The heat wave that scorched mainland Japan last summer means misery for seasonal allergy sufferers this spring.

The pollen volume in the air is expected to be up to 30 times higher than 2004 in some places and two to three times more than average, according to the Japan Weather Association.

“No question, the pollen counts are through the roof,” said Navy Lt. Ron Purcell, an internal medicine doctor at Yokosuka Naval Hospital near Tokyo.

A hot summer with strong sunlight helps flower buds grow and increases pollen dispersal the following spring, said the weather association’s Takashi Horiguichi. Also, pollen in the air tends to be high following a sparse pollen year, he said, adding that last year’s pollen dispersal was the lowest in 10 years.

Tree pollen typically causes spring allergies. Japanese cedar, Purcell said, “seems to really give people fits here.”

Cedar is about 20 percent of Japan’s forest. Cedar pollen started to disperse in the Kanto Plain in late February; though past their peak dispersal time, the trees will continue to pollinate through April, Horiguichi said. And cypress, already showering the Kanto region with pollen, is unlikely to let up until early May.

In northern Japan, cedar began discharging pollen in late March; cypress, since early April, Horiguichi said. Southern Japan’s tree pollen season is almost over. Grass and weed pollen, such as from Timothy and orchard grasses in summer and ragweed in fall, also can aggravate allergies. July and August pollen counts will depend on the weather, Horiguichi said; rain and cold reduce pollen.

Classic symptoms of seasonal allergies, commonly known as hay fever or allergic rhinitis, include itchy eyes, nose and sometimes back of the throat; sneezing; runny nose and a cough due to post-nasal drip, according to Japan health officials.

Someone who never had seasonal allergies in the States may wake up to itchy eyes and a stuffy nose in Japan because vegetation differs, health officials said.

But allergies usually take a year after exposure to kick in, Purcell said. “When your body gets exposed to these pollens and grasses and decides it doesn’t like it, it secretes a chemical that learns to recognize that pollen,” he said. “Next year, those cells in the mucous membranes ... are waiting for the pollen.”

In the ensuing chemical reaction, the body releases histamine, which causes itchiness, redness and other familiar symptoms, Purcell said.

Indoor allergens such as animal dander, indoor mold or cockroach or dust mite droppings also may cause hay fever-like symptoms, said Staff Sgt. Rebekah Virtue of Misawa Air Base’s 35th Medical Operation Squadron. Mild seasonal allergy symptoms can be treated with over-the-counter medication but a prescription steroid nasal spray probably is most effective, Purcell said, though it takes three to six weeks to really work.

“I tell people be aware if they have allergies and come in ... and start using the steroid a few months before allergy season starts.”

Reducing exposure to a known allergen also can work, Purcell said. “If it’s a bad allergy day, try to stay indoors,” he said. “It’s hard to avoid pollen. It’s everywhere.”

Hana Kusumoto contributed to this report.

Allergic reactions

Sources of common seasonal allergy-causing pollen in Japan include:

Spring: Cedar, cypress, birch, elm and alder trees.Summer: Timothy and orchard grasses.Fall: Ragweed, mudwort.— Source: Yokosuka Naval Base

Relief

Steps to help control or ease seasonal-allergy symptoms include:

Take over-the-counter or prescription medication.Avoid the outdoors on dry, windy days.Shower after being outside to rid hair and skin of pollen.Wear eye protection such as sunglasses to keep pollen out of eyes.Keep windows and doors shut.Use cold compresses, washcloths, ice packs or lubricating eye drops to relieve itchy eyes.Wear a face mask designed to filter pollen.— Source: U.S. Navy and Japan health officials