Yeahhh, i get the same thing. I get really bad reactions to bug bites aswell they swell up and dont go away for weeks. You could try a really strong repelent, or after being biten apply cream (for insect bites) and take some antihistomean. While i was on camp this lady who new about environment and stuff showed me this plants sap which can help with insect bites
This is extremely old now, so you probably won't even see this, but I would guess that your wife is allergic to chiggers. I have the exact same reaction to chigger bites. The most effective thing I have found is to get them off as soon as possible: the longer they have to feed, the worse my reaction is to them. They aren't hard to get off, just wash with soap and water or even a damp cloth. I use baby wipes since I have them around right now. Every time I step on any kind of grass when it is above freezing, I go in and wipe down as soon as possible. As far as after-bite treatment, I wouldn't get your hopes up. I am usually still itchy months later, and then the scars from the worse bites are still around months or even years later :( Just dab some antibiotic cream on it to prevent secondary infection, cry a little, and wait it out. Hope this helps someone, even if the original poster doesn't see it.