Around here it is said that if chiggers weighed a pound you'd have to carry a shotgun to go out in the yard. I have been terribly allergic to them since I got about 40 bites at the same time over 30 years ago. I use insect repellant if i'm going off the sidewalk around here.
Like has been said if they aren't already gone the first time you scratch it kills them. Basically the chigger spit they use to digest your skin is what causes the reaction. Hydrocortisone to relieve itching is about he best you can do. If allergic to that then some other anti-itch is about it.
