It is advisable to wear a mask when going outdoors for those who suffer from seasonal allergies.Photo provided to China Daily

Song has no idea when he developed hay fever.

He used to catch a cold during seasonal changes, or what he thought was a cold when he had a stuffy and itchy nose. In most cases, he would buy medication over the counter.

He eventually went to a hospital this spring, when his stuffy nose and headaches lasted more than a month.

To his surprise, the diagnosis was hay fever.

He now takes anti-allergic medication and wears a mask wherever he goes, and feels much better.

"Hay fever is a common condition, but its symptoms are very disruptive to patients' daily lives," Zhu says.

"Moreover, it is not curable. Once people get it, it's often a lifelong condition. Only few patients, mostly kids, will recover."

The condition is related to genes and disordered immunity, but the mechanism of hay fever is not clear. Therefore, avoiding allergens and symptomatic treatment - treatment that only affects a disease's symptoms, not its cause - are very important to protect patients from suffering, Zhu adds.

Although substances that cause allergic rhinitis vary from person to person, pollen, dust mites, animal dander and indoor mold are the most common triggers.

Allergy specialists are very busy in spring and autumn, because the symptoms peak during these months, when pollen and plant seed levels are at their highest.

For most people, medication and desensitization therapy are the best ways to control the disease's development, if not to cure it. Taking no treatment at all can be risky, experts warn.

"Many people think hay fever is not a big deal, and will fade away as spring or autumn are gone," says Zhang. "But this is very wrong."

Seasonal hay fever can evolve into perennial rhinitis that can affect people throughout the year.

Among all the allergy-related conditions, hay fever is one of the most persistent and harmful - it can increase the risk of many other diseases, such as asthma and glue ear, a condition in which the middle ear fills with fluid, Zhang adds.

Severe asthma is life-threatening, and glue ear can cause permanent hearing loss.

Many patients don't believe they've got hay fever when they are diagnosed. Quite a few treat themselves as if they have a cold, and drugs for colds are very harmful to such patients, according to Zhu.