Allergy Causes
Allergic reactions can impact different parts of the body. Some allergies irritate the skin, or the eyes. Others cause respiratory problems. Some may upset the stomach, and even cause vomiting, while still others can disrupt the functioning of major organs.
Common allergic reactions that affect the skin include contact dermatitis, atopic dermatitis, and hives (uticaria). Contact dermatitis occurs when someone’s skin comes in contact with an allergen, or with an irritant such as poison ivy. It often results in the outbreak of an itchy, blistering rash, sometimes with weeping pustules. Atopic dermatitis usually comes from something the patient ingested or something airborne that he or she inhaled. Atopic dermatitis makes the skin swell and dries it out by preventing it from producing sufficient moisture. Atopic dermatitis causes a specific type of chronic and severe eczema. Hives, or uticaria, is an umbrella term to describe a generalized itchy rash.
The source of hives is often very difficult to determine. Hives can have both internal causes—such as infection or the ingestion of an allergen—or external causes—like contact with an irritant. An allergic reaction that affects the eyes is called allergic conjunctivitis, or allergic pink eye. Allergic conjunctivitis is caused by airborne allergies. It takes the form of red, swollen, itchy, burning, and watery eyes. One major cause of allergic reaction that involves the respiratory system is dust mites. Because dust mites eat animal and human dander, their droppings cause a lot of people to wheeze. Dust mites can even exacerbate asthma. Ear, nose and throat reactions are most frequently caused by airborne allergens such as tree pollen or perfumes. Allergic rhinitis, or hay fever, is the most common allergy affecting the nose. It produces symptoms much like those of the common cold. Respiratory, and ear, nose, and throat reactions alike can also be spurred by pet allergies. Animals secret proteins that can cause an allergic reaction when you come in contact with them either on the animal’s skin or when they’re floating in the air. Even an animal’s drool can trigger an allergic reaction in a human! You may also be surprised to hear that some people are actually more sensitive to certain breeds of dogs or cats. Sensitivity to dog dander versus cat danger also varies from on allergy sufferer to another. Foods are of course most often responsible for allergic reactions that affect the stomach, although drug allergies can also be the culprit. Painkillers, antibiotics, anti-seizure medications, and contraceptive medications are among the drugs that have been known to produce allergic reactions with side effect ranging anywhere from sun hives to anaphylaxis.
The most severe type of allergic reaction is anaphylaxis. While the occurrence is fairly rare, a food allergy or an insect sting can trigger it. Insect sting allergies cause the white blood cells to release an antibody that breaks up the protein in the insect’s venom. That antibody makes your cells produce histamine, which causes a general allergic reaction. Anaphylaxis only occurs in people whose body stores an excess of that antibody. It rarely occurs the fist time a person is stung. Rather, the antibody build up is a sensitization process that results from repeated incidents.