Mosquito bites and treatment

Visible, irritating bites are due to an immune response from the binding of IgG and IgE antibodies to antigens in the mosquito's saliva. Some of the sensitizing antigens are common to all mosquito species, whereas others are specific to certain species. 

There are both immediate hypersensitivity reactions (types I and III) and delayed hypersensitivity reactions (type IV) to mosquito bites.Both reactions result in itching, redness and swelling. Immediate reactions develop within a few minutes of the bite and last for a few hours. Delayed reactions take around a day to develop, and last for up to a week.

Several anti-itch medications are commercially available, including those taken orally, such as Benadryl, or topically applied antihistamines and, for more severe cases, corticosteroids. 

Using a brush to scratch the area surrounding the bite and running hot water (around 49 °C or 120 °F) over it can alleviate itching for several hours by reducing histamine-induced skin blood flow. 

Tea tree oil has been shown to be an effective anti-inflammatory, reducing itching

(Tea tree oil, or melaleuca oil, is a pale yellow colour to nearly colorless and clear essential oil with a fresh camphoraceous odor. It is taken from the leaves of the Melaleuca alternifolia, which is native to the northeast coast of New South Wales, Australia. Tea tree oil should not be confused with tea oil, the sweet seasoning and cooking oil from pressed seeds of the tea plant Camellia sinensis (beverage tea), or the tea oil plant Camellia oleifera.)