What Is a Histamine Blocker?

Histamines are biologically activated chemicals released by our bodies as a response to an allergen. Histamines cause capillaries to expand, sending excess fluid to the skin. The excess fluid results in swelling and the increased capillary size causes the skin to turn red. Many people who suffer from allergens avoid such reactions by taking a medication known as a histamine blocker.

• An insect bite is an allergy trigger.

H1 and H2 Receptors

• According to Alpha Online, a division of Environmed Research, the histamine response produces two different types of reactions that are dependent on which receptor the histamine triggers. When H1 receptors are triggered by histamines, they produce headaches, swelling, skin sensations, respiratory responses and anxiety. However, when H2 receptors are triggered by histamines, they produce an increase in gastric acids.

Antihistamines

• Antihistamines are medications that block the symptoms that are caused by the H1 receptors. The Department of Pediatrics at the University of Hawaii John A. Burns School of Medicine reports that diphenhydramine is one of the most commonly used antihistamines used to block histamines reactions. The vast majority of antihistamine medications are available over the counter and will provide relief for up to 24 hours per dose.

H2 Blockers

• Although many ulcers are caused by a bacteria known as Helicobacter pylori (H. pylori), The College of Family Physicians of Canada explains that an increase in stomach acid can also contribute to the development of ulcers. Excessive amounts of gastric acid such as that triggered by the H2 receptor can actually burn the inner lining of the digestive tract. In the book "Common Diseases: Their Nature, Presentation and Care," authors John Fry and Gerald Sandler report that the most commonly used H2 blockers are cimetidine and diazepam that both work to prevent and heal ulcers. Both of these medications are available by prescription, but cimetidine also has an over-the counter-version. Each of these medications aid in reducing the amount of gastric acid produced by H2 receptors.

Immunotherapy

• It is possible for our bodies to develop 'natural' histamine blockers. The American College of Allergy, Asthma and Immunology reveals that allergy shots can help the body build up its own antigens that can in turn block histamine response to allergy triggers. Immunotherapy injections are usually administered over a serious of weeks and usually contain a small amount of the allergen that you are allergic to, causing your body to create its own line of defense to block histamines.

Knowing Your Triggers

• A proactive way to guard against histamine responses is to know what triggers your allergies. The American Lung Association explains that smoke, fragrances, dust mites, pollen, insect bites and animal dander are the most common allergy triggers reported. An allergist can administer tests that can help to determine what you are allergic to and the best way to block your body's response.