Intensity of itching due to mosquito bites

Mosquito bites are itchy bumps that form on the skin after the blood is sucked out by these invertebrates. The reaction the body has to this bite depends on the sensitivity a person shows, which depends, among other factors, on individual genetics.

Mosquito bites are endured by virtually all populations in the world. There are hundreds of different mosquito varieties, but not all are hematophagous. The main families of mosquitoes capable of biting humans are the Culicidae and the Psychodidae. In these, the females, which are the ones that bite, have a proboscis in their mouth that serves to pierce the skin and suck the blood. In this process, they can inject an anticoagulant which, together with saliva, is responsible for the skin reaction. These females need the protein supply from the blood in order to initiate egg laying.

Although desensitization and consequent minimization of the reaction usually occurs with the passage of time and exposure to the stings, the response to the sting occurs in two phases: the immediate reaction, characterized by the presence of an itchy inflamed bump, and the delayed, highly variable reaction that can range from mild itching to a more severe reaction.

Although the pathophysiology of the reaction to the bite is not entirely clear, it is thought to be the result of a combination of histamine contained in mosquito saliva, IgE-mediated reaction and an IgE-independent inflammatory response. The histamine found in saliva causes itching by binding directly to receptors on nerve endings, and local vasodilatation, causing the formation of wheals. In addition, in response to the bite, mast cells release endogenous IgE-mediated histamine, exacerbating the reaction. In addition to the above, IgG levels in response to the mosquito have been shown to increase in both immediate and delayed reactions.

Who do mosquitoes bite? Females, which are capable of biting, are specialized in detecting certain chemical traits that bring them closer to their target. The main factor that attracts them is the CO2 that people give off from breathing, and they can detect it up to 60 meters away. Other factors that attract them are the blood group, showing preference for people of group 0, certain body odors, use of floral colognes or, there are even studies that indicate that people who consume beer are more prone to these stings.