What Are Histamines?

The American Academy of Allergies, Asthma and Immunology, known as AAAAI, estimates that nearly 50 million Americans suffer from allergies. This common condition is a result of a biochemical response to what your body perceives as an invasion. Histamine is one of the chemical substances responsible for the uncomfortable symptoms associated with allergies. It also plays an important role in the body's normal immune response.

Immune Response

• When the body detects the presence of a potentially harmful substance, the brain triggers your immune system to release antibodies. These antibodies seek out and destroy the intruder to protect the body from infection from viruses and bacteria. Histamines are one of the body's protective mechanisms that dilate blood vessels, stimulate gland secretions and release protein from the cells to fight off and flush away foreign bodies.

Allergic Response

• Where histamines get a bad rap is when they act up against normal, everyday substances. This response to normal substances is an allergic reaction. Allergens vary from person to person, but can include pollen, dust, mold or animal dander. Allergens trigger a reaction within the body because the body perceives it as dangerous. Once antibodies have captured an allergen, histamines are released. This often occurs in the lungs, nasal passages and throat. In the process of gathering help from other antibodies to fight off the offending substance, histamines cause inflammation, mucus production, skin reactions and other symptoms of allergies. These symptoms often translate into itchy and watery eyes, swollen skin, eyes and lips, and upper-respiratory problems such as sneezing, wheezing, coughing and a runny nose. The AAAAI points out that it is not yet understood why some people have allergies while others do not. It has been determined, however, that a family history of allergies often leads to the development of allergies in subsequent generations.

Food Sensitivities

• Histamines and amines, which are histamine-like substances, are present in many of the foods you eat. Fish, nuts, aged cheeses and meats, and alcoholic beverages contain histamines that can cause allergy-like symptoms such as itching, sneezing, headaches, hives, flushed skin and difficulty breathing. This type of reaction to histamine-rich foods is not an immune response and is different from a true food allergy. The easiest way to prevent these reactions is to avoid the food or beverage, once you have identified what is triggering your symptoms.

Skin Reactions

• Histamines dilate the blood vessels, causing itching, flaking and reddening of the skin. Urticaria, or hives, are pink, red or flesh-colored welts that can rise up when histamine is released. They cause swelling under the skin and often appear all over the body. Hives are caused by allergic sensitivities to a variety of irritants such as chemicals, soaps, detergents, fabrics, medications, foods and certain types of vegetation.

Airway Response

• Histamine release also causes smooth muscles to contract. This contraction can occur in your airways and result in shortness of breath. It also causes you to suffer from sinus inflammation and excessive mucus production, resulting in cough, congestion and nasal drainage. In moderate to severe cases, coughing, tightness in the chest and narrowing of the airways can make it difficult to breathe. In rare cases, this can be fatal. Many individuals with asthma also have allergies. In these cases, it is often the exposure to allergens that triggers an asthma attack.

Treatment Options

• Fortunately, there are numerous anti-histamines on the market to manage allergies. Anti-histamines are a group of drugs aimed to interrupt the allergic response and provide relief for allergy sufferers. They work by either blocking the release of histamines in the body or by neutralizing them once released. Immunotherapy, or a series of allergy shots, is another option for allergy suffers. Gradually increasing the exposure to your allergens can lessen your body's response over time.