Answers

Ajay
Aug 1, 2020

The allergen can be pollen grains, spores or dust particles.
When the allergens are inhaled or enter body system, they stimulate body to produce IgE antibodies and trriger an anti-allergic reaction. The chemical such as histamine  and serotonin are released from mast cells, in respons to allergen, thereby causing dilation of blood vessels. The other symptoms of allergy, i.e. sneezing, watery eyes,  running nose, etc