food allergy nasal congestion

Nasal congestion caused by food allergy is essentially caused by a hypersensitivity reaction of the immune system to specific food ingredients that affects the nasal mucosa. After symptoms appear, the first priority is to stop eating the suspected allergen immediately and flush the nasal cavity with isotonic saline to relieve edema. If the symptoms are not relieved, second-generation antihistamines can be taken. If accompanied by throat tightness and difficulty breathing, seek medical attention immediately. It must not be treated as a common cold or rhinitis.

I have been working as a nurse in the allergy department for almost six years, and I have seen too many cases of people treating nasal congestion due to food allergies as colds. Not long ago, I met a girl who was born in 1995. She bought a box of fresh-cut pineapples on the way to get off work and ate half of the box while walking. When she got home, she felt her nose was stuffy. She thought it was the air conditioner in the subway that was freezing. She made a cup of cold medicine and then lay down. As a result, she was woken up in the middle of the night. Her whole nose was blocked and her upper lip was swollen. She rushed to the emergency department and found out that it was a food allergy induced by bromelain. She was given an injection of anti-allergic medicine and it cleared up in half an hour.

In fact, many people’s impressions of food allergies are still rashes and diarrhea. Little do they know that the nasal mucosa is also the hardest hit area for hypersensitivity reactions. If our immune system regards the ingredients in a certain food as invading harmful substances, it will quickly synthesize IgE antibodies to summon inflammatory cells and release mediators such as histamine and leukotrienes. These substances will flow to the nasal cavity along the blood circulation. The delicate submucosal blood vessels will immediately expand and tissue fluid will leak out. You can think of the nasal mucosa as a sponge soaked in water. In just ten minutes, it will swell to the point of blocking all the nasal gaps. It will also secrete clear nasal mucus continuously, but it will make you breathless.

Don’t think, “I’ve been eating this for decades and it’s fine, so it’s definitely not the fault of food.” The state of your immune system is not static. Staying up for most of the month, having just had a cold, or even hormonal fluctuations during pregnancy may cause immune dysfunction. Foods that were tolerated well before suddenly become allergens. I once met a man in his forties who has been eating shrimp for half his life. The last time he had half a pound of braised prawns for a late-night snack with his friends, he came home with a stuffy nose that lasted for two days. He sprayed rhinitis spray for several days to no avail. When he checked for allergens, he found out that he was suddenly allergic to shrimp. He even thought it was outrageous.

Not all food allergies cause nasal congestion immediately after eating. There is also a delayed-type hypersensitivity reaction, which may not appear until 6 to 12 hours after eating. Many people never think that the food is the problem. Last month, a high school student came to see a doctor. He said that he always had nasal congestion in the middle of the night for no reason and couldn't sleep well. After checking his food diary for almost half a month, he discovered that in the afternoon before each nasal congestion, he ate cashew nuts brought by his mother, only two or three at a time. The symptoms appeared slowly, so naturally the root cause could not be found.

As for how to deal with it in the future, there are actually two different ideas in the industry. One is more conservative, and is currently recommended by most clinicians: as long as it is clear that you are allergic to a certain food, avoid it completely in the future, do not touch it, and cut off the possibility of allergic triggers from the root. It is safe and almost risk-free. The other is oral immune tolerance therapy, which has been studied more frequently in recent years. Under the strict supervision of doctors, people gradually expose themselves to allergens starting from very small doses, slowly allowing the immune system to adapt, and finally achieve the effect of not being allergic even if they eat normal doses. This kind of therapy is suitable for some children. The effect on child patients is pretty good, but the risks are also high. If the dosage is not controlled well, it can range from nasal congestion and rash to severe anaphylactic shock. Therefore, it is definitely not recommended to try it blindly at home. If you really want to try it, you must go to the allergy department of a regular tertiary hospital and follow the doctor's instructions throughout the process.

Oh, by the way, there is another common pitfall that I have to remind you. Many people’s first reaction when they have a stuffy nose is to spray the decongestant spray such as oxymetazoline that they used for rhinitis before. It clears up the problem within a few minutes after spraying it. It feels very effective. However, this spray should not be used continuously for more than 7 days. If used too much, it will damage the nasal mucosa and induce drug-induced rhinitis. By then, the nasal congestion will become more stubborn. For nasal congestion caused by food allergy, if the symptoms are mild, flush two or three times with isotonic saline solution at about 37 degrees Celsius to flush out the secretions in the nasal cavity. The edema will subside a little and you will feel better. If it is still blocked after flushing, take a second-generation antihistamine such as loratadine or cetirizine, which can relieve the symptoms in basically half a day. The side effects are also small, and most of them will not affect work and school during the day.

Having said that, nasal congestion caused by food allergy can easily be confused with common colds and seasonal rhinitis. If your nasal congestion coincides with eating a certain type of food every time, don't be too troublesome. Go to the hospital for a serum-specific IgE test or skin prick test to find the allergens and avoid them, which is better than anything else. If one day after eating you not only have a stuffy nose, but also feel a tight throat, difficulty breathing, and large wheals on your body, don’t hesitate and go to the emergency room immediately. Allergies can be big or small, so don’t take it hard.