How is a mosquito bite most appropriately diagnosed?

A mosquito bite is most appropriately diagnosed as a wheal. This is because a wheal is a raised, itchy area of skin that occurs due to localized edema (swelling) and is often seen with allergic reactions or insect bites. The body responds to the mosquito's saliva by releasing histamines, leading to swelling and redness in the affected area, characteristic of a wheal.

The formation of wheals is a common reaction to insect bites, as they are typically round and can vary in size depending on the individual's sensitivity to the bite. This reaction is part of the body's inflammatory response, which aims to protect against perceived threats like allergens or pathogens introduced through the skin.

In contrast, a cyst is a closed sac filled with fluid or tissue, a bulla is a large blister filled with clear fluid, and plaques are raised areas of skin that can be thick and scaly. None of these terms accurately describe the typical response seen from a mosquito bite, highlighting why wheal is the most appropriate diagnosis in this context.