SEATTLE – Allergy sufferers know the drill: Eyes that itch and water; sneezes that won't stop; the fear that a hidden morsel of peanut will trigger a life-or-death crisis. Over-the-counter drugs and allergy shots deliver relief to some people, but not others.

Now, a discovery by Seattle researchers holds out the hope of better diagnosis and treatment for allergies of all types — and may even lead to a cure someday.

"I think it's a big deal," said Dr. David Robinson, an allergy specialist at Virginia Mason Medical Center and co-author of the study in the journal Science Translational Medicine. "Ultimately we're interested in fixing allergies and treating people, but you have to understand it first."

Led by researchers at Virginia Mason's Benaroya Research Institute, the Seattle team is the first to find a way to distinguish the "bad" immune-system cells that trigger allergies from "good" immune cells that fight infection. They also showed that effective allergy therapy banishes the bad cells from the body.

"If you are allergic, you have those bad cells," said lead author Erik Wambre. " If you are not allergic, you don't."

That means scientists should be able to develop a test to identify people at risk of allergies, even at a very young age, he said. For parents, that could eliminate the panicked trips to the emergency room that are often the first indication that their child has a dangerous food allergy.

Researchers at the Benaroya Research Institute discovered that “if you are allergic, you have those bad cells.”

But it's the possibility of stamping out the bad cells altogether that has the researchers most excited. "My hope is that we might find a drug that will specifically destroy the [bad] cells, or at least stop them," Wambre said

Almost 50 million Americans suffer from nasal allergies, while about 4 million children have food allergies. The Asthma and Allergy Foundation of America estimates the total amount spent on drugs, shots and other health care at nearly $18 billion a year.

Allergic reactions are triggered when the immune system mistakenly sounds the alarm over harmless substances like pollen or dust or cat dander.

Identifying the cells responsible has been tough because there are so few of them, Wambre said. A milliliter sample of blood can contain more than a million white blood cells, but only a handful fall into the "bad" category.

Working with blood from patients with and without allergies, the researchers screened each sample for 200 proteins or other characteristics. It took them seven years to zero in on five key differences between good and bad cells, Wambre said.

"The potential may be there for turning off the allergic process," Robinson said. "Honestly, we're not sure how far this is going to go at this point."