It happens every year: When the weather warms up, the bugs come out to play—and this year has been no exception, from “seed ticks” to dangerous “kissing” bugs. And now, some very hungry caterpillars are triggering serious skin irritations.

Gypsy moth caterpillars are known for harming trees, but some recent incidents in Massachusetts prove that these pests can also cause red, itchy rashes, Boston 25 Newsreports. The red or white bumps appear on the skin after coming into contact with the caterpillars, and can last up to two weeks—and while not serious, they can cause annoying itchiness, similar to poison ivy.

“I didn’t even see the gypsy moth caterpillar but when I got home I had all red bumps,” one mother told Boston 25 News. “Just from putting my arms on the fence watching my son’s baseball game.”

Until last year, there hadn’t been a major gypsy moth caterpillar outbreak in the U.S. since the 1980s, and states like Massachusetts, Illinois, and Rhode Island are seeking solutions to prevent the insects from harming the environment as well as people.

Dr. Abigail Waldman, a dermatologist at Brigham and Women’s Hospital in Boston, explained that it’s the caterpillar’s hair that causes the rash. Your best bet? She advises families to stay as far away as possible if they spot the bugs.

“You can take an antihistamine for the itching,” she added, if someone does come in contact with a gypsy moth caterpillar. “Or for severe cases, you can get a topical steroid from your doctor.”

[h/t Fox 25 Boston]