Mite bites can cause skin lumps and rashes and, occasionally, more serious reactions, Dr. Merchant says.

Among outdoor mites, the only type that frequently bites people is the chigger. The word “chigger” applies to a particular species of mite that bites during its larval stage of development, and their bite produces an intensely itchy red welt, Merchant explains. “There are not too many other mite problems outdoors,” he adds.

When it comes to indoor mites that bite or cause health issues, Merchant says most come from animal nests. “Some mites will infest the nests of birds and rats and mice, and when they become abundant, they’ll leave that site and sometimes wander into the house and bite people,” he explains. In most cases, the bites of these mites cause an itchy skin rash, which may produce small lumps or pimples.

“The skin might be very itchy or red for a few days, but that will taper off,” Merchant says of mite bites. Ice and anti-itch creams like hydrocortisone can control the swelling and itching. But those symptoms should resolve within a week, he says. (Nearly all species of biting house mites cannot live on human beings, and so they don’t “infest people,” he adds.)