Mosquitoes, while pricking their prey, enter an anticoagulant substance that allows them to suck blood more easily. If they did not inject it, after the penetration of the sting, they would not be able to secure a good blood meal.
It is precisely this anticoagulant substance, together with the insect's saliva, which causes discomfort and irritation. As a rule, itching occurs immediately and lasts about half an hour, so a small bubble develops which tends to disappear after a short time.
In some hypersensitive people, instead, the mosquito bite induces an allergic response . This overreaction of the immune system is evident due to the immediate appearance of the wheal, with erythema and, sometimes, lymphedema (swelling due to lymph accumulation). In some cases, hard and papules are formed that can persist even for a few days.
