Bug spray won't protect you from itchy mite bites linked to cicada invasion. Here's what to do instead

That itchy bug bite on your leg might not be from a mosquito. In fact, it could be from an oak itch mite, which feed off cicada eggs -- and bug spray can't stop them.

“We have seen a significant increase in our suburban locations compared to our downtown office, and this is presumably because that’s where the cicadas were,” Dr. Jordan Carqueville, medical director of The Derm Institute of Chicago told NBC Chicago.

According to cicada expert Dr. Gene Kritsky with Mount St. Joseph University, a particular mite known as the "oak leaf itch mite" can be seen in large amounts following a cicada emergence.

Kritsky noted that in 2007, "people in Chicago who had oak trees in the yards, started to complain of bites after the cicada emergence."

"It turned out that the oak itch mite was found in the egg nests of Brood XIII cicadas," Kritsky told NBC Chicago.

That same brood was one of the two to emerge in Illinois during 2024's historic event, which Kritsky described as "biblical."

But while the periodical cicada emergence appears to have significantly declined, making way for the annual "dog day cicadas" now emerging across the region, the eggs laid months earlier are now leading to a rise in mites.

“This is actually sort of the last hurrah, if you will, of the cicada emergence is to cause this itchy irritation," Kritsky said.

For those who experienced large amounts of cicadas in this emergence, there are likely thousands of eggs still left to hatch.

The hatching takes place between six and 10 weeks after eggs are laid. And not only can it take hours to notice after an oak itch mite bite, but the rashes can last for a couple of weeks.

“You can probably see that red rash with the bump for up to two weeks with symptoms of itch, and we recommend people use the over-the-counter anti-itch treatments,” Carqueville said. “Despite how itchy they are, do not scratch. Because if you scratch a lot, you can get breaks [in] the skin, and that just creates a port of entry for bacterial infections.”

You should avoid being under oak trees, according to the Illinois Department of Public Health, which also recommends keeping your windows closed because the mites are so small they can “pass through window screens.”

The Illinois Department of Public Health’s website also states “DEET and other insect repellents may not work” on the oak itch mites… and they could even bite you through loosely-woven clothing.

What happens if you are bitten by an oak leaf itch mite?

The Illinois Department of Public Health noted that mites typically require about four hours on someone's body before biting.

“These bites will give you a mild rash, something that will cause some itching and discomfort," said Dr. Ben Flagel, emergency department director for Endeavor Health Swedish Hospital.

How to know if you've been bitten by an oak leaf itch mite

According to IDPH, the bites resemble "red welts that look like chigger bites on your neck, face, arms and upper body."

"These bites are not usually on legs where chigger bites may be found," IDPH reported. "The itch mite welts form into a pimple-like lesion after about 12 hours. The bites are very itchy and can be present for up to two weeks."

Can you treat or prevent mite bites?

Health officials say the most important thing is to avoid itching or scratching bites.

IDPH suggests over-the-counter topical anti-itch creams or oral anti-histamines can help control the itching, but if the itching grows too intense or it appears an infection has formed, officials urge you to contact a health care provider.

“The concern is if you’re itching them too much, that you can break the skin and that you can get a bacterial infection," Flagel said.

Controlling oak leaf itch mites can be tricky, on the other hand, as many sprays don't target the parts of trees where the mites develop.

"There are mixed results from the use of DEET (a mosquito and tick repellent)," Penn State reported. "People can best protect themselves by limiting their time from under infested trees and by immediately removing and laundering clothing and then showering."

IDPH suggests the following tips for preventing bites:

• If you see brown and crusty edges on oak tree leaves, be aware that mite activity is possible. Don’t sit under oak trees or on nearby lawns.
• If you are in an area where itch mite associated rashes are occurring, or nearby oak trees have brown and crusty edges:
  • When weather permits, keep windows shut from August through October when “mite-showers” can occur.
  • Remove clothing items each day and launder them. Take a warm, soapy shower after coming indoors, especially after gardening, raking leaves or performing other outdoor activities.

How long should you watch for the mites?

According to researchers, the bites most often occur in late summer and fall, when the mite populations are often at their highest.

"People should avoid sitting under the trees until after the eggs hatch in mid-August," he said.