief by soaking in a warm bath and applying calamine lotion or antihistamine cream. Also, try the over-the-counter formulation below.

You can also make an over-the-counter version of our prescription-strength lotion. Although not as strong as our compounded lotion, it may provide some relief.

OTC Lotion

Combine equal parts of the following creams:

  • hydrocortisone 1% (e.g. Cortizone 10)
  • diphenhydramine hydrochloride 2% and zinc acetate 0.1% (e.g. Extra Strength Benadryl),
  • lidocaine 4% (e.g. Aspercreme)

OTC Spray

In a spray bottle, combine equal parts of the following cremes and fill the rest of the bottle with witch hazel.

  • hydrocortisone 1% (e.g. Cortizone 10)
  • diphenhydramine hydrochloride 2% and zinc acetate 0.1% (e.g. Extra Strength Benadryl),
  • lidocaine 4% (e.g. Aspercreme)
  • witch hazel

Read About Our Prescription Rash Treatment


There are several actions you can take to reduce your risks.

  • Avoid places that appear to be infested. Indicators include vacated nests and defoliated trees and shrubs.
  • Wear a respirator, protective eyewear, and cover exposed areas of skin. This is important on windy days or when performing activities that would stir up hairs such as lawnmowing or raking.
  • Wipe or rinse off lawn furniture before sitting in them.
  • Cover your skin and wear eyewear when driving through infested areas in an open-air vehicle.
  • Close your car windows when driving through an infested area.
  • Do yard work on damp days or spray the area your working in. Moisture will help keep the hairs from becoming airborne.
  • Blow window fans outward instead of inward. You may not get the benefit of the breeze, but it will pull hot air out and will prevent pulling hairs in from outside.
  • Don’t dry laundry outside. Hairs can become embedded in clothes and cause reactions when you wear them.
  • Wash exposed clothes (not with unexposed clothes) after spending time in an infested area to remove embedded hairs.
  • Take a long cool shower after spending time in an infested area.
  • Use duct tape to remove any hairs that may have embedded while outside.
  • Remove nests. This should only be done in winter or early spring, while the larvae are dormant. Many nests are too high for the average person to remove, so check with an arborist to see if they offer nest removal service. View a list of licensed arborists willing to prune winter nests or a list of licensed pesticide applicators willing to treat browntail moth.

2020 Exposure Risk Map from the Maine Forest Service

Click the image below to view the full map on the Maine Forest Service’s website. Watch the MFS website for the 2021 map.

2020 Maine Browntail Moth Exposure Risk Map

How do you know they’re in the area?

Browntail Moth Nest - Photo courtesy of Wikimedia Commons area of infestation has previously been in the southern coastal part of the state, however, the area of infestation continues to grow. View the Maine Forest Service’s risk map for the latest status (the map for 2021 should be out soon).

Their nests are noticeable webs that are typically found in oak or apple trees. They appear in the fall and shelter the larvae through winter. In spring, hundreds of larvae can emerge from each nest to start wreaking havoc on trees and humans.

The best indicators of browntail moth infestation are vacated nests and trees and shrubs with a lot of missing leaves.

Resources and More Information

About the Author

Kim Crabb

Coastal Pharmacy & Wellness Staff

Kim is the marketing director at Coastal Pharmacy & Wellness and has been in the pursuit of wellness for decades. She led a workplace wellness program for over 12 years where she discovered that she loved helping people make positive healthy changes. You can often find her mired in information rabbit holes while researching answers to seemingly straightforward questions. It's ok; she loves it because it means she can share new-found knowledge with lovely people like yourself!


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