Multiple Allergies and the Symptom Threshold

Why don't I have symptoms all the time? 

Everyone has their own unique combination of allergic triggers and not all of them are obvious. You may be sensitized to several allergen sources, but your sensitization may not be enough to trigger symptoms when you are exposed to only one of them. But when you encounter multiple substances you’re allergic to at the same time, they can add up, and you may start experiencing symptoms, such as itchy eyes or a runny nose.1,2

Determining if you’re allergic and identifying your allergic triggers can help you stay below your symptom threshold—the point where you start experiencing allergy symptoms.

Allergic triggers can add up.

Most people with allergies—up to 80 percent—are allergic to multiple allergens.3 And for some of these people; symptoms may appear only when they encounter two or more things they’re allergic to at the same time.

Minimizing your exposure to your allergic triggers may help lessen or eliminate your symptoms. For example: 


You could have a low-level allergy to dust mites, mold, and grass pollen. During large parts of the year you’re exposed to dust mites and mold, but may have little to no symptoms.

But in the spring, when pollen is in the air, you may experience symptoms. You then might think that you have only a pollen allergy. But without a test you won’t know for sure.


Your best defense against your allergic symptoms is to know what’s causing them and to avoid those triggers. This doesn’t necessarily mean you’ll have to cut everything you’re allergic to out of your life. You'll just have to reduce your exposure enough to get below your symptom threshold—the level where you start to experience symptoms.


Tools for Understanding Allergies


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  1. Wickman M. When allergies complicate allergies. Allergy. 2005;60 (Suppl 79):14–18.
  2. Burbach GJ, et al. GA2 LEN skin test study II: clinical relevance of inhalant allergen sensitizations in Europe. Allergy. 2009;64:1507-15.
  3. Ciprandi G, Alesina R, Ariano R, et al. Characteristics of patients with allergic polysensitization; the polismail study. Eur Ann Allergy Clin Immunol. 2008;40 (3);77-83.
  4. Boyce J, Assa’ad A, Burks AW, et al. Guidelines for the diagnosis and management of food allergy in the United States: Report of the NIAID-sponsored expert panel. J Allergy Clin Immunol. 2010;126 (6):S1- 58.