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Identifying Fleas vs. Bed Bugs

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Author Image Written by Brenda Woods Updated 04/19/2024

Suffering from an itchy, swollen bug bite can be painful and annoying—especially when it happens continuously. The best way to prevent future ones is to know what exactly is biting you. Fleas and bed bugs are common culprits, but they are very different infestations that require substantially different treatments.

Here, we’ll show you how to identify a flea and a bed bug based on their appearance, bite, and more. If you have a flea problem, you may be able to get rid of the insects with careful cleaning and veterinary drugs. However, if it’s bed bugs that are biting you, you’ll likely need to call in a professional pest control company.

Fleas vs. Bed Bugs: Appearance

Fleas and bed bugs are both small, reddish-brown, blood-sucking pests. While it’s unlikely you’ll get the opportunity to look at them side by side in real life, it’s helpful to know the difference between how the two look. If you want to be sure, stick the bug on a piece of tape and hold it against a white background to get a better look.

Fleas are oval-shaped pests that are less than 1/8 inch long (1.5–3 mm). Bed bugs, however, have a flatter seed-like shape and measure less than 1/5 inch long (less than 10 mm). In general, bed bugs are slightly larger, but it’s difficult to tell the difference at first glance.

Fleas vs. Bed Bugs: Host

Fleas and bed bugs differ in their choice of host. Fleas prefer to feed on hairy animals like dogs and cats, while bed bugs prefer to bite humans. Because of this, it’s likely that if your home has fleas, your pet brought them in, and if your home has bed bugs, a person brought them in—usually on a piece of clothing, furniture, or luggage.

That’s not to say fleas will never feed off people and bed bugs will never feed off animals. If they need to, each pest will feed off their second choice to survive. However, if your furry pet is frequently scratching, that’s a likely sign that feas are the problem.

How They Move

Fleas are known to jump an impressive distance—13 inches horizontally and 7 inches vertically. Bed bugs can’t jump and instead move by crawling.

Where They Hide

Both fleas and bed bugs are nocturnal. Fleas will cling to their host, likely your cat or dog, and hide there when not feeding. Bed bugs will scurry into your mattress, box spring, and bed frame during the day to stay out of sight. You will often see bites or droppings before you see a live insect.

While bites alone aren’t the best indicator of which pest you’re dealing with, there are some key differences between flea bites and bed bug bites.

Flea bites immediately swell up and start itching. Worse, if you’re allergic, you may get hives or a rash, and the bite may blister. Be careful not to scratch it—if the blister breaks, it may become infected. Sand fleas can burrow into the skin, but these species are typically only found in tropical regions outside the U.S.

Unlike flea bites, you probably won’t notice a bed bug bite until much later. You may feel a slight burning sensation before the itching starts. The red welts may not appear until 48 hours to a week after you were bitten. If it’s bad enough, your bite may become inflamed.

When fleas bite people, they tend to go after warm, moist areas like the bend of your elbows and knees, or your armpits and other folds in the skin. Since they may jump up onto your skin from the ground, flea bites often cluster on the feet and ankles.

Bed bugs, on the other hand, bite exposed skin on your upper body, typically your face, neck, and arms. Since they infest mattresses and feed at night, they head for areas that are exposed while you are asleep beneath sheets and blankets.

Flea bites look like groupings of mosquito bites, often in clusters of three. They can turn into blisters or open sores in about three days. Bed bug bites often leave three or four bites in a row or straight line, along the edge of a sheet or hemline, but not always.

Because of how fleas puncture your skin, there may be a dark red center in the middle of the bite. Bed bug bites will look like raised welts from the allergic reaction people have to the pests’ saliva. Bed bug bites tend to be slightly larger than flea bites.

Fleas will bite often, whenever they get the chance for a meal. Bed bugs don’t need to feed as frequently. They eat about once a week, or every five to 10 days.

Except for the case of an infection, when you may need to see your doctor, flea bites and bed bug bites are easy to treat. Resist the urge to scratch, which could damage the skin and lead to an infection. For flea bites, apply a calamine lotion or anti-itch cream. An ice pack and oral histamine may reduce the swelling. Treat a bed bug bite with a topical steroid.

If a flea bite or bed bug bite doesn’t go away after a week or two, call your doctor.

Fleas vs. Bed Bugs: Lifespan

Generally, an adult flea will live for about three months, but under ideal conditions, they could live as long as 18 months. A female flea will lay up to 50 eggs a day. Bed bugs have a much longer lifespan. Adult bed bugs can live for about six months to a year. A female bed bug can lay up to 500 eggs in her lifetime.

Fleas vs. Bed Bugs: Disease

Fleas can spread diseases like typhus and tularemia, while bed bugs are not known to transmit any.

Signs of an Infestation

Since bed bugs and fleas are so hard to tell apart at a quick glance and their bites often look similar, be sure to look for these other signs of infestations.

  • Multiple visible fleas on your pet or in your home
  • Clear, yellow flea eggs on your pet’s fur
  • Dark black specks of feces on your pet’s fur or bedding
  • Changes in your pet’s health
  • Changes in your pet’s behavior, like anxiety or itching
  • Visible bed bugs
  • Rust-colored bed bug excrement
  • Bed bug exoskeletons
  • Musty or sweet odor

Fleas vs. Bed Bugs: Treatment

Generally, the treatment of fleas is easy, as they usually cluster around pets and prefer to live outdoors. Bed bugs, however, are a different story.


If your pet has fleas, take it to the veterinarian to explore your options for flea medicine. Many types kill fleas at all stages of the lifecycle and are waterproof. Wash your pets’ bedding and toys, and you should be rid of fleas. Put your pet on a preventative medication to keep the problem from coming back.

At the same time, give your home a thorough cleaning, especially around areas where pets sleep. Vacuum frequently and thoroughly, removing and throwing away the vacuum bag outdoors as soon as you’re done. Steam cleaning carpets is also a good idea. If the problem persists, you’ll need to contact a pest control company.

Bed bugs

Battling bed bugs is nowhere near as simple. While you could tackle the problem with a vacuum, steam cleaner, and a variety of chemical insecticides on your own, that’s not the safest—or most effective—route. Bed bugs can hide in spaces as small as the thickness of a credit card when they’re not feeding, and even foggers and bug bombs can’t typically penetrate these hiding places. If you have a bed bug problem, you may need to call a professional pest control company.

While most licensed pest control companies are prepared to treat both flea and bed bug infestations, we recommend calling Terminix or Orkin for conquering your pest issues.


Terminix’s customized bed bug treatments start with an extensive inspection of your house. A technician will remove visible bed bugs and use treatments to eradicate hidden bugs and eggs. The bed bug control is backed by the Bed Bug Guarantee. If any bed bugs are found in the treated room or areas within the next 30 days, the technician will come back for more treatments at no extra cost. If you buy mattress encasements for all mattresses and box springs in your home, Terminix will extend the guarantee to 90 days.

You can reach Terminix at 866-569-4035, or at this form.


The Orkin bed bug treatment involves its Assess, Implement, Monitor system, including conventional treatments with pesticides and heat treatments. Whole-room heat treatments require specially designed equipment that raises your home’s temperature high enough and for long enough to kill bed bugs.

If you’d like a free quote from Orkin, call 877-868-1416 or fill out this simple form.

FAQ about Fleas vs. Bed Bugs

How do I know if I have fleas or bed bugs?

Fleas have long, narrow bodies and leap from place to place. Bed bugs have flat, oval-shaped bodies and crawl. Fleas are also more likely to be found on animals and bed bugs are found on mattresses and furniture.

Do fleas bite humans in bed?

Bed bugs are more likely to bite humans while they sleep, but if you sleep with your pet on your bed, fleas may bite you there.

How can I tell the difference between a flea bite and a bed bug bite?

Flea bites are likely to occur on your feet and legs, and bed bug bites are likely to occur on your face, chest, and arms. However, the best way to tell is to check your pets for fleas and your mattress for bed bug and their excrement.

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