What is is causing this allergic reaction?

• My fiance breaks out in a rash/hives whenever when spend time outside in the spring and summer. What could be causing it and what can we do about it? It seems like an allergic reaction to a bug bite, but we're not 100% sure it's a bug. It only happens outdoors and it manifests as small raised white spots surrounded by red irritation that start small but spread out to about a centimeter. It starts with just a spot or two but over time turns into several. When it happens I don't notice any bugs or get bitten by anything. It also seems to vary with location, she got just couple after watching a whole movie in a blanket on the grass but got at least a dozen in the 15 minutes we spent on a backyard patio this evening. She's taken a regional (Texas) allergy blood test that only showed a mild mold allergy. What could be causing this? Invisible bugs? Floating mold spores? Should she get abb allergy patch/prick test to identify it? And what should we do to prevent it? A dose of Benadryl and topical benadryl gel help a little with the itching, but the spots still linger for hours. Here are some photos so you can see how they showed up on her arms and legs tonight: http://imgur.com/8s9a6Vg http://imgur.com/b7TlUun

• Answer:

  Not a doctor ... But those honestly look like mosquito bites. Some people have very bad reactions to them. A coworker would get golfball size welts. In addition sometimes mosquitoes are attracted to some people than others.