Yet pediatric allergies are so disruptive that three-quarters of affected children had taken medication for the condition in the previous month, their parents told interviewers.

Overall, the Pediatric Allergies in America report - based on a national opinion survey with funding from Sepracor, which makes allergy medicines - found widespread unhappiness with available treatments for children with allergies.

So it's not surprising that a key focus of the American Academy of Allergy, Asthma and Immunology's annual meeting, which brought 7,000 physicians, researchers and others to Philadelphia for five days ending tomorrow, is the search for new ways to tackle allergies.

Edward S. Schulman suffers from dust allergies. He really understands when patients complain about allergy medicines that don't work or make them too drowsy to use. In his laboratory, he is making progress.

Instead of using antihistamines to block respiratory allergies, Schulman and colleagues at Drexel University College of Medicine think they can shut down the specific gene in a type of tissue cells - so-called mast cells - that produce histamine, a chemical that triggers allergic reactions.

He currently is testing the technique on cultured cells in the laboratory. If the approach can be made to work in people it has the potential to transform the treatment of respiratory allergies.

"It is like a very clean surgical incision of one gene's product," says Schulman, director of the Allergy and Asthma Center at Hahnemann University Hospital.

That could still be years away.

Yesterday, Schulman's team presented its findings to the conference at the Convention Center.

New allergy therapies based on better understandings of immune mechanisms are a key focus of the meetings, says Arnold I. Levinson, chief of Allergy and Immunology at the University of Pennsylvania School of Medicine.

Those mechanisms are "a complex symphony of cells which, when they act in concert, give rise to allergic symptoms," Levinson says. "Everyone is looking for the major switches that are involved in turning on and off that symphony of players.

"If you knock out some of these key players the orchestra doesn't work so well," he says, and adds a prediction: "Five years from now allergy shots as we know them are going to be passé and will be replaced by these kinds of therapeutic responses."

On Friday, the opening day, the conference focused on eosinophilic esophagitis (EE), a newly recognized disease that can cause heartburn, ulcers and difficulty swallowing.

"Not only this disease, but all allergic diseases, are rising dramatically in the last 20 years, and we don't have the perfect answer for why that is happening," says Jonathan Spergel, an allergist at Children's Hospital of Philadelphia.

Perhaps we are exposed to different allergens today than in the past.

Among the reasons that cases of EE are on the rise is that doctors now know to look for it.

EE is a food allergy - but figuring out what specific allergens the patient is reacting to can be challenging, Spergel says. The traditional scratch tests don't always work.

At Children's Hospital, allergists focus not on treating the symptoms but on identifying foods that cause the reaction, and changing the patient's diet to avoid the allergens and the problem altogether.

"All the patients get better by treating with diet," Spergel says. Sometimes, however, the patient reacts to almost everything, and can be cured only with a liquid diet. In those extreme cases steroids can be used to reduce the symptoms.

Over the conference's five days, more than 1,000 abstracts were to be presented. Among them:

A study found that exposure to diesel exhaust particles doubled the risk of wheezing in young children.

A national survey suggested that exposure to mouse allergens, which were found in 82 percent of homes, significantly increased the chances of asthma attacks in people with the condition.

A Canadian study of 971 children with peanut allergies found that they were often exposed accidentally and that most moderate and severe reactions were managed inappropriately. The authors concluded that parents needed to be better educated on how to handle accidental exposures.

A study of mice with peanut allergies found that low-dose exposure during pregnancy and lactation prevents peanut-induced anaphylactic reactions in the offspring.