This spring's allergy season in New Jersey has been classified as "normal" because elevated levels of pollen began to show up as soon as the spring season officially began in March, but many Garden State residents report having the worst allergic symptoms they can recall.

(Andreas Rentz, Getty Images)

So what's going on here?

Leonard Bielory, a professor at the Rutgers University Center for Environmental Prediction and a leading authority on allergies, isn't surprised. He said recent studies confirm pollen levels are rising, and individuals who have been sensitized to one type of pollen begin to have allergic reactions to other types as well.

"People have been having increasing symptoms because they have a lower threshold because they're getting into more items, and they need less pollen to have a similar reaction," Bielory said.

He also said people are allergic to more types of allergens than in the past.

"There's been a doubling of pollens or allergens that people are allergic to over the past 25 years," he said. "The more you're exposed to an allergen, the more sensitive you become."

Bielory said high levels of oak and birch tree pollen are currently causing itchy eyes, runny noses and sneezing in many people.

"Oak and birch will last another two to three weeks and then we will see, in the beginning of June or the end of May, we'll start seeing more grass pollen," he said.

Bielory also predicted a very intense ragweed season later this summer. So what can you do to lessen allergic symptoms?

"There are helpful over-the-counter medications now available, including an inter-nasal steroid that's now being sold without a prescription that can lessen the inflammatory response associated with allergies that can trigger asthma," Bielory said.

He also said individuals should follow the pollen count "so you know what's out there, to better understand your symptoms."

He recommends downloading apps such as the ipollencount app for iPhones and iPads.