An insect bite on the ankle causing swelling can be a result of a combination of several factors. Swelling tends to be “bigger than usual” when the body’s immune system is compromised by prescription medications, and when there already is edema in the ankle and the insect bite on the ankle is “enlarged” by the existing edema. The toxin of the insect bite is dispersed by the edema and the ankle swells up even more.
In Texas, a bite on the foot or the ankle by a fire ant will swell and hurt, not itch. Texas fire ants are big insects and their bite is vicious, toxic and painful.
There are several types of mosquitoes in the southern United States. The most often seen are the small brown mosquitoes and the larger black mosquitoes. In the Tropics, there are mosquitoes that are large with a black or brown head and a large wingspan and a tail stem that has black and white colored “rings” on it, like the black and white colored rings on one of the species of venomous snake.
The bite by one of the mosquitoes with the black and white “rings” on the tail stem is very nasty and a large boill-like swelling will rise almost immediately.