1. Location is suburban Long Beach, CA. 5 miles from the beach.
  2. I started getting bit two weeks ago. I've got 12+ bites. They're very itchy red welts up to 1/2".
  3. The house has three broken foundation screens. For rodents to get in. I've never seen rats in the area.
  4. For 1 month I've occasionally heard banging type noises in the walls around my bedroom and the bathroom. It doesn't sound particularly like animals.
  5. The attic fans are screened. There aren't eaves on the house. Walking around the house, there's no sign of birds. I haven't seen or heard anything in the attic.
  6. It took 2 weeks of getting bit and looking before I found any mites.
  7. When empty, they look like a single piece of small translucent dust. Practically impossible to see unless crawling on a black surface and viewed within a foot with bright light and 20/20 vision. When full of blood, they're much easier to see. They look like black dots and can be seen when crawling. They're very slow, dumb, and clumsy. If you shake your shirt that will probably flick them off. They're difficult to crush (like fleas) when empty, but easy when full. If you're paying attention, you may be able to feel one crawling on you. In my case, they're attracted most to groin (underwear), feet/ankles (socks), armpits, and back of the knee. Biting mites like warm pockets of skin or where clothing fits tightly.

I found ~12 mites crawling around a crack where the wall meets the floor in the bathroom.

Several months ago I noticed a minor ant problem around the same crack. That crack is the only location in the house that I've identified as an insect source. The house is pretty clean and not much insects until recently.

In total, I've seen ~25 mites. All but one were in the bathroom. The other I felt crawling on my arm when I was lying on my bedroom floor.

My mom also started getting bites roughly at the same time as me. I found some carpet beetles around her bed area. Cleaned up the whole thing but the bites came back soon after.

Dad in the same bed as mom is not getting bit. Sister in the next room to me is not getting bit.

The wall is a separator between two bathrooms. Depiction:

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There's also an attic above and a crawl space below.

How should I control this rat mite or possibly bird mite infestation?

  • What form of pesticide if any would do well?
  • Seal the crack with caulk?
  • How to determine what is going on behind that wall? And find the animal.
  • Fix broken foundation screens around home.
  • Add screens to air vent openings.
  • I thought rat mites were in tropical areas. When I was in the military we used cloridane powder to kill them. Not available in the U.S. any longer but if you can get that it kills lots O bugs.
    – Ed Beal
    Commented Mar 23, 2016 at 1:01
  • 1
    Chlordane is pretty bad for humans (cancer). Try blowing boric acid powder into all nooks and crannies. Then you should seal them up too. Commented Mar 23, 2016 at 2:56
  • If you decide to blow boric acid, make you you do not breath in nor ingest any, it is poisonous. So wear glasses, a dust mask or respirator and wash your hands right away.
    – ajeh
    Commented Jul 27, 2017 at 16:25

3 Answers 3


Rat mites consume blood. They may be choosy about who they bite and not everyone has an allergic reaction to the bite.

This part may be unnecessary but I took everything out of my room and put it in the garage. I put the items in sealed contractor bags with a nuvan strip each. I hung a nuvan strip in the garage. I washed the floor, wall edges, all the nooks around the windows, and the crevices around the room with diluted pinesol.

I used boric acid along the edge of walls and in the bottom of dressers. To my knowledge, boric acid kills roaches either by being consumed and destroying their stomach bacteria or on contact by cutting open their exoskeleton (like what diatomaceous earth does). So for the latter reason it might have an effect on the mites. But it's not worth counting on.

For assurance, I sprayed Lysol around the edge of the walls and that kills the mites on contact.

I set a peanut butter rat trap in the crawl space. Several hours later I heard squeaking. There was one live and one dead rat trapped. I sprayed the area with Spectracide Bug Stop and got rid of the rats. I set a new trap and expect there are more rats.

I got 1/4" hardware cloth and I'm going to patch the broken foundation screens around the house. There's also two air vents that need to be screened to prevent further problems with birds/rodents.

The mites are a symptom of the rat problem. Once the rodents are controlled, the mites should dissipate.


I agree with Jimmy Fix-it. Caulk the floor seam, but more importantly caulk or cement the outside of the house. Getting in is the real problem, so don't let them in. Any crack, even a hairline crack, needs to be permanently sealed. Vacuum very frequently until no-one is getting bites any longer.

  • If they are already inside and feeding, it's beyond sealing cracks. Need to find proper insecticide and eradicate them too.
    – ajeh
    Commented Jul 27, 2017 at 16:25
  • Yeah maybe, if you can find them. But, you have to be careful with that stuff, some people have physical and even psychotic reactions. The little guys don't live long and even fleas can get vacuumed-up to wipe out the population in a week.
    – Iggy
    Commented Jul 28, 2017 at 2:54
  • We're assuming the rats are outside, I take it?
    – rogerdpack
    Commented Apr 20, 2020 at 4:56
  • Yepper, once they're trapped inside they're cut off and can just be cleaned away.
    – Iggy
    Commented Apr 20, 2020 at 8:15

Clove oil and sulfur dust. Plus a lot of work .Maybe lysol works.I have so many of them. It's hard to tell. Certianly nothing from home depot ect. Permethrin is ok maybe flex 10 10 .It depends on how bad the problem is. I think pest control people are scammers. Unless you have ants or roachs. Both easy to kill.They don't want to work after they get paid.

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