Steroids more effective than antihistamines when used as needed for allergies
November 25, 2001
Researchers from the University of Chicago have demonstrated that corticosteroid nasal sprays are more effective than antihistamines when used "as needed" for treatment of seasonal allergies. This finding, published in the November 26 issue of the Archives of Internal Medicine, suggests that the current guidelines and prescribing patterns, which favor the use of antihistamines as the first-line treatment for mild or moderate allergies, need to be revised.
One out of five people in the United States suffers from a seasonal allergy such as hay fever. Both corticosteroid sprays and antihistamines can prevent allergy symptoms such as sneezing, runny nose, congestion and watery eyes when used continuously. But very few patients take these medications continuously. Most take them sporadically, in response to symptoms.
"Changing the current guidelines to match patient practice would help more people and reduce health care costs," said Robert Naclerio, MD, chief of otolaryngology-head and neck surgery at the University of Chicago and director of the study.
Although antihistamines are prescribed three times as often as corticosteroids, "we found that intranasal corticosteroids are more effective than antihistamines when used as needed, which is how most patients take these medications," he added. "Plus, they cost less than the non-sedating antihistamines."
The researchers enrolled 88 patients with ragweed allergies in a four-week study during the 1999 hay fever season. The patients, 44 in each group, were matched for allergy severity. One group was told to take a standard dose -- two sprays in each nostril -- of the corticosteroid fluticasone (Flonase) whenever they felt symptoms. The other group was told to take one tablet of the non-sedating antihistamine, loratadine (Claritin).
Total symptoms were similar when the patients began the study. Significant differences began to emerge after five days, however, and they remained until the end of the study at 28 days.
The steroid nasal spray group reported far fewer symptoms such as sneezing, runny nose and congestion over the four weeks than the antihistamine group. Their scores on a quality-of-life survey -- which looked at the impact of allergies on factors such as sleep, emotions and daily activities -- also showed significantly fewer allergy-related problems.
In addition, the nasal spray group also had better scores for various biomarkers of an allergic reaction. They had fewer eosinophils -- a type of immune cell associated with allergies -- at two weeks and at four weeks, when the study ended. They also had lower levels of eosinophil cationic protein, another allergy marker.
"The findings fit perfectly with our growing understanding of the mechanisms of seasonal allergies," said Naclerio.
People with hay fever react within minutes to contact with ragweed pollen. They sneeze and their eyes itch and water. The biology of this early response includes histamine release.
This early response is followed in a few hours by the late response, an influx in the sinuses of immune cells such as eosinophils and an increase in nasal reactivity to the allergen, called "priming."
Antihistamines can block the actions of histamines if taken in advance but they have no impact on the late response. Intranasal steroids inhibit the late response and prevent priming.
"Antihistamines," explained Naclerio, "taken once symptoms have already appeared, arrive too late to block the early response and have little effect on the late response. Corticosteroids taken when symptoms begin can prevent the late response and inhibit priming, which makes the patient more sensitive to subsequent contacts."
"Our study," he added, "demonstrates the greater importance of the late response compared to the immediate response."
The authors emphasize that continuous medication use is more effective than sporadic use in response to symptoms but acknowledge that few patients comply with those instructions.
In light of their findings, they suggest revising the current guidelines so that "intranasal corticosteroids should become the first-line treatment for seasonal allergies. They should now be recommended for regular use in patients with severe disease," said Naclerio, "and for as-needed use in patients with mild disease."
This study was supported in part by grants from Glaxo Wellcome Inc., Research Triangle Park, NC, and from the National Institutes of Health, Bethesda, Md.
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