The negative side effects of stress on the human body are already common knowledge beginning with heart disease and ending with cervical cancer, but a new study revealed that stress might also worsen allergies.

It is not the first time stress is linked with allergies. In May, a group of researchers from Harvard Medical School present at the American Thoracic Society’s 2008 International Conference in Toronto revealed a study according to which mothers who were the most stressed during pregnancy were more likely to give birth to infants with higher levels of Immunoglobulin E or IgE, an immune system chemical linked to allergic responses.

For example, a mom having three or more negative events would have a 12 percent increased risk of having a baby with elevated cord blood IgE.

The new study was conducted by Jan Kiecolt-Glaser, a psychologist and psychiatry professor and stress researcher at Ohio State University and involved 28 volunteers with a history of hay fever and seasonal allergies.

The volunteers were subjected to a low-stress condition such as reading quietly from magazines and to much more stressful conditions such as giving a videotaped speech in front of a group of “behavior evaluators” and solving math problems without paper or pen in front of the group and then watching their videotaped performance.

Surprisingly, the researchers found that allergic reactions were much worse in people who were highly anxious (about 75 percent worse compared to the allergic reactions in people subjected to low-stress conditions) and that the worsening of allergies could linger after the stress had passed. The allergic reactions most common on the volunteers appeared on the forearm as slight wounds, or “wheals.”

“What’s interesting about this is that it shows that being stressed can cause a person’s allergies to worsen the next day. This is clinically important for patients since most of what we do to treat allergies is to take antihistamines to control the symptoms – runny nose, watery, itchy eyes, and congestion. Antihistamines don’t deal with those symptoms on the next day,” Dr. Kiecolt-Glaser said.

The problem is more serious than previously believed as people suffering from allergies often also have asthma, a condition that can be deadly under stress, she added.

The same thing was highly supported by co-investigator Gailen Marshall, a professor of medicine and pediatrics at the University of Mississippi.

“Late-phase reactions also occur in allergic asthma and can, in the proper settings, be potentially life-threatening. The results of this study should alert practitioners and patients alike to the adverse effects of stress on allergic reactions in the nose, chest, skin and other organs that may seemingly resolve within a few minutes to hours after starting, but may reappear the next day, when least expected,” Marshall said.

The findings were presented at the 116th annual convention of the American Psychological Association in Boston.