June 6, 2000 -- Experts have long speculated that children, and possibly adults, with allergies and asthma get more colds than other people. But new research suggests that instead, allergies might actually help to lessen colds' severity and duration.
Surprised? So were the researchers, who say the findings of their small study were the opposite of what they expected to find. The study's results were published in the Journal of Allergy and Clinical Immunology.
The findings are important because understanding why some cold sufferers have many symptoms while others have just one or two may someday help scientists develop vaccines to protect against the common cold.
"These findings suggest that [allergies] may not predispose people to more severe colds," study author Pedro C. Avila, MD, tells WebMD. "What we found was just the opposite of what we had thought." Avila is an assistant clinical professor in the department of medicine at the University of California-San Francisco's Cardiovascular Research Institute.
For the study, the researchers injected 20 allergy patients with rhinovirus infection, also known as the common cold. Then they divided the patients into two groups, and injected one group with substances known to cause allergic reactions, such as pollen. This group actually stayed well longer, and, when they did develop cold symptoms, their colds didn't last as long as those of the other group.
The researchers believe that the results show that multiple allergens within the nose do not worsen cold symptoms. Instead, they say, allergies may significantly shorten the duration of cold symptoms, and those symptoms might be milder.
"Allergens, per se, may not be what makes the cold worse -- maybe some people just get more severe colds," James F. Gern, MD, associate professor of pediatrics at the University of Wisconsin Hospital in Madison, tells WebMD.
Gern was not involved in this study, but has performed similar studies with different results. No one has undertaken a study like this one before, he says, and the findings may shed light on several aspects of the common cold.
Future studies will be important to confirm these findings, and researchers are now focusing on why people get colds, why some people get worse symptoms, and why some people never get sick, Gern says. "We see huge differences in how severe colds are. This study represents a good step forward in understanding what happens during a cold," he adds.
Avila plans future research to learn more about cold symptoms and their severity.
- In a finding that surprised researchers, exposing people with allergies to both the common cold virus and to allergens resulted in a shorter, milder cold, compared to those who were exposed only to the cold virus.
- Allergies do not predispose people to more severe colds and may actually lessen them, but scientists cannot yet explain this finding.
- More studies are needed to determine why people get colds and why some people have more severe colds.