Stress and anxiety can make allergies worse. It can also mean the allergy – such as hay fever - lasts longer.
Researchers made the discovery when they tested 28 hay fever sufferers while they were subject to different stress levels.
Those who were relaxed showed no difference when their seasonal allergy was measured with a skin test, which displayed as a slight wound, or wheal, on the forearm.
The participants who were moderately stressed showed a 75 per cent increase in wheal size, but those who were highly stressed saw their wheal size double, and last into the next day.
(Source: Meeting of the American Psychological Association, Boston, August 14, 2008).