It's allergy season and according to Prevention Magazine this year's allergy season is supposed to last longer than normal, staying with us through October. Unfortunately, for those with anxiety disorders, the allergy season can be even more difficult. Stress has been shown to worsen allergy symptoms.
Research on Stress and Allergies
A study conducted at Ohio State University in 2008 showed a definite link between stress and worsening allergy symptoms. Jan Kiecolt-Glaser and Ronald Glaser, professors at the university, recruited 28 men and women to participate in the study. All the participants had a history of allergies and hay fever.
Participants spent two half-days at the research center. They were given a battery of psychological tests to measure stress levels as well as skin pricks several times to measure allergic reactions. On one day, they were asked to give a 10 minute presentation to a panel and were also asked to solve math questions in their head. On the other day, they were asked to read magazines and other low-stress activities.
Researchers clearly saw that allergy symptoms increased or worsened during the stressful activities. There was a slight decrease in symptoms on the day of low-stress activities. The researchers also noted that on the day after the stressful situations, participants had higher levels of allergy symptoms, possibly because of prolonged effects of stress.
The results differed among participants with those who were considered "moderately" anxious having wheals (raised circles on the arms from the skin tests) that were 75 percent larger after the stressful activities. However, those who were "highly" anxious had wheals that were twice as large during the stressful day than the more relaxed day.
Late Phase Reactions
One of the results that most interested the researchers was the higher level of allergy reactions the day following the stressful activity. This is called "late phase reactions" and "suggests that sufferers may react strongly to other stimuli that hadn't caused them to develop an allergic reaction." 
These reactions may not react or improve, even with medications commonly used for allergies, such as antihistamines. According to Kiecolt-Glaser, "Antihistamines don't deal with those symptoms on the next day. People may be setting themselves up to have more persistent problems by being stressed and anxious when allergy attacks begin." 
We all know that managing stress is important for our overall well-being and our physical health. High levels of stress have been associated with physical illness and can lead to depression or anxiety. But for those who suffer from allergies, managing stress may help to lessen just how much you suffer during the spring and summer months, when pollen is high and allergies are at their worse.
The researchers in this study did not look at the effect of relaxation strategies on allergy reactions but it would follow that stress management and relaxation could not only lessen symptoms but make allergy attacks shorter.
"Allergies: Your 2013 Forecast," Date Unknown, Leah Zerbe, Prevention.com
"The Claim: Stress Can Make Allergies Worse," 209, Aug. 17, Anahad O'Connor, The New York Times
"How Stress and Anxiety Can Alter Immediate and Late Phase Skin Test Responses in Allergic Rhinits," 2009, June, Psychoneuroendocrinology
  "Stress, Anxiety Can Make Allergy Attacks Even More Miserable and Last Longer," 2008, Janice Kiecolt-Glaser, The Ohio State University Research News