Allergy season. Everyone knows about it, and everyone hates it. And, at least one out of every 5 Americans suffers from allergies as reported by WebMD. Common causes of allergy symptoms include food allergies such as peanut allergy or milk allergy, and seasonal allergies resulting from grass, weed, tree pollen, or various molds. Cat allergies and dog allergies can also cause miserable symptoms such as itchy eyes, sneezing, nasal congestion, and wheezing. Allergic skin conditions can cause a rash and itchy skin.
WebMD reports that allergies are an abnormal response of the immune system. People who have allergies have an immune system that reacts to a usually harmless substance in the environment. This substance (pollen, mold, animal dander, etc.) is called an allergen. Allergies are a very common problem, affecting at least 2 out of every 10 Americans. When a person is exposed to an allergen, a series of events takes place:
--The body starts to produce a specific type of antibody, called IgE, to bind the allergen.
--The antibodies attach to a form of blood cell called a mast cell. Mast cells can be found in the airways, in the GI tract, and elsewhere. The presence of mast cells in the airways and GI tract makes these areas more susceptible to allergen exposure.
--The allergens bind to the IgE, which is attached to the mast cell. This triggers a reaction that allows the mast cells to release a variety of chemicals including histamine, which causes most of the symptoms of an allergy, including itchiness or runny nose.
If the allergen is in the air, the allergic reaction will likely occur in the eyes, nose and lungs as reported by WebMD. If the allergen is ingested, the allergic reaction often occurs in the mouth, stomach, and intestines. And, sometimes enough chemicals are released from the mast cells to cause a reaction throughout the body, such as hives, decreased blood pressure, shock, or loss of consciousness. Allergy symptoms can be categorized as mild, moderate, or severe (anaphylactic). Mild reactions include those symptoms that affect a specific area of the body such as a rash, itchy, watery eyes, and some congestion. Mild reactions do not spread to other parts of the body. Moderate reactions include symptoms that spread to other parts of the body. These may include itchiness or difficulty breathing. A severe reaction, called anaphylaxis, is a rare, life-threatening emergency in which the response to the allergen is intense and affects the whole body. It may begin with the sudden onset of itching of the eyes or face and progress within minutes to more serious symptoms, including abdominal pain, cramps, vomiting, and diarrhea, as well as varying degrees of swellings that can make breathing and swallowing difficult. Mental confusion or dizziness may also be symptoms, since anaphylaxis causes a quick drop in blood pressure. Most allergies are inherited, which means they are passed on to children by their parents. People inherit a tendency to be allergic, although not to any specific allergen. When one parent is allergic, their child has a 50% chance of having allergies. That risk jumps to 75% if both parents have allergies.
According to the National Institutes of Health (NIH), an allergy is a reaction of your immune system to something that does not bother most other people. Scientists think both genes and the environment have something to do with it. Normally, your immune system fights germs. It is your body's defense system. In most allergic reactions, however, it is responding to a false alarm. Although allergies can make you feel bad, they usually won't kill you. However, anaphylaxis is life-threatening. People who have allergies often are sensitive to more than one thing. The substances that often cause reactions are:
Approximately 50 million Americans suffer from some form of allergic disease, and the incidence is increasing as indicated by the NIH. In many cases, the allergic reaction typically continues: these newly released mediators recruit other inflammatory cells to that site, resulting in additional inflammation. Many symptoms of chronic allergic disease—such as swelling, excessive mucus and hyperresponsiveness to irritating stimuli—are the result of tissue inflammation due to ongoing exposure to allergens. Major allergic diseases include:
--Allergic rhinitis, or “hay fever”
--Allergic conjunctivitis (an eye reaction)
--Atopic dermatitis, or allergic skin reactions
--Urticaria, also known as hives
--Severe allergic reactions to substances such as food, latex, medications, and insect stings
--Problems commonly resulting from allergic rhinitis—sinusitis and otitis media (ear infections)
Antibodies circulate in the bloodstream and are present in almost all bodily fluids according to the NIH. They help to capture unwanted invaders. People who have allergies have an antibody called Immunoglobulin E, or IgE. When allergens first enter the body of a person predisposed to allergies, a series of reactions occurs and allergen-specific IgE antibodies are produced. Following IgE production, these antibodies travel to cells called mast cells, which are particularly plentiful in the nose, eyes, lungs and gastrointestinal tract. The IgE antibodies attach themselves to the surface of the mast cells and wait for their particular allergen. Each type of IgE has specific “radar” for one type of allergen only. That's why some people are only allergic to cat dander (they only have the IgE antibodies specific to cat dander) and others seem to be allergic to everything (they have many more types of IgE antibodies.)
The next time an allergic individual comes into contact with the allergens to which he or she is sensitive, the allergens will be captured by the IgE. This initiates the release of chemical “mediators” such as histamine and other chemicals from the mast cells. These mediators produce the symptoms of an allergic reaction, such as swelling of tissues, sneezing, wheezing, coughing and other reactions. The allergic reaction typically continues: these newly released mediators recruit other inflammatory cells to that site, resulting in additional inflammation. Many symptoms of chronic allergic disease—such as swelling, excessive mucus and hyperresponsiveness to irritating stimuli—are the result of tissue inflammation due to ongoing exposure to allergens. It is not yet fully understood why some substances trigger allergies and others do not, nor why every person does not develop an allergic reaction after exposure to allergens. Symptoms of atopic dermatitis, also called eczema, often result from allergen exposure to the skin as reported by the NIH. Dermatitis symptoms include itching, reddening, and flaking or peeling of the skin. Symptoms begin in childhood for 80% of those with atopic dermatitis. Dermatitis often precedes other allergic disorders; over 50% of those with atopic dermatitis also develop asthma. Urticaria, or hives, another allergic skin reaction, is characterized by itchy red bumps that can occur in clumps and be either large or small. Hives are often triggered by infection, certain foods or medications. Foods commonly associated with hives include nuts, tomatoes, shellfish and berries. Medications include penicillin, sulfa, anti-seizure medications, phenobarbital and aspirin. Asthma is a chronic lung disease that affects more than 17 million Americans and is characterized by coughing, chest tightness, shortness of breath and wheezing. Allergic rhinitis is considered a risk factor in developing asthma: up to 78% of those with asthma also have allergic rhinitis. When an individual experiences asthma symptoms, the inflamed airways become constricted so it becomes more difficult to breathe through the narrowed air passages. For people with allergies, inhaling allergens may produce increased inflammation of the airway lining and further narrowing of the air passages. Asthma may also occur as a result of other stimuli, such as respiratory tract infections or exposure to irritants.
Individuals, according to the NIH, who have allergies to specific foods may have severe and possibly life-threatening reactions if they eat them. The most common food allergy triggers are the proteins in cow's milk, eggs, peanuts, wheat, soy, fish, shellfish and tree nuts. Food allergy occurs more frequently in children than adults. Many of these children may lose their sensitivity to particular foods over time. Foods and other allergens, including penicillin, insect stings and latex, can trigger a severe, systemic allergic reaction called anaphylaxis. Anaphylaxis is caused by swelling throughout the body, and can involve several organ systems. Symptoms of anaphylaxis include a feeling of warmth, flushing, tingling in the mouth or a red, itchy rash. Other symptoms may include feelings of light-headedness, shortness of breath, severe sneezing, anxiety, stomach or uterine cramps, and/or vomiting and diarrhea. In severe cases, patients may experience a drop in blood pressure that results in a loss of consciousness and shock. Plus, without immediate treatment with an injection of epinephrine (adrenalin), anaphylaxis may be fatal.
The National Institute for Immunology says that an allergist is best qualified to treat allergic diseases. To determine if you have an allergy, your allergist will take a thorough medical history and perform an exam. If indicated, he or she will then perform allergy skin testing, or sometimes blood testing, to determine precisely which substance is causing your allergy. Once your allergy triggers are identified, your physician can help you establish a treatment program. The first step is to minimize your exposure to your particular allergens to whatever extent possible. Your physician may also prescribe medications to reduce allergic symptoms as well as inflammation. Immunotherapy, also known as allergy shots, may also be recommended to modify your immune response. For many patients, immunotherapy can help diminish their reactions to allergens.
In summary, an allergic reaction is a complex chain of events that involves many cells, chemicals and tissues throughout the body. While there is not yet a cure for allergic disease, there are many treatments available to lessen symptoms. See your allergist to determine the best course of treatment.
Until next time. Let me know what you think.