My intro-biology prof explained that allergies are when your body (incorrectly) assumes foreign matter to be a threat to your health, and attacks it as if you were sick. She further pointed out that people who suffer from allergies are far, far less likely to get gut worms. Likewise, people who have the greatest incidence of hook-worms are the least likely to suffer from allergies.

http://www.news-medical.net/?id=21178

This probably doesn't lessen your distress, however.