I agree with the poster to find out if her school has changed the soap they use in the bathroom/what the kids use to wash their hands with before they eat lunch.
My daughter came home with red, blotchy, itchy hands last April 2012 where eventually the skin would peel off her fingers. She also complained that they were swollen, though to look at them one couldn't tell. It took a long time of investigating, but we discovered two things.
One, they had changed the soap at her school. I had her stop using it. The issue with her hands persisted, but not as severe. Then I asked her if she was using something else because the issue with how her hands looked/reacted looked very much like an issue of contact dermatitis. She said yes: scented hand sanitizer from Bed, Bath and Beyond. Those usually have alcohol, synthetic perfume smells, and other chemicals in them. I had her stop using that. Then she complained that she wanted something she could use to disinfect her hands before she ate lunch. So I bought her a natural product at Whole Foods. She had no issues with using that product. That took care of part of the issue. But the problem still persisted, even through the summer when she wasn't in school.
The other thing we discovered later that fall (end of Nov) was that a natural histimine that we buy from our Naturopath that she uses for her grass pollen allergy and for stuffiness has stinging nettle in it. Her father is horribly allergic to stinging nettle, and she was caught in some stinging nettles earlier this fall and broke out on her arm. Because she was taking a nutriceutical/homeopathic remedy where stinging nettles were a part of the ingredients, not only were the stinging nettle sores on her arms not healing but it was affecting her hands, since there already was an outbreak there. She had also gotten her ears pierced the end of Sept 2012; the allergic reaction to the stinging nettles forced her body to detox it through the open holes in her ears, therefore, her newly pierced ears wouldn't heal.
Once she quit taking the antihismine with the stinging nettles in it, her hands cleared up and we're finally to the point, I think, where her ear holes have also finally healed (we're going on 5 months of having the starters in. I just bought some titanium post earrings for her to use to help her ears finish their healing, just in case it has anything to do with an alloy allergy).
Just last week she came to me and showed me that her hands were all red, swollen, itchy, broke out, etc. I asked her what she'd used that she wasn't supposed to use; she said the BB&B hand sanitizer. I asked her if she was now aware that it was, indeed, the BB&B hand sanitizer that was helping to contribute to the problem. She said yes. Whether that means she'll throw away the sanitizer or not, I don't know (she's 13 years old; typical teenager, wanting to do what everyone else is doing, even if it causes issues or problems). In fact, I'll make her throw out all of her BB&B sanitizers, but that doesn't mean she won't borrow from one of her friends at some point. So we're back to slothering Virgin Coconut Oil on her hands before bed at night to help speed up the healing process.
Your daughter definitely has something that she is allergic to OR she was bit by a spider or some other insect that didn't agree with her. Defnitely need to do a thorough check of everything she eats, drinks, uses, etc. to see if you can figure out what it is that doesn't like her. With my daughter, it took about 7 months total to finally figure out all the pieces in the puzzle.
You also might be interested in seeing a Naturopathic doctor and having her thoroughly tested for everything, including food intolerances. Does your allergist use the Elisa/Alcat test? That is considered the gold standard when it comes to finding out what all the triggers are, both allergy and intolerance wise.
It took months to get my daughter's hands healed up and her newly pierced ears to heal--all because we discovered she was allergic to stinging nettles and to synthetic hand soap/sanitizer. We only use all-natural, organic hand soap and bath soap in the house, so it's not a stretch that she would develop a resistance against anything synthetic.
Try virgin coconut oil on her hands. Yes, it looks white and is solid in the jar, but the minute the oil hits the hands it turns liquid. Wonderful, wonderful stuff.
I myself have issues with hives. I get hives in two ways. One, if I eat anything made with real mint oil--peppermint, spearmint, creme de menth, etc. If I eat a piece of creme de menth cake, for example, I can actually tell when I've eaten enough cake and need to stop because I'll suddenly get a very warm and tingly feeling (so far, I can eat a small piece and remain hive free).
The second way I get hives is from the cold. I have something called cold urticara. If I go outside and shovel snow in the winter, I get hives. If I go outside and do any winter sport activities, I get hives. If I take a cold shower when it's very hot in the summer, I get hives. If I go to an outside water park and go on the rides when it isn't very warm outside, I'll get hives. Sometimes I'll even get hives in between my thighs when I ride a horse! All I can do about that is take an antihistimine to help take the hives away. This type of hives came at the same time I became allergic to mint oil, when I was 10 years old. So I've been battling this my whole life. And I live where it's cold--grew up in MN, live in WI.
Good luck. I hope you discover the cause.