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By Alex Bussey
Edited by Mike Martin
Reviewed by the Your.MD medical team
Fleas are small and hard to see, but their bites are difficult to miss.
They usually appear as red and very itchy bumps, and are normally found in small clusters on your lower legs. They can also appear on your arms if you’ve been petting an animal which has fleas.
Flea bites normally clear up on their own, but they can get infected if you scratch at them. This can lead to increased redness, pain and swelling around the bite.
Fleas in some parts of the world also carry diseases like typhus or bubonic plague. These conditions are rare in countries like the USA or UK, but they are more common in parts of Asia, Africa and the Americas, and can be very dangerous if they’re not treated properly.
If a bite becomes worse over time, infected, or if you feel unwell or have an allergic reaction you should see a doctor. Signs of infection include:
If the skin around the bite becomes infected you may need a course of antibiotics.
Fleas are parasitic insects that feed by sucking the blood of humans and animals. They often live on animals like cats, dogs or rats, but they will still feed on people if they can.
Fleas can also live for several weeks or months in carpets, soft furnishings, animal bedding or soil. They do this by creating protective cocoons, and lying dormant (inactive) until they sense that a potential host is nearby.
You’re more likely to be bitten by a flea if you:
Flea bites normally leave small, red lumps on your skin. These lumps can be extremely itchy or painful, and you may be able to see a small hole or puncture mark (called a punctum) in the middle of the bite.
Flea bites can also appear in clusters or lines.
It can be quite hard to tell the difference between a flea bite and the bite from another insect, such as a bed bug or a mosquito. If you’re worried and you want to know what’s bitten you, ask a doctor to take a look at your bite.
A doctor will be able to help you work out whether you’ve been bitten by a flea, and they’ll also be able to check for signs of infection.
Some people are hypersensitive (extremely sensitive) to some of the chemicals found in flea saliva. This makes the bites swell up after a few minutes and form an itchy blister or hive that lasts for several days or weeks.
These blisters may ooze or form a crust when they are scratched, known as papular urticaria.
Papular urticaria is normally harmless and self-limiting, which means that it will go away on its own. But the condition can be very irritating, so if you’re struggling with a swollen bite, it may be worth talking to a doctor or a pharmacist about taking an antihistamine to reduce some of your symptoms.
Flea bites on humans normally appear on the lower leg — often around your ankles or feet. This may be because fleas are most likely to jump up onto your body from the ground or from an infected animal.
It’s also common to find flea bites on your waist, and you may notice some bites on your forearms if you’ve been stroking or carrying an animal that has fleas.
Flea bites are normally harmless, and most will fade in a matter of days.
However, flea bites can get infected if you scratch them. This is because scratching can irritate your skin, and push harmful bacteria into any open sores.
Infected bites may become painful, red and pus-filled, with signs of oozing or crusting around the original site of the bite. Infected bites should always be examined by a doctor, and you may need to take a course of antibiotics to help your body deal with the infection.
Plague is also a serious bacterial infection that’s caused by the bacteria. It has many different forms, but bubonic plague is the most common. This causes symptoms of fever, chills, nausea and vomiting. It also infects your lymph nodes, causing characteristic swellings called buboes.
Diseases like typhus and bubonic plague are more common in some parts of Africa, North and South America and Asia.
You can treat a flea bite by washing the surrounding area with an antibacterial soap to prevent infection.
Talk to a doctor or pharmacist about using a calamine lotion or an anaesthetic cream if your bite is itchy, but try to resist the urge to scratch. Scratching flea bites can increase the chances of an infection.
If your bite swells up, try applying an ice pack to the affected area, or talk to a pharmacist or doctor about using an antihistamine to relieve your symptoms.
You should see a doctor if your symptoms get worse, or you see any pus leaking from your bites. This could be a sign that your bite has become infected.
The best way to prevent flea bites is to stop fleas from infesting your home. To do this you can take the following steps.
All cats and dogs should be treated regularly for fleas by a vet. This is the best way of preventing an outbreak in the home.
Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.