Why Do Mosquito Bites Itch?

A warm summer evening can be all but ruined by mosquito bites, resulting in itching for days afterward. Why do mosquito bites itch? Would you believe it’s because of allergies? Let’s start from the top. A female mosquito’s mouth consists of multiple tubes. While one tube is used to suck blood from the unfortunate victim, another is used to pump saliva into the person’s blood vessel. Mosquito saliva is an anticoagulant, meaning it prevents blood-clotting, allowing blood to travel smoothly and efficiently from person to mosquito. However, humans readily become allergic to some proteins in mosquito saliva, resulting in the itch. In allergic reactions, including those brought on by mosquito saliva, the human body releases histamine. Histamine dilates blood vessels to allow white blood cells, blood plasma proteins, and various immune system tools greater access to the site of the bite. While the release of histamine is part of our bodies’ fight against an allergen, it also causes the inflammation and itching for which mosquito bites are infamous. While on the lookout for their next bite, mosquitoes use their antennae and their palps, the organs between their antennae, to determine the person they will land on. The antennae and palps are used to detect carbon dioxide and odor, and a higher concentration of both increases the likelihood of your getting bit. For instance, when you’re working out and breathing out more carbon dioxide, you’re a more likely target than if you were standing still. Interestingly, red, orange, and black colors are also favored by mosquitos. So next time you’re relaxing outdoors in the summer, stick to a cooler color palette.