From USA Today 3/16/2008
Your nose is not the only thing affected by allergies anymore. According to many studies, allergies also affect your moods. There was a study done that saw an association of positive moods and ragweed seasons. They followed patients who were allergic to ragweed for one year. During ragweed seasons, those with allergies became more depressed. In contrast, during the winter (when ragweed levels were down), their moods became more optimistic. A theory concludes that these mood changes are caused by the release of proteins by immune cells to protect against allergens that are present. The release of proteins (cytokines) discharges a chemical in the brain region that causes weakness, low moods, and a decrease in concentration.
Bonnie - I'd say this is a timely article given the nature of our recent Gut/Brain Connection piece. This is another reason why for those with allergies and intolerances must be extra vigilant in avoiding cross-reactors during the height of the allergy season.