Antihistamines and steroids are administered to treat which of the following?

Which of the following is $NOT$ relevant in the context of treating allergies?

Which immunoglobulin levels increase during an allergic reaction?

What are substances that trigger an allergy called?

Assertion : Mast cells in the human body release excessive amounts of inflammatory chemicals,which cause allergic reactions.
Reason : Allergens in the environment on reaching human body stimulate mast cells in certain individuals.

$A$ person shows symptoms like sneezing,watery eyes,running nose,and difficulty in breathing upon exposure to certain substances in the air. Which type of antibody is produced during such a condition?