An invasive species of caterpillars are causing people to break out in painful rashes in Maine and Massachusetts.

The Maine Center for Disease Control and Prevention, which has declared a public health nuisance, said the browntail moth caterpillar is found only on the coast of Maine and Cape Cod.

The creepy crawlers are easy to identify: They're brown, about 1.5 inches long, white stripes along each side, and two red/orange spots on their back.

The agency said the poisonous hairs of the caterpillar could cause dermatitis, which is similar to poison ivy.

The rash can occur upon contact with the skin or if the caterpillar's hairs become airborne if dislodged from a living or dead caterpillar.

"Most people affected by the hairs develop a localized rash that will last for a few hours up to several days, but on some sensitive individuals, the rash can be severe and last for several weeks," the agency said. "The rash results from both a chemical reaction to a toxin in the hairs and a physical irritation as the barbed hairs become embedded in the skin."

If you inhale the hairs, it can cause respiratory distress, the agency said.