5 unexpected reasons why you get so many mosquito bites: blood type, clothing and more

While summer is by far my favorite season, fall is a close second. The moderate temperatures and reduced humidity allow me to spend more time outside doing things I enjoy: hiking, walking and spending time by the lake. But that time in nature is quickly spoiled when I find myself covered in red, itchy bumps after being outside for just a few minutes. Because although it is almost autumn, annoying mosquitoes are still active until the beginning of November.

If you’re anything like me, you get frustrated with the number of mosquito bites that appear all over your body, making you feel like you’re scratching the skin around the bite until you reach bone. While the bites alone can be annoying, it’s downright irritating when I come in with several new bright red welts while my friends are kind enough to report that they don’t have any.

Why is that? It’s not that we’re particularly unlucky. There are actually scientific reasons why mosquitoes pick out certain people. This is exactly why mosquitoes bite and how to make yourself less of a target this season and beyond. (You can also find out how to remove draw easily without tweezers.)

Why do mosquitoes bite?

Contrary to what you might think, mosquitoes don’t bite people for food – they feed on plant nectar. Only female mosquitoes sting, and they do that to get proteins from your blood that are needed to develop their eggs.

Why are some people more prone to bites?

There are several factors that influence why some people are more prone to mosquito bites than others:

Blood type

A common belief is that mosquitoes are attracted to certain blood groups, since mosquitoes bite people for their blood. Blood type is determined by genetics, and each blood type is made from the different sets of specific proteins, called antigens, on the surface of red blood cells. There are four main blood groups: A, B, AB, and O.

While there are no firm conclusions about which blood type is more attractive to mosquitoes, several studies have suggested that people with type O are most palatable to mosquitoes. A 2019 study observed the feeding behavior of mosquitoes when presented with different blood type samples, and found that mosquitoes were fed the type O feeder more than any other. A 2004 study also found that mosquitoes land significantly more on blood group O secretors (83.3%) than group A secretors (46.5%).

However, these studies are not definitive and much is still up in the air about mosquitoes’ preferences when it comes to blood type.

Clothing color

Mosquitoes are very visual hunters when it comes to finding a human to bite. This means that movement and dark clothing colors such as black, navy and red can stand out to a mosquito. Research has shown that mosquitoes are more attracted to the color black, but little additional research has been done as to why this is the case.

carbon dioxide

Mosquitoes use sight and smell to find hosts to bite. One of the fastest ways mosquitoes can sniff a person is through the carbon dioxide emitted when we breathe. According to research published in the journal Chemical Senses, mosquitoes use an organ called a maxillary palp to detect carbon dioxide and can sense it from 50 meters away.

Because carbon dioxide has a huge pull, people who emit more of it — larger individuals and people who breathe heavily while exercising — are more attractive to a mosquito.

Body odor and sweat

Mosquitoes are attracted to more substances and compounds than just carbon dioxide. Mosquitoes can find humans to bite by smelling substances present on human skin and in sweat, including lactic acid, uric acid and ammonia.

Researchers are still learning why certain body odors are more appealing to mosquitoes, but they do know that genetics, bacteria on the skin, and exercise all play a factor. Genetics influence the amount of uric acid emitted, while exercise increases the build-up of lactic acid.


In a small study, mosquitoes were observed to land on participants more often after they drank a small amount of beer. But before you swear off beer for good, know that the study only had 14 participants, and mosquitoes may be only slightly more attracted to people who drink beer.

Belly of woman scratching hand against white background

The size and severity of a bite relates to how your immune system reacts to the saliva introduced by the mosquito when it bites.

Suriyawut Suriya/EyeEm/Getty Images

Why do some people swell more from mosquito bites than others?

Mosquito bites can range in size from small spots to large welts. Why is this the case?

Bites affect people differently. The size and severity of a bite relates to how your immune system reacts to the saliva introduced by the mosquito when it bites. When mosquitoes sting, they inject some saliva when drawing blood. This saliva contains certain anticoagulants and proteins, which cause the immune system to react to these foreign substances.

Our bodies respond by releasing histamine — a chemical released by white blood cells when your immune system fights against allergens — which causes the itchiness and inflammation of the bite.

Prevention and treatment of mosquito bites

The best way to deal with a mosquito bite is not to get them – but often that’s easier said than done.

Some common ways to prevent mosquito bites include:

  • Use repellents and bug sprays (Repel, Off! Deep Woods and other brands containing DEET)
  • Use natural repellents (citronella) essential oilneem oil, thyme essential oil)
  • Do not go out at sunrise or sunset
  • Avoid dark colored clothing, especially black
  • Avoid standing water and try to eliminate standing water near your home
  • Use a mosquito net when camping or sleeping outside
different kinds of bug spray lined up on a table

Repellents are very effective in preventing mosquito bites.

Amanda Capritto/CNET

Mosquito bites, while annoying, are often not serious and disappear within a few days. In the meantime, there are several treatments to relieve the itching and inflammation:

  • Clean with rubbing alcohol like a fresh bite
  • Take an oatmeal bath
  • Use over-the-counter antihistamines such as Benadryl or Claritin
  • Apply mild corticosteroid creams
  • Use aloe vera to reduce inflammation
  • Try a cold compress

Although it is difficult, try your best not to itch the bite too roughly to avoid any kind of skin reaction or infection.

For more information about the five clever ways to repel mosquitoes this summer, the mosquito prediction tool launched by Google and Off, and how you can make your own DIY traps for mosquitoes, hornets and other flying pests.

The information in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified healthcare professional if you have any questions about a medical condition or health goals.

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