Question 1

Why does the immune system attack harmless things like pollen?

Accepted Answer

The immune system can mistakenly tag a harmless molecule as a dangerous invader, producing IgE antibodies against it. Many researchers believe this machinery originally evolved to fight parasitic worms and now misfires on pollen, food, and pet dander in their absence.

Question 2

What is the hygiene hypothesis?

Accepted Answer

Proposed by David Strachan in 1989, the hygiene hypothesis suggests that reduced early-life exposure to microbes and parasites leaves the immune system poorly calibrated, making it more likely to overreact to harmless substances. It helps explain why allergy rates rose fastest in the cleanest, most developed nations.

Question 3

What happens in the body during an allergic reaction?

Accepted Answer

When an allergen binds to IgE antibodies on mast cells, those cells rupture and release histamine within minutes. Histamine widens blood vessels, leaks fluid, and tightens airways, causing itching, swelling, and in severe cases the life-threatening collapse known as anaphylaxis.

allergies

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