New research shows that even slight stress and anxiety can greatly worsen a person's allergic reaction to some routine allergens.
Moreover, the added impact of stress and anxiety seem to linger, causing the second day of a stressed person's allergy attack to be much worse.
In a report that has been presented on August 14, 2008 at the annual meeting of the American Psychological Association in Boston, Ohio State University researchers described recent experiments meant to gauge how psychological stress might affect allergy sufferers.
"A huge number of people suffer from allergies and, while hay fever, for example, is generally not life-threatening, allergy sufferers often also have asthma which can be deadly," Kiecolt-Glaser added.
Some data suggest that 38 percent of the people who suffer from allergic rhinitis also have asthma, and that 78 percent of asthma sufferers have allergic rhinitis.
Kiecolt-Glaser and Ronald Glaser, professor of molecular virology, immunology and medical genetics at Ohio State, recruited 28 men and women. All of the volunteers had a history of hay fever and seasonal allergies.
The volunteers spent two half-days in a research unit at the Ohio State University Medical Center.
Each time, they were given the standard skin prick test several times to determine their reactions to various allergens, and blood, saliva and serum samples were taken before, after and at several times during the research project.
All of the participants were given a battery of psychological questionnaires to determine their levels of stress, anxiety, self-confidence and feelings of control over situations.
On the day that individuals were assigned to the low-stress control condition, they were given the skin prick test and then asked to read from a magazine. Then they were asked to tape themselves reading the same material aloud.
During the day that people were assigned to the experimental condition, however, they had a much tougher time.
Kiecolt-Glaser said: "People who were highly anxious had raised wheals that were twice as big after they were stressed compared to their response when they were not stressed. These same people were four times more likely to have a stronger reaction to the skin test one day later after the stress.
"We used a 'speech stressor test' used in a lot of psychology research. Basically the participants each appeared before a panel of several 'evaluators' who supposedly were behavioral experts. Participants had to give a 10-minute speech, which was videotaped, and then are asked a series of math questions they had to solve without paper or pen."
Afterwards, they had to watch their videotaped performance.
"The whole exercise is a nice stress experiment in the laboratory," she said.
The researchers measured the raised "wheals" that formed on the arms of the participants before and after they were stressed, as well as the next day.
"The wheals on a person who was moderately anxious because of the experiment were 75 percent larger after the experiment, compared to that same person's response on the day when they were not stressed," Kiecolt-Glaser said, signifying a stronger reaction.
"But people who were highly anxious had wheals that were twice as big after they were stressed compared to their response when they were not stressed. Moreover, these same people were four times more likely to have a stronger reaction to the skin test one day later after the stress," she said.
This next-day change - labeled a "late-phase reaction" - is important because it signals an ongoing and strengthening response to the allergens, and even suggests that sufferers may react strongly to other stimuli that previously hadn't caused them to develop an allergic reaction.