Here’s what to do about the irritating rash caused by the browntail moth caterpillar

By Julia Bayly, Bangor Daily News Staff

This summer is predicted to be a bad one for browntail moth caterpillar outbreaks in the state. Now, as more Mainers are spending more time outside, it’s looking like that prediction is coming true.

That’s left folks turning to social media and pharmacies in search of anything to cure the painful skin rash caused by the hairs of this invasive species.

Browntail moth caterpillars have poisonous, irritating hairs that can cause a blistery rash similar to poison ivy when people come into contact with them. The hairs also can cause respiratory distress if people breathe them in. The moth has been declared a public health nuisance in the state by the Maine Center for Disease Control and Prevention.

Not only are there more browntail moth caterpillars in the Pine Tree State this summer, but their range is expanding. They have been reported in all 16 counties. 

“We have had people coming in looking for remedies,” said Christine Cattan, a pharmacist at Bangor Drug Company. “It can be hard to diagnose just by looking because [the rash] kind of looks like prickly heat but it does have a characteristic mottled looking effect.”

Once it is confirmed, the good news is there are treatment options easily available, according to Cattan.

“Any sort of antihistamine will help,” Cattan said. “I also recommend people use a nice hydrocortisone cream with aloe to soothe the irritation.”

Before doing anything though, Cattan said you should wash the affected area. Applying ice packs and taking ibuprofen can also help, she said. Before going to bed, taking a bath with  Aveeno Soothing Body Wash can help reduce the itchiness so you can sleep. Cattan did caution that Aveeno can make the bathtub slippery so to be careful your soothing soak does not end in a fall.

“Some people like to use witch hazel as a topical,” Cattan said. “That can be soothing but it can also dry your skin out and it is not long lasting, but it will serve to quickly neutralize the area right away.”

There’s also a compound, shared by Maine General Medical Center, that can be made at home from over the counter substances. That combines the best of all ingredients, according to Cattan.

The compound calls for combining a quarter cup of witch hazel, one-half tube of hydrocortisone cream, a half tube of diphenhydramine and a quarter tube of Aspercreme or lidocaine cream mixed together in a plastic spray bottle. Shake well and apply on the affected area.

“This mixture is pretty smart,” Cattan said. “It really covers everything — the lidocaine is a numbing agent, the witch hazel will give immediate relief and you get the long term relief from the diphenhydramine and hydrocortisone.”

Cattan does caution to never use a topical and oral diphenhydramine — like Benadryl — at the same time.

“The topical form absorbs into your system and if you take it orally, you can get quite drowsy,” Cattan said. “Use one or the other.”

If over the counter medications don’t work, Cattan said to see a doctor. They may prescribe a stronger lotion compound. 

Risk of exposure to browntail moth caterpillars in Maine is expected to run through July.