Dust mites vs bed bugs: how to tell them apart
By Jill from MiteGuard · Tips & Advice · Last updated 5 November 2026
Dust mites and bed bugs aren't the same thing. Bed bugs are insects you can see (DermNet NZ compares adults to an apple seed), and they bite. Dust mites are too small to see without a microscope and they don't bite. When dust mites bother people, it's an allergy to proteins in their tiny droppings, not a bite.
It usually comes up on a quiet morning. You strip the bed, notice a few itchy spots on your arm, and the late-night Googling starts. Is it the mattress? Is it mites? Is it something worse? The good news is the two are quite easy to tell apart once you know what you're looking for.
In short
- Bed bugs are small, flat, reddish-brown insects. Adults are around 4 to 7 mm long (Health NZ), so you can see them.
- Dust mites are microscopic. You won't ever see one on your sheets.
- Bed bugs bite. Dust mites don't bite or pass on disease.
- Dust mite trouble is an allergy, usually to a protein in their microscopic waste.
- Bed bugs leave visible signs: live bugs, shed skins, eggs and small dark marks.
- For bed bugs, you could hire a pest control expert. For dust mites, it's about lowering exposure day to day.
Dust mites vs bed bugs at a glance
| House dust mites | Bed bugs | |
|---|---|---|
| Size | Microscopic | Adults about 4–7 mm (Health NZ); eggs about 1 mm |
| Can you see them? | No, not without a microscope | Yes, adults are reddish-brown and visible |
| Do they bite? | No | Yes, usually at night |
| Where they live | Mattresses, bedding, carpets, anywhere people live, especially warm and moist spots | Dry, dark hiding spots: mattress seams, headboards, bed frames, furniture, drapes, cracks in walls and floors |
| What they feed on | Mainly flakes of dead skin | Blood of sleeping people and animals |
| Signs | No visible signs; some people react to the allergen | Live bugs, cast-off skins, white eggs, small dark brown or black marks, itchy bites |
| What helps | Hot weekly washing, lower indoor moisture, zip-closed dust mite covers | Find where they're hiding, hot wash and dry, and call a pest control professional |
Myth vs fact
| Myth | Fact |
|---|---|
| "Dust mites bite." | Dust mites don't bite or pass on disease. Reactions come from allergy to their waste. |
| "If I can't see anything, it must be bed bugs hiding." | Adult bed bugs are big enough to see, and they leave signs like shed skins and dark marks. |
| "Itchy spots in a line prove it's bed bugs." | Bites alone can't confirm bed bugs. Other insects and skin conditions can look similar, and some people don't react to bed bug bites at all. |
| "A hot wash of the sheets will sort bed bugs out." | Heat kills bed bugs, but they often hide in furniture and walls, so you need to find where the infestation actually is. |
Can you see dust mites or bed bugs?
This is the quickest way to tell them apart.
You can see bed bugs. Health NZ describes adults as reddish-brown with a flat, oval body around 4 to 7 mm long. Young ones look similar, only smaller, and the eggs are white and around 1 mm. DermNet NZ gives a wider range, 5 to 15 mm (around the size of an apple seed), so treat size as a rough guide. If you've spotted something crawling along a mattress seam, it's not a dust mite.
You can't see dust mites. Healthify NZ calls them "tiny bugs, too small to see without a microscope". They live wherever people do, and that's why you'll never spot them on the pillowcase, however hard you look. We've written more on this in Can you see dust mites?
Bites vs allergy: what's actually going on?
This is where most of the mix-up happens.
Bed bugs bite. They feed on the blood of sleeping people and animals, usually at night. Health NZ says most people get a series of itchy bites a bit like mosquito or sandfly bites, and these might not show up until a few days later. Some people don't react at all. Bite marks on their own aren't proof, either. DermNet notes that bed bugs can't be identified from the bite alone.
Dust mites don't bite. Healthify NZ is clear on that. What some people react to is a protein found in the microscopic waste of dust mites. Healthify notes that many people with asthma, eczema and hay fever are allergic to it. That's an allergy, not a bite, so the "dust mite bite" you might read about online isn't really a thing. There's more in Dust mite bites: real or myth?
If you've got bites, a rash or anything that's worrying you, have a chat with your GP or pharmacist. They can help work out what's going on. Health NZ says bed bug bites are not usually dangerous, but in very rare cases people can have a severe allergic reaction called anaphylaxis. That is a medical emergency: call 111 immediately.
Where do dust mites and bed bugs live?
They like quite different spots.
Dust mites like it warm and moist. Healthify NZ lists mattresses, bedding and carpets, and says they feed mainly on the flakes of dead skin we shed every day.
Bed bugs like it dry and dark. Health NZ lists mattresses, headboards, bed frames, furniture, drapes, and cracks in walls and floors. They can't fly, but they can crawl short distances, so it's worth checking other bedrooms too.
How to check for bed bugs: take the sheets off and look along the mattress seams and the bed frame with a torch. Health NZ says to look for live bugs, cast-off skins, eggs, or small dark brown or black marks. If you find nothing like that, you're probably not dealing with bed bugs.
What actually helps with each?
They need different approaches, so it's worth knowing which one you've got.
If you think you have bed bugs
- Wash and dry bedding and clothing at high temperatures. Health NZ notes heat kills bed bugs.
- Work out where they're actually hiding. They often tuck into furniture and walls, not just the bed.
- Get expert help. Health NZ suggests a pesticide from the hardware store or supermarket, or you could hire a pest control expert. Infestations can be stubborn. DermNet notes many bed bugs are now resistant to pesticides, and repeat visits are often needed. A good pest controller is the right person for this job.
If dust mites are the concern
Healthify NZ suggests a few simple things:
- Wash sheets, pillowcases and duvet covers once a week on a long, hot (over 60°C) cycle.
- Keep moisture down with ventilation or a dehumidifier, and skip humidifiers in bedrooms.
- Use dust mite covers on the bed. Healthify describes them as a very efficient way to keep dust mites inside the mattress and stop their food supply getting in.
Where a MiteGuard cover fits
A MiteGuard cover is a physical barrier for dust mites. It's NZ-made from tightly woven cotton with a 3.5 micron weave, lab-tested, and it zips closed to fully enclose the mattress, pillow or duvet. Your regular sheets and duvet cover go over the top, so the bed looks much the same. MiteGuard is endorsed by Allergy NZ and Asthma NZ.
Helps reduce exposure to house dust mite allergen. Not a cure.
To be clear, MiteGuard is made for dust mites. If you've found bed bugs, deal with those first, and a pest control expert can help.
FAQ
Are dust mites and bed bugs the same thing?
No. Bed bugs are insects you can see that feed on blood. Dust mites are microscopic, feed mainly on flakes of dead skin, and don't bite.
Do dust mites bite like bed bugs?
No. Dust mites don't bite. Itchy bites that appear overnight are more likely to be something else, such as bed bugs or another insect. Your GP or pharmacist can help work it out.
How do I know if it's dust mites or bed bugs?
Look for physical signs. Bed bugs leave live bugs, shed skins, white eggs and small dark marks around mattress seams and the bed frame. Dust mites leave nothing you can see.
Should I call pest control for dust mites?
Dust mites live wherever people do, so it's about lowering exposure: hot weekly washing, keeping moisture down and zip-closed dust mite covers. Pest control is the right call for bed bugs.
About the author Jill from MiteGuard writes for MiteGuard, a New Zealand business making zip-closed cotton dust mite covers. Last updated 5 November 2026.
References
- Health New Zealand | Te Whatu Ora. Bed bugs. https://www.healthnz.govt.nz/health-topics/keeping-healthy/healthy-homes-environments/insect-bites-and-pest-control/bed-bugs
- Healthify NZ. Dust mite allergy. https://healthify.nz/health-a-z/a/allergy-dust-mites
- DermNet. Bed bugs. https://dermnetnz.org/topics/bed-bugs