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What to Know About Oak Leaf Itch Mites

Medically Reviewed by Jabeen Begum, MD on December 01, 2021

While, to many, fall is as good a season as any other, it can be the worst for those who are prone to oak leaf itch mites. These are commonly known to feed on larvae of an oak gall midge (fly) that live on the edges of pin oak leaves. From late July to early fall, these mites drop from the tree after completing their development, landing on animals and humans and biting them. This bite causes a rash-like and itchy reaction which, at times, can be intense.

What Are Oak Leaf Itch Mites?

Scientifically known as Pyemotes herfsi, oak leaf itch mites are nearly invisible to the naked eye (0.2 mm in length), but they are responsible for mite bite outbreaks in several states across the country during the fall. Some facts about this microscopic creature:

  • A single female can produce 200 to 300 eggs.
  • Once hatched, larvae take only a week to reach adulthood.
  • Cooler temperatures and moist conditions can increase population growth.
  • A single large pin oak tree can rain down up to 400,000 oak leaf itch mites per day.
  • Oak mites can live through the winter in protected areas or within leaves/leaf litter on the ground.

Oak mites feed on larvae of a midge (fly), which forms galls on the edges of pin oak leaves. Specialists also think that oak leaf itch mites feed on cicada eggs. It could be the explanation behind an increase in the cases of mite bites to humans. 

How Do Oak Leaf Itch Mites Bite Humans?

If you have been bitten by the oak leaf itch mite, you most likely got the mites from a tree with insects that the mites feed on. Sitting, walking, hiking, etc. under such a tree could expose you to the mites. Sometimes, the mites will be blown off the host tree and land on you. 

The fact that the mites are so small means that they can be blown over long distances by wind, so you can get bitten by oak mites that are not even from your local area. If there are pin oak trees near where your pets like to walk, you may get the mites from the fur of a dog or cat that has wandered off to play among infested leaves.

In most cases, the itch mite will bite you anywhere in your upper body around the neck, shoulders, arms, and chest. The oak mite’s bite itches in a manner similar to a mosquito’s. You may not notice that you’ve been bitten until 10-16 hours later. That’s when you notice raised, red areas with a small central blister. Other symptoms include:

  • Itchiness (which may worsen during bedtime)
  • Oak mite rash that may appear red and be painful to scratch 
  • Small, raised, pimple-like bumps

What Is the Treatment for Oak Leaf Itch Mite Bites?

If you’ve been in close contact with infested pin oak leaves, immediately remove and wash your clothes and then take a shower. Avoid scratching where the mite has bitten you to avoid a bacterial infection. You may use an over-the-counter itch cream to ease the discomfort. Your doctor may recommend:

  • Cortisone cream
  • Calamine lotion
  • Claritin (10 mg daily)
  • Hydrocortisone 1% cream or ointment
  • Other antihistamines

How Do You Prevent Oak Leaf Itch Mite Bites?

Miticides are not effective against oak leaf itch mites because mites are usually hidden within leaf folds where they’re well protected. You can’t use insect repellents on your skin hoping not to be bitten by oak mites. 

The best way to prevent oak mite bites is to stay away from pin oak trees in the fall. If you live near infested trees, keep your windows shut to keep the mites away from the house. 

Also, watch out for brown and crusty edges on oak tree leaves, as they could indicate mite activity. Don’t use a blower to collect oak leaves, as this may spread the mites to everyone in the vicinity. If you must come into contact with infested oak leaves, wear rubber gloves and a long-sleeved shirt. 

The food source for oak mites starts to deplete by the end of August. As a result, oak mite bite outbreaks end around this time.

Show Sources

SOURCES:

Illinois Department of Public Health: “2007 Outbreak of Human Pruritic Dermatitis in Chicago, Illinois Caused by an Itch Mite, Pyemotes herfsi.”

Kansas State University Agricultural Experiment Station and Cooperative Extension Service: “Oak Leaf Itch Mite.”

PennState Extension: “Oak Leaf Itch Mite.”

University of Maryland Extension: “Oak Leaf Itch Mites and Periodical Cicada Eggs.”

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