If you experience symptoms such as unexplained itching, a constant urge to rub your eyes, mouth ulcers, or even vomiting and diarrhea… be aware of chronic food allergy, also known as food intolerance.
Food intolerance is a complex hypersensitivity disease where the immune system mistakenly identifies certain foods entering the body as harmful substances, triggering an excessive protective immune response against them.
If you notice any of the following symptoms, it is recommended that you get tested for food intolerance:
Skin reactions: Itching, rashes, dryness/redness, exacerbation of eczema
Eyes: Reddened and watery eyes, rubbing of the eyes
Mouth: Swollen lips, mouth ulcers
Gastrointestinal reactions: Vomiting, constipation, diarrhea, abdominal pain
Respiratory reactions: Coughing, sneezing, runny nose
Note that food intolerance is categorized as chronic food allergy, detected by IgG levels in the blood; whereas allergen screening falls under acute allergies, detected by IgE levels in the blood. Some individuals may only exhibit chronic allergies, hence they may test positive for food intolerance but negative on allergen screenings.
Here comes the question: should you avoid eating the foods you test positive for, and if so, for how long?
In clinical practice, some patients blindly avoid certain foods long-term due to positive food intolerance tests, which is not advisable. This is particularly true for infants and young children who are still growing and developing, as avoiding multiple protein-rich foods can lead to malnutrition.
For some people without any symptoms who only discover food intolerance during health check-ups, there's no need to avoid these foods. Instead, continue monitoring your condition. If corresponding symptoms appear later, then consider avoiding the food.
Foods with an allergy grading of “+1” can be consumed less frequently. Foods graded “+2” and “+3” should be avoided for one month. If symptoms significantly improve, continue avoidance for another 2-5 months before reintroducing the intolerant foods once symptoms disappear. If there is no noticeable improvement after avoiding the food for one month, this suggests the original symptoms were unrelated to the food, and you do not need to continue avoiding it.
If an infant has milk intolerance, exclusive breastfeeding is recommended, with the mother avoiding milk. If breast milk is unavailable or mixed feeding is required, deeply hydrolyzed protein formula can be used.
Additionally, regarding parents' concerns about whether children with food intolerance can receive vaccinations, rest assured. Only a portion of children with acute food allergies (IgE positive), such as those allergic to eggs, cannot receive vaccines containing chicken embryo components (such as flu and meningococcal vaccines). However, food intolerance (IgG positive) is a form of chronic food allergy, and vaccinations can be administered safely.