In northern China, basically, after the National Day, the flowering period of grasses and trees is over, and the annoying hay fever is “well”, with nasal itching, paroxysmal sneezing, clear water-like snot, cough, chest tightness and wheezing becoming history. However, as a professional doctor, we still have to remind hay fever patients not to let up on the prevention and treatment. Hay fever is an allergic rhinitis and/or asthma caused by allergy to pollen. The pathogenesis of hay fever is IgE-mediated type I allergic reaction, in which the patient is sensitized by initial exposure to allergens, and then exposed to sensitive allergens again, and an abnormal immune response occurs. The flowering season of plants is obvious, and various plants have their own flowering period. When flowers bloom, their pollen floats in the air and can enter the respiratory tract of the body, which is an important disease-causing allergen. That is to say, patients who are allergic to one or more kinds of pollen will have allergic symptoms during the season when the pollen is dispersed, and will naturally become “good” after the flowering season. However, when the flowering season is just over, the pollen is not gone. When people come to cheer in the mountains and fields, the pollen that has fallen on the ground and not yet integrated into the soil floats again, causing allergy symptoms in patients allergic to this kind of pollen. Mr. Cao, who visited the clinic a few days ago, was one of them. The symptoms that had disappeared for half a month suddenly reappeared after a trip to the mountains, and were very heavy, with constant sneezing, a handful of snot, and red eyes. Mr. Wang was also a hay fever sufferer, and his legs were suddenly full of wind clusters after going to a barren meadow (allergy is a systemic disease). Another situation is that due to the existence of “pan-allergens”, many allergens have cross-reactivity with them, and when people who are allergic to a certain allergen encounter an allergen with cross-reactivity, they will also have allergic symptoms. In addition, hay fever patients have airway hyperreactivity and may experience symptoms when they encounter non-specific stimuli. It is also important to remind you that although the symptoms are gone after the flowering season, the disease is still present. The only thing is that there is no pollen in the air at this time, so there is no allergy. If no intervention is made, the natural course of allergic diseases is to have more and more allergens, more and more organs involved, and more and more severe symptoms. Different treatments for patients who also suffer from hay fever can lead to different results. Like Ms. Wang, who was diagnosed four or five years ago, but always got lucky and didn’t want to treat it after the flowering season every year, now her asthma is heavier and there are more allergens causing the disease. Ms. Tan, who came to the clinic almost at the same time as she did, has not only stopped wheezing, but her nasal symptoms have also basically disappeared after standard treatment. In short, if you want to stay away from hay fever, you need to receive standardized prevention and treatment as early as possible.