Thanks for all of the great information. I've printed out all of the responses for her and she is definitely interested in pursuing the ideas I've gotten. She's back today, headache gone, but after talking to her, I think she is going back to her doctor to get tested for allergies. She said they asked her if she had any food allergies, and she replied that she didn't know. Nothing else was done about it, so I suggested she go back and insist she be tested.
Anyway, thanks for all of the input.
Claudia
2009 Trek 7.6fx
2013 Jamis Satellite
2014 Terry Burlington