D.C. artist Michele Banks says she first began to feel the itch earlier this month after she had wandered around oak trees in search of squirrels to photograph — leaving her with redness, swelling and bumps on her skin.
She said she was probably bitten by oak mites and has gotten another bite since then. Although the itching subsided after about a week, she still has swollen bumps on her shoulders.
“At first I thought they were just unusually itchy mosquito bites, but once I read about the oak mites, I realized that was probably what they were,” said Ms. Banks, who manages a website called Artologica. “They just exactly fit the description — upper body, big red welts, very itchy, clear oozy bit at the center.”
While the cicadas may be gone, oak leaf itch mites that feed on cicada nymphs are making their marks now on residents in the D.C. region.
Dr. Rhett Kent, of Forefront Dermatology in Arlington, said 60% to 90% of his patients over the last two weeks have experienced mite bites.
“I’ve never seen anything [before] that I could say that was over 50% of the patient population having such any one [such] problem. So it is quite dramatic,” he said, adding oak mites are definitely “getting around.”
Other area residents this month tweeted pictures of shelves empty of anti-itch and anti-swelling medications at local pharmacies while grumbling about oak mite bites.
But insect experts are providing reassurance, saying the bugs should start to disappear in a matter of weeks.
Oak leaf gall mites or itch mites — formally called Pyemotes herfsi — are between 0.2 to 0.8 mm long, making them “virtually microscopic,” says Floyd Shockley, collections manager for the Smithsonian’s National Museum of Natural History’s Entomology Department.
While these mites are always around, they become “particularly abundant” in times and places where there is a periodical cicada brood emergence, he said.
Female cicadas in June lay their eggs that hatch in August and early September, Mr. Shockley said.
The presence of oak mites in either the District or Virginia has not actually been confirmed with any samples, said Eric Day of the Virginia Polytechnic Institute and State University’s Entomology Department.
But Mr. Shockley said he can confirm that oak mites are in the D.C. region although no samples have been sent for identification as far as he knows.
“In fact, they are widespread across most of the U.S., following the distribution of oak tree species closely as they feed on the immatures of a number of oak specializing insects,” he said, noting a variety of oak mites species.
He said the mites should start disappearing in September as nymphs, or immature insects, drop to the ground and burrow underground — thus, depleting the mites of their food source as colder weather moves in.
The mites could be dropping on people from trees or carried by the wind.
While it is difficult to know for certain what type of insect bit a person, Mr. Shockley said oak mite bites are similar to a “bad case” of chiggers, also known as red bugs or harvest mites, but tend to be near the head and on the arms rather than on the lower body.
The bites cause small bumps that turn into itchy blisters and can last about two weeks. They can turn into painful, itchy rashes when there are a large number of them.
“Some people have very severe bites, and some people have very mild bites so there is a big spectrum of response,” said Dr. Kent, the dermatologist. “But in the case of the oak mites, almost everyone is having an exuberant redness, some blistering in the center. So it is definitely a more severe end of the spectrum type of bite that we’re dealing with right now.”
Mr. Shockley said the best way to avoid these bites is to not hang out under oak trees for the next three to six weeks — advice that Ms. Banks is taking.
“I’m still taking squirrel photos most days, but I’m trying to avoid oak trees,” the full-time artist said. “Luckily, the parks where I go also have walnut and osage orange trees, and the squirrels like those, too.”
People are turning to over-the-counter hydrocortisone to treat bites, but Dr. Kent said that medication is not strong enough for more “robust reactions.”
For more severe reactions, he recommends a prescription-grade topical steroid and also oral non-sedating antihistamines such as Allegra or Zyrtec for bites that turn into rashes.
Oak mite bites shouldn’t be a major problem again until 2038, when the next emergence of cicadas is set to occur, said Mr. Shockley, noting that it is possible for outbreaks involving other insects that mites might feed on to occur.