Flea Bites: Symptoms and Treatments

Fleas are a common parasite of cats and dogs, which means that pet owners will likely encounter these insects at least once. These tiny, hopping bugs feed on the blood of pets, causing itching, skin irritation, and possible infection. And humans aren’t safe either; although fleas prefer the blood of animals, they will also bite nearby humans occasionally.

But how can you recognize flea bites, what are the risks of being bitten by fleas, and what can you do to alleviate that maddening itch?

Why (and how) do fleas bite?

Fleas feed on the blood of mammals, which they get hold of by biting their hosts and draining their juice. They usually prefer the blood of animals but will also occasionally bite nearby humans.

Adult fleas have complex mouthparts, tools that are specially adapted for puncturing the skin and drinking blood.

Two saw-like structures, called the laciniae, are used to cut into to skin of their host. In the middle of these is the epipharynx, a needle-like projection that punctures the blood vessels beneath the skin. Once this is done, blood begins to flow to the food canal and into the flea’s gut. This process is helped by pumps in the flea’s mouth and gut, which provide the suction needed to draw the blood into the insect’s body.

Can flea bites be dangerous to us and our pets?

Most of the time, flea bites cause nothing more serious than an annoying itch. However, this doesn’t mean all bites are harmless, as fleas are well-known vectors for disease.

These tiny insects famously felled an estimated 60% of Europe’s population in the 14th century, due to their role in the spread of the Black Death. Although incidents of plague are rare nowadays, fleas can still infect you with typhus – and your pets aren’t safe, either!

The double-pored dog tapeworm (Dipylidium caninum) is a parasite that is harbored by fleas and can enter the stomach of your cat or dog if they swallow an infected insect. Animals with flea infestations will continually chew their skin and fur to cope with the itching, so this is easily done!

Although these tapeworms are mainly found in cats and dogs, they may also infect humans. The more fleas in your home, the more likely you are to accidentally swallow one, so keeping your pets flea-free is the best way to protect yourself and your family from unnecessary illnesses.

How often do fleas bite humans and pets?

To stay healthy and nourished, adult fleas must feed at least once every 12 hours, though they can survive an average of 2-4 days without blood.

Fleas will usually feed on pets, rather than humans. However, fleas will occasionally bite humans in their vicinity (usually when their preferred host, i.e. your cat or dog, isn’t around). Newly-hatched fleas are often found on carpets and soft furnishings and are most likely to bite humans. Baby fleas must feed within a few hours of emerging from their cocoons to avoid starvation. Beggars can’t be choosers, so these hungry young fleas will often make human blood their first meal if there isn’t a more suitable host nearby.

Why do fleas prefer the blood of your pets?

Although fleas will bite humans now and then, their blood of choice is always that of your cat or dog. This is good news for those tackling an infestation, but why exactly do fleas avoid drinking human blood?

The simple answer is that the biology of the flea is far better adapted for life on an animal host. When viewed under a microscope, the legs of fleas are covered in small, spiny, structures.

These are perfect for clambering through the dense fur of your pet, but not so well suited for clinging to your smooth and (mostly) hairless skin.

But, more importantly than this, fleas need pet blood to successfully reproduce. One study found that the cat flea, while able to survive and breed when fed only human blood, would produce three or four eggs per day; pitiful numbers, compared to their usual daily average of 20-30. Therefore, though fleas may bite nearby humans when they are particularly hungry, they will always prefer to feed on your pet.

What do flea bites look like?

On humans

Flea bites are pretty easy to spot on human skin. These small, itchy red bumps won’t swell up as much as mosquito bites do and are often found in groups or clusters. This is because fleas are often disturbed when feeding and will puncture the skin a few times before hopping off.

Be on the lookout for:

  • Groups of three or four bites in the same place.
  • Bites that look like small, red bumps, sometimes with a red ‘halo’ around them.
  • Bites on the ankles or lower legs.
woman scratching her arm


On pets

Flea bites can be tricky to see on pets, as their skin is usually obscured by fur. Nonetheless, it is easy to tell if your cat or dog has fleas from their behavior and other signs. You’ll know your pet could have fleas if:

  • They are scratching a lot or chewing at their fur.
  • You see fleas hopping around in their coat.
  • You see ‘flea dirt’ (small, black specs) in your pets’ fur, on their skin, or on their bedding.
dog scratching from fleas

Jessi et Nono/Shutterstock.com

Best treatment for flea bites on humans

Flea bites can be unbearably itchy, but scratching is a no-no! Once the skin over a bite is broken, an infection can easily set in. So, how can you take away the urge to scratch? Read on to find out what natural and over the counter treatments to use on flea bites.

Home remedies

Fortunately, flea bites are easy and inexpensive to treat at home. To soothe the itching, apply any of the following to affected areas a few times a day, or as often as needed.

  • Tea tree oil (remember: pure tea tree oil can irritate the skin. Dry diluting a few drops in water before applying the pure product to your bites).
  • Rubbing alcohol.
  • Aloe vera (this is often available as an ingredient in gels and lotions).
  • Ice (tip: avoid applying ice directly to the skin, as this can cause damage. Instead, wrap an ice pack in a towel and use this to soothe your bites).

Over the counter treatments

If you have lots of bites or the itching is severe, you may need to visit your pharmacist for an over the counter treatment. Scratching at mosquito bites can break the skin over them, which can lead to secondary infections.

Medicine for flea bites, such as anti-itch ointments and creams, can help to reduce itching and inflammation, giving the affected area time to heal properly.

Best treatment for flea bites on pets

Flea bites are trickier to spot on your cat or dog, but they’re just as itchy! If your pet has fleas, try the following flea removal and flea bite treatments.

Home remedies

De-flea-ing your pet can be a hands-on job but is necessary to clear your home of infestations. If you’d rather steer clear of chemical treatments, you can try the natural remedies below first:

  • Use a flea comb. Similar to a lice comb, a flea comb is used to manually remove bugs from your pet’s fur.
  • Spritz your pet with apple cider vinegar or white vinegar. Mix a 1:1 ratio of vinegar and water in a spray bottle, then spray your pet with it (taking care to avoid their eyes). Let the solution dry on their fur and repeat the process a few times a day to repel fleas and prevent more bites.

Over the counter treatments

  • Use a pet shampoo. Shampoos containing aloe vera, tea tree oil or oat proteins can help to soothe itching and reduce inflammation caused by flea bites. Some shampoos contain active ingredients (i.e. pesticides) that can effectively kill fleas and may be the most suitable option if you are battling an infestation.
  • Use a flea and tick prevention medication. These are products which you can apply to your pet’s fur to effectively repel fleas. This can help to prevent more fleas from biting your cat and dog and stop future infestations.


Flea bites are an itchy nightmare and one that can plague both you and your pets. Aside from being incredibly annoying, flea bites can also be a serious health hazard. These tiny parasites are known to harbor serious diseases (such as typhus, tapeworm and even plague) that can infect you and your animals. Flea bites can be soothed using a variety of home remedies and over the counter treatments, but the best way to deal with the bites is to get rid of the fleas!

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