NEW YORK (Reuters Health) - Children with the allergic skin condition eczema are at increased risk of developing asthma well into adulthood, according to a decades-long study.
Australian researchers found that among nearly 8,600 study participants followed from the age of 7, those who'd had childhood eczema were roughly twice as likely to develop asthma by middle-age.
It's not clear whether the eczema directly contributed to asthma development in these cases. However, the findings do suggest a cause-and-effect relationship between the two conditions, according to the researchers, led by Dr. John A. Burgess of the University of Melbourne.
They report the results in the Journal of Allergy and Clinical Immunology.
The findings come from a study that began in 1968, when parents of 8,583 7-year-old children in Tasmania were surveyed about their children's health. The children also had a medical exam. At that time, 769 were found to have eczema.
The researchers found that children with eczema were twice as likely as their peers to develop asthma as teenagers, and 63 percent more likely to develop the lung condition as adults.
Other researchers have noted a phenomenon dubbed the "atopic march," which refers to the sequential development of eczema, followed by nasal allergies and finally asthma. The current findings, Burgess and his colleagues write, suggest that this march continues on well past childhood.
It's also possible that eczema directly contributes to asthma development, the researchers say. One theory is that certain immune system cells, primed for an allergic response, might migrate from an eczema patient's skin to tissue of the airways. That could make their airways more likely to inflame in response to an inhaled allergen, leading to asthma symptoms.
"Our data suggest that a causal link is possible," Burgess told Reuters Health.
"If in fact the link was causal," he added, "then aggressive treatment of childhood eczema aimed at really tight control of that disease might have an impact on the development of asthma in adolescence and in adult life."
SOURCE: Journal of Allergy and Clinical Immunology, August 2008.
