Should You Repeat Allergy Testing After 5 Years? Changes in Allergens

Is it necessary to repeat the allergen testing for the same allergens that were tested five years ago?

Hello Dr.
Tseng: I am 21 years old and have had an allergic constitution since childhood.
When I was 16, I underwent an allergen test (M25-130-Z MAST ALLERGY) at Chang Gung Memorial Hospital, which tested 36 allergens, all of which showed a value of 0 (Non-Detectable).
I would like to ask the doctor if I should retest these 36 allergens since I am currently experiencing some allergic symptoms, but I am unsure of the specific allergens.
Generally speaking, is there a significant chance that substances that were not allergens five years ago could become allergens after five years? Thank you, doctor.

Zhong, 20~29 year old female. Ask Date: 2023/05/23

Dr. Zeng Guosen reply Internal Medicine

Over 90% of individuals with chronic allergies cannot identify the cause.
Even though allergens may change over a span of five years, MAST ALLERGY testing for 36 allergens still does not alter the treatment strategy.
Thank you.

Reply Date: 2023/05/23

More Info

When it comes to allergy testing, especially after a significant period like five years, it's essential to consider several factors that could influence your allergic responses. Allergies can change over time due to various reasons, including environmental changes, lifestyle modifications, and even changes in your immune system as you age.
In your case, since you were tested at 16 and found to have non-detectable levels for 36 allergens, it is indeed possible that your immune system has evolved since then. Allergies can develop at any age, and substances that were previously tolerated may become problematic later in life. This phenomenon is particularly common with environmental allergens such as pollen, dust mites, and pet dander, which can vary in prevalence and potency over time.

Given that you are now experiencing allergic symptoms, it would be prudent to consider re-testing for allergens. Here are some reasons why repeating the allergy test could be beneficial:
1. Changes in Allergen Exposure: Over the past five years, you may have been exposed to new allergens or increased exposure to previously encountered allergens. For example, moving to a new area, changes in household pets, or even changes in your environment (like starting college or a new job) can introduce new allergens.

2. Age-Related Immune Changes: As you grow older, your immune system matures and can react differently to allergens. This means that substances that were once harmless may trigger allergic reactions as your body’s immune response changes.

3. Symptom Evaluation: If you are experiencing new or worsening allergic symptoms, identifying the specific allergens responsible can help you manage your symptoms more effectively. Knowing what you are allergic to can guide you in avoiding triggers and seeking appropriate treatment.

4. Advancements in Testing: Allergy testing methods have improved over the years. Newer tests may provide more accurate results or test for a broader range of allergens than those available five years ago.

5. Personal Health Changes: Any changes in your health status, such as new medications, illnesses, or lifestyle changes, can also affect your allergic responses. A new allergy test can help clarify if these factors are contributing to your symptoms.

In conclusion, while it is not guaranteed that allergens will change significantly over a five-year period, the possibility exists, and given your current symptoms, it would be wise to consult with an allergist. They can provide a comprehensive evaluation and determine whether re-testing is necessary. This approach will help you identify any new allergens and develop an effective management plan for your allergic symptoms. Remember, managing allergies is not just about avoiding triggers; it also involves understanding your body and how it reacts to the environment around you.

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