Should My Child Retest for Allergens After 5 Years of No Reaction?

Do I need to redo an allergy test from five years ago?

Hello Dr.
Hsiao,
My son is 19 years old and has had allergy symptoms since he was young.
When he was 14, he underwent an allergen test (M25-130-Z MAST ALLERGY) at Chang Gung Memorial Hospital, which tested for 36 allergens, all of which returned a value of 0 (Non-Detectable).
His allergy symptoms improved for a while, but recently they seem to have returned.
I would like to ask the doctor if it is necessary for my son to retake the allergen test for these 36 allergens.
Generally speaking, is there a significant chance that something that was not an allergen five years ago could become an allergen after five years? Thank you, doctor.

Yang, 50~59 year old female. Ask Date: 2023/07/04

Dr. Xiao Kaiwen reply Pediatrics

During the transition from infancy to childhood and then to adolescence, it is possible for allergic predispositions to change.
Therefore, allergen testing that was conducted over five years ago may no longer be accurate, and it may be worth considering retesting.
After that, further testing may not be necessary.

Reply Date: 2023/07/04

More Info

When considering whether your child should retest for allergens after five years of no reaction, there are several factors to take into account. Allergies can be complex and may change over time due to various influences, including environmental factors, changes in the immune system, and even lifestyle changes.
Firstly, it is important to understand that allergies can develop at any age. Just because your child tested negative for specific allergens five years ago does not guarantee that he will remain non-reactive to those same allergens indefinitely. The immune system can change, and new allergens can be introduced into the environment that may provoke a reaction. For instance, common allergens such as pollen, dust mites, pet dander, and certain foods can elicit allergic responses in individuals who previously had no issues with them.

Given that your child is now experiencing a resurgence of allergic symptoms, it would be prudent to consult with an allergist or a healthcare provider specializing in allergies. They can evaluate your child's current symptoms, medical history, and any changes in his environment or lifestyle that may contribute to his symptoms. A thorough assessment may include a physical examination and a discussion about the specific symptoms he is experiencing, such as sneezing, itching, rashes, or respiratory issues.

In general, retesting for allergens can be beneficial, especially if there has been a significant change in symptoms or if new allergens are suspected. The likelihood of previously non-reactive allergens becoming problematic can vary. Some studies suggest that certain allergens, particularly environmental ones, may become more relevant as a child ages and is exposed to different environments, such as school or extracurricular activities.
Moreover, if your child has developed new symptoms that are consistent with allergic reactions, retesting could help identify specific triggers. This information can be invaluable for managing his symptoms and improving his quality of life.
In summary, while there is no definitive answer to whether your child should retest for allergens, the presence of new symptoms after a period of stability is a strong indicator that retesting may be warranted. Consulting with a healthcare provider will provide you with tailored advice based on your child's specific situation. They may recommend a repeat of the previous allergy tests or suggest alternative testing methods, such as skin prick tests or specific IgE blood tests, to identify any new or previously undetected allergies.
In conclusion, allergies can evolve over time, and it is essential to stay vigilant, especially when symptoms reappear. Regular follow-ups with an allergist can help ensure that your child receives appropriate care and management for his allergic conditions.

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