While summer is by far my favorite season, fall is a close second. The moderate temperatures and decreased humidity means I can spend more time outside doing things I love: hiking, walking and spending time at the lake. But that time in nature is promptly spoiled when I find myself covered in red, itchy lumps after spending just a few minutes outdoors. Because even though fall is almost here, pesky mosquitos are still active until early November. 

If you’re like me, you get frustrated by the number of mosquito bites that appear all over your body, making you feel like scratching the skin around the bite until you reach bone. While the bites alone can be annoying, it’s just downright infuriating when I come inside sporting several new bright-red welts while my friends so kindly report how they don’t have a single one. 

Why is that? It’s not that we’re particularly unlucky. There are actually scientific reasons why mosquitoes single out certain people. Here’s exactly why mosquitoes bite, and how you can make yourself less of a target this season and beyond. (You can also find out how to easily remove ticks 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 bite, and they do so to receive proteins from your blood needed to develop their eggs. 

Why are some people more prone to bites?

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

Blood type

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

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

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

Clothing color 

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

Carbon dioxide

Mosquitoes use sight and smell to find hosts to bite. One of the quickest ways mosquitoes can sniff out 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 for carbon dioxide detection and can sense it from 164 feet away. 

Because carbon dioxide is a huge attractor, people who emit more of it — larger individuals and people who are breathing heavily when working out — 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 people 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 attractive to mosquitoes, but they do know that genetics, bacteria on the skin and exercise all play a factor. Genetics impact the amount of uric acid emitted, while exercise increases lactic acid buildup. 

Beer

In a small study, mosquitoes were observed to land on participants more frequently after they had drunk a small amount of beer. But before you swear off beer for good, know that the study only had 14 participants, and it found that mosquitoes may only be marginally more attracted to people who have been drinking beer.

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

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

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

Our body responds by releasing histamine — a chemical that is released by white blood cells when your immune system is fighting against allergens — which causes the itchiness and inflammation of the bite. 

Prevention and treatment of mosquito bites

The best way to handle a mosquito bite is to not get them in the first place — but often times, 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 that contain DEET)
• Use natural repellants (citronella essential oil, neem oil, thyme essential oil)
• Avoid going outside at dawn or dusk 
• Avoid dark-colored clothing, specifically black
• Avoid standing water and try to eliminate standing water near your home
• Use mosquito netting when camping or sleeping outdoors

Mosquito bites, while annoying, are often not severe and will resolve in a few days. In the meantime, there are several treatments to alleviate the itchiness and inflammation:

• Clean with rubbing alcohol if 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

Though difficult, try as best you can to not itch the bite too roughly to prevent any sort of skin reaction or infection. 

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

The information contained 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 health provider regarding any questions you may have about a medical condition or health objectives.