Coughing and diarrhea may be symptoms of food allergies. Do I need to get tested for allergens?

A friend told Huazi that she had diarrhea every time she ate mangoes, and asked Huazi what to do. Huazi told her not to eat mangoes, because she was probably allergic to mangoes. She was a little surprised. Shouldn't allergies cause rashes and itchiness? Could it be diarrhea as well?

Huazi told her that allergic reactions are divided into four main types: immediate, cytotoxic, immune complex, and delayed. They manifest not only in itchy skin symptoms such as eczema and urticaria, but also in cough, asthma, rhinitis, conjunctivitis, gastroenteritis and many other symptoms.

1. Why do we have allergies? In fact, allergies are a state of war between the human immune system and allergens. Everyone has an immune system to protect the body from harmful pathogens from the outside world. After the immune system comes into contact with external substances, it will identify them. If it is identified as a harmless substance, it will let it go. If it is identified as a harmful substance, it will activate the immune response and eliminate or excrete the harmful substance from the body.

If the immune system identifies harmless substances as harmful substances and reacts too strongly, it will cause damage to normal tissues. This is called allergy. Common allergens include pollen particles, proteins in food, and drug ingredients, which can all become allergens and cause abnormal reactions in the human immune system.

2. There are many symptoms of allergies. When allergens come into contact with the human immune system, if they are identified as "harmful", the human body will produce corresponding antibodies. When encountering allergens again, the antibodies will be mobilized to bind to them and attack them. In this process, mast cells and basophils will release allergic mediators such as histamine and leukotrienes, causing allergic symptoms.

Rapid allergies are easy to detect and can quickly cause symptoms such as skin redness, rashes, itching, facial swelling, nasal congestion, runny nose, tears, and digestive tract reactions such as nausea, vomiting, and diarrhea. The most dangerous are throat edema and asthma, which can easily cause death from suffocation, and may also cause acute anaphylactic shock, leading to death from multiple organ failure.

Delayed-type allergies can cause some chronic symptoms, such as eczema, constipation or diarrhea, frequent abdominal pain, etc. However, delayed-type allergies may only appear several days after contact with allergens, and many people do not associate these symptoms with allergies.

3. Should we conduct food allergen testing? Food allergy is the most common cause, but generally speaking, it is not recommended to use allergen testing to conduct large-scale food allergy screening. The reason is that the accuracy of allergen testing is not high and there is a high false positive rate.

Taking the United States as an example, the American Society of Immunology has a reminder for IgE allergen testing that "both skin and blood tests may give false positive results." The American Academy of Pediatrics Parenting Encyclopedia also has a related reminder that "a positive skin or blood test is not sufficient to diagnose food allergies."

This means that the accuracy of allergen testing results is not very high. In skin tests, only about 60% of the results can correctly reflect the patient's allergic symptoms. If a large-scale allergen test is performed and then "foods to avoid" are selected based on the results, it is likely that a lot of foods that can be eaten normally will be missed, resulting in unbalanced nutritional intake.

Therefore, the real use of allergen testing is mainly as a final "confirmation". In other words, if you suspect that you are allergic to a certain food, you can use allergen testing to confirm it. However, the search for allergens is still mainly based on the "food elimination method", that is, removing possible allergic foods from the diet and then observing whether the allergic symptoms will improve.

4. Food allergies may change allergic diseases, which are difficult to cure. Allergic diseases need to be avoided for prevention. Anti-allergic drugs are used to treat the symptoms. However, the occurrence of allergic diseases is related to multiple factors such as genetics, environment, age, diet, lifestyle, immune status, etc., and it is difficult to explain it with a single factor.

As these factors change, the allergic state may also change. For example, many people are allergic to milk when they are young, but as they grow up, they gradually become tolerant; some people are allergic to pineapples, but as their immunity changes, the symptoms may gradually decrease or even disappear completely.

To sum up, in daily life, everyone should pay more attention to substances that cause allergic reactions, and try to avoid and reduce contact. If an immediate allergic reaction occurs, be sure to seek medical attention in time to avoid danger. The main function of food allergen testing is confirmation, but the accuracy rate is not high. If anti-allergic drugs are needed, it is recommended to use them under the guidance of a doctor or pharmacist. I am pharmacist Huazi, welcome to follow me and share more health knowledge.