You have an allergic reaction, and you go to a pharmacy to get your usual anti-allergy medicine. You take the medicine and watch the symptoms disappear. Ever wondered how this happens?
Antihistamine, as the name suggests, works against histamines, a chemical released by our body that causes most of the allergy symptoms like sneezing, runny nose, watery eyes, rashes, swelling and itching. Histamines are important chemicals used by our immune system to repel pathogens and allergens that enter the body. The trick to treating an allergy is to block histamine from prompting the cells in our body to react against the allergens.
How do antihistamines work?
To understand how antihistamines work, one must know how histamine initiates the allergic reactions in our body. The cells in our body have a network of molecules called receptors in their individual cell walls. When histamine is released into the bloodstream in response to the presence of an allergen or pathogen in the body, the histamine receptors in the cells acknowledge the presence of histamine, and in response, the cells initiate the allergic reactions by swelling up, and causing the blood vessels to expand. This phenomenon is what you see as inflammation of skin. It also interferes with the nerves in the skin making it itchy.
Histamine receptors are of different types. The H1 receptors are responsible for inflammation, H2 receptors are involved in the process of regulating stomach acids, and H3 plays a crucial role in the neural transmission in the brain. The fourth receptor H4 is believed to be playing a role in regulating the immune system.
The role of antihistamine is to find out the histamine receptors on the cells and block histamine from reaching them. It does this by behaving just like a histamine molecule and attaching itself to the histamine receptors. Unlike histamine, an antihistamine molecule does not initiate any allergic response from those cells. This way, it prevents the allergic reactions from happening, and treats the symptoms quickly and efficiently.
Some antihistamines cause drowsiness. This happens when it blocks the H3 receptors, which is involved in neural communications in the brain. Now there are new second generation antihistamine tablets like Clarityn and Zirtek that do not interfere with the brain activities, and acts only on the receptors that receive the triggers for allergic reactions.
Basic safety precautions when using antihistamines
You should be very careful in choosing the right anti-allergy medication for your child. Some antihistamines tablets can cause dry mouth, upset stomach, sleepiness, and concentration problems in children. Children under the age of two years, should not be given antihistamine, because a wrong dose can affect their health adversely. For children above the age of 6 years, Piriton allergy tablets are recommended for instant relief, especially against rashes and other skin allergies. For relief from hay fever symptoms and other allergies in children, the banana flavoured Zirtek allergy relief solution is found to be very effective.