Allergy explained

When allergens first entered into the body,the plasma cells generate antibodies called IgE.
IgE attached themselves to the mastcells.

When the same allergen like pollen entered the body again,the allergen proteins attached to the IgE.

The IgE triggers the mast cells to produce histamine, prostaglandins, and leukotrienes which
caused the sneezing and wheezing and other symptoms found in allergic people.
Most common allergic conditions:
1) Allergic rhinistis (hay fever)
2) Asthma
3) Eczema --- Itchy skin conditions especially in children.
4) Rhinosinusitis---Inflammation of the sinuses.
5) Otitis media--- Inflammation of the middle ear.
6) Food allergy.
7) Anaphylactic shock--- occurs in people sensitive to penicillin, insect stings , shell fish and nuts. Symptoms seen as vomiting, cramps and sudden drop in blood pressure.