Home > Allergy Symptoms
The signs and symptoms of airborne allergies are familiar to many.
In sensitive people, as soon as the allergen lands on the lining inside the nose, a chain reaction occurs that leads the mast cells in these tissues to release histamine and other chemicals. The powerful chemicals contract certain cells that line some small blood vessels in the nose. This allows fluids to escape, which causes the nasal passages to swell—resulting in nasal congestion. Histamine also can cause sneezing, itching, irritation, and excess mucus production, which can result in allergic rhinitis.
Other chemicals released by mast cells, including cytokines and leukotrienes, also contribute to allergic symptoms.
Some people with allergies develop asthma, which can be a very serious condition. The symptoms of asthma include
Courtesy: National Institute of Allergy and Infectious Diseases