FRIDAY, Nov. 8, 2013 (HealthDay News) -- The number of people with asthma who are allergic to cats is on the rise -- it's doubled over 18 years, a new study finds.
"From 1976 to 1994, positive allergy skin tests in people with asthma have increased significantly," study author Dr. Leonard Bielory said in a news release from the American College of Allergy, Asthma and Immunology (ACAAI).
"Not only have we found the number of asthma sufferers allergic to cats has more than doubled, but those with asthma are also 32 percent more likely to be allergic to cats than those without asthma," he added.
The researchers also found that people with asthma are more likely to be allergic to several environmental triggers common in the fall, including ragweed, ryegrass and fungus.
The study was scheduled for presentation Friday at the ACAAI's annual meeting, in Baltimore. The data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.
About 60 percent to 85 percent of people with asthma have at least one allergy, but the most common types of allergies in people with asthma have not been well researched, according to the ACAAI.
"This study helps us better understand common trends in allergy and asthma, which can lead to improved diagnosis and treatment," Dr. James Sublett, chair of the ACAAI indoor environment committee, said in the news release. "While it is unknown exactly why there has been an increase in asthma and allergy sufferers, it is thought a number of environmental factors can be responsible."
During the holidays, allergy symptoms can suddenly appear in people with asthma and those who've never had allergies. For example, while visiting friends and relatives with cats, a person may develop a runny nose, sneezing and itchy eyes.
There is also something called the Thanksgiving Effect, where college students return home and discover that they are now allergic to a pet that never before triggered symptoms.
"Allergies can strike at any age in life, with symptoms disappearing and resurfacing years later," Bielory said. "Allergies and asthma are serious diseases. Misdiagnoses and inappropriate treatment can be dangerous."
The U.S. Environmental Protection Agency has more about pets and asthma.