My toddler has 3 fire ant bites on his foot. 2 are swollen. is this normal?

Allergic reaction: Very common in response to ant bites. The question is- if this swelling is due to allergic reaction or infection/ cellulitis. This can only be judged through actual visualization of the swelling by md.

Probably: Fire ants sting & inject solenopsin - an alkaloid venom. This causes a welt which can become fairly swollen. Within hours to a day a sterile pustule usually forms. If the whole foot is swollen this could represent an allergic reaction. What you are describing may be a fairly normal fire ant sting reaction. When in doubt see a physician for evaluation.