Bike shorts causing hives on legs - suggestions?

my friends legs break out (into hives?) every time she wears bike shorts. she’s tried several different brands of shorts and using body glide. any suggestions? photo:

http://i1034.photobucket.com/albums/a423/415brian/271880_2261178255177_1420074589_32555244_825828_o.jpg

She’s allergic to part of the fabric.

Can she get allergy tested?

I wonder if it is the shorts as she seems to have the redness not where the shorts are but below them…heat rash, blood flow,?
Is it only on her legs?
Does she get it with othe garments of the same materials?

I seriously doubt that it is the shorts… with that being said, I experienced the exact same thing this summer. First I thought I had chiggers, then I was sure it was poison ivy. A trip to the Urgent Care for some steroids helped but it came back once I was done with the drugs. Went to the ER the following week because it had gotten so bad and my legs became so painfully swollen. The ER doc kept saying that it looked like an “ingestion reaction” versus “contact” and questioned whether I was taking any diet pills or crazy supplements. I answered no, but he kept asking me about things I had consumed. I got kinda pissed after a while but I know that he was just trying to help. Got some more drugs which helped for a while but again, the hives came back. Only I noticed that it was only BELOW my bike shorts. So that got me thinking… what was I putting on my legs. Only two things… the same lotion I had been using for the past few years and a topical steriod cream. After googling the ingredients, I stumbled upon one of the side effects: phototoxic/photosensitive reaction between the drug and sunlight (and no the pharmacy did not tell me this nor provide me with a drug info sheet which could have saved me a lot of time and trouble).

So long story short, a dermatologist confirmed that it was a photo reaction and to stop using the steroid cream (obviously). I was given a pretty strong Prednisone taper (18 days worth too) which eventually cleared everything up. I would suggest heading to a dermatologist if you can. But it would also help to figure out if she is using any new lotions, creams, etc. first to see if she has recently introduced the offending irritant.