Antihistamines Antihistamines are used primarily to control symptoms of allergic conditions such as hay fever. They alleviate runny nose, sneezing and to a lesser extent, minimize conjunctivitis and breathing difficulties. Antihistamine drugs block the action of histamine, therefore reducing the allergy symptoms.
Antihistamines can also alleviate itching and rashes caused by food allergy.
Chemically, antihistamines comprise several classes, and a person who does not obtain relief from one type may benefit from another. For the best result, antihistamines should be taken before allergic symptoms get well established. Histamine Histamine, a chemical substance found in nearly all body tissues is released in response to injury by any foreign substances like pollen, dust, that it thinks are harmful. Allergic reactions are simply your immune system attempting to protect you against what it wrongly thinks is a harmful substance entering or touching your body. In doing so, your body often creates a chemical called Histamine to combat these mistaken enemies and this is what causes that annoying runny nose, congestion and sneezing that a patient suffers with an allergic attack.