Stress can make allergic reactions worse and longer-lasting, according to a new study from the Ohio State University.

Researchers studied 28 men and women with hay fever. The volunteers went to a research center for two half-days.

They were given skin tests to check how allergic they were to various substances. They were also measured for stress levels with questions.

They were also given tasks. To simulate a low-stress situation, they read a magazine, then read a selection out loud into a recorder. To amp up stress, they were told to give a 10-minute speech in front of a panel and answer math questions without paper or pencil.

The marks from the scratch tests were 75 percent larger when the participants went through the speaking engagement and showed signs of moderate stress, researchers reported. Those who were highly anxious had wheals that were twice as big as when they were unstressed.

They were also four times more likely to still show an allergic reaction the next day.

The research was presented to the American Psychological Association.