-- Tiny biting mites that cause a BIG itch --
Summary: Pyemotes itch mites (=pymotes itch mites) are very tiny biting mites that can inflect a very annoying bite, completely out of proportion to their tiny size. Bites look like a inflamed itchy rash. These mites normally parasitize insects that feed on grain or seeds but will bite people that encounter the mites. The mites do not burrow into skin nor do they infest homes. Avoiding the mites in the first place is the best defense but skin lesions can be easily treated with OTC medications.
Common misspelling: pymotes itch mite
Pyemotes itch mites are tiny, nearly microscopic mites that normally feed on (parasitize) a variety of insects, not on us. If, however, they happen to get on us, usually through handling of infested grain or straw, these mites can inflict bites that cause red, swollen and intensely itchy skin lesions. The redness and irritation can last for days but is not otherwise dangerous.
Bites from pyemotes mites tend to happen in very specific situations, the mites DO NOT infest homes. Bites most often occur when we come into contact with insects that are infested with these mites. For example, a condition called "straw itch" occurs when people who handle straw, such as when feeding livestock, develop an itchy rash from the pyemotes mites that are infesting the insects living in the straw.
In another example, a few years ago people in several mid-western states developed a mysterious itchy, red rash after working outdoors. Investigators found that the rash was caused by bites from pyemotes mites that were infesting the insects that make oak leaf galls, the condition is now called "oak leaf gall itch". Affected people had worked under oak trees which "rained" mites from their infested leaves - mystery solved!
Photo: CDC, A. Broce, L. Zurek, Kansas State Univ.
There are no insecticide treatments available for pyemotes mites and repellents containing DEET are not particularly effective. Your best defense is to avoid situations where exposure to the mites is likely, such as handling straw, and to wash thoroughly if exposure is suspected. Mites are easily washed off with soap and water. By the time the itchy, red lesions develop the mites may be long gone but washing at this stage is still a good idea.
OTC medications for itch are usually adequate to treat bites. Obviously you should seek medical attention for any infection that develops. Normally bites should clear up in a few days.
Pyemotes mites are nearly microscopic so it is unlikely you'll see one and since their bite in painless you won't know anything is wrong until the rash and itching starts.
If you could see one of the mites close-up it would look like the drawing below, from the 1967 CDC publication "Pictorial Keys To Arthropods, Reptiles, Birds And Mammals Of Public Health Significance". Notice the slender body, pointed at both ends, wide separation between two pairs of front legs and two pairs of back legs, and numerous body hairs (setae).
The bite symptoms are very similar to those caused by chigger mites, and the two conditions can be easily confused. Both mites are nearly microscopic and both cause similar inflamed itchy rashes.
Professional-level pest control supplies are generally not available in home and garden stores but can be found at DoMyOwn.com, our affiliate.
This DK Smithsonian Handbook is an excellent general guide to insect identification (available through Amazon, our Affiliate):
For additional resources see our Insect Identification article.
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