How does an allergy impact the immune system?

An allergy impacts the immune system by causing it to mistakenly identify harmless substances, such as pollen, dust, or certain foods, as if they were dangerous pathogens. This misidentification triggers an inappropriate immune response. When the immune system encounters these benign substances, it reacts by producing antibodies, particularly Immunoglobulin E (IgE). This can lead to various allergic reactions, including inflammation, sneezing, itching, and even more severe responses like anaphylaxis in extreme cases.

The underlying issue in allergies is not a failure of the immune system to react, but rather an overreaction to substances that should not provoke a defense response. This characteristic helps to differentiate allergies from typical immune responses to actual threats, where the body appropriately identifies and combats pathogens. Understanding this mechanism sheds light on why individuals experience discomfort and health issues when exposed to allergens.