What is Allergy?
Allergy is often reffered to as the contemporary plague. Due to our way of life, we see more and more cases of allery everyday. It affects the lives of millions of people every day and sometimes it could be a potentially life threatening disease.
There are many different types of allergies. Many people in all countries have allergies and sometimes they cannot tell an allergy attack from a wide range of medical symptoms. An allergy attack can be anything from sneezing, blurred vision, dermatitis, hives, irritability to diarrhea, depression and muscle pain.
The most common allergies are:
* hay fever;
* (articles to follow)
Less common allergies include:
* Anaphylaxis
* (articles to follow)
Anaphylaxis is a sudden, severe, potentially fatal, systemic allergic reaction that can involve various areas of the body (such as the skin, respiratory tract, gastrointestinal tract, and cardiovascular system). Symptoms may occur within minutes to two hours after contact with the allergy trigger but, in rare instances, may occur up to four hours later. Anaphylactic reactions can be mild to life threatening. The annual incidence of anaphylactic reactions is about 30 per 100,000 persons, and individuals with asthma, eczema, or hay fever are at greater relative risk of experiencing anaphylaxis.
-- Food
-- Medication. It usually occurs within an hour after taking a particular medication. The inherited genetic tendency to develop allergies is of definite significance here but contrary to what many people believe the fact that a member of the family does have an allergy to particular drug does not mean that other members are at a higher risk of developing an allergy to the same medication.
-- Insect stings. While any insect can cause a severe allergic reaction the most common culprits are honeybees, bumblebees, yellow jackets, hornets, wasps, fire ants, and harvester ants. The reaction occurs usually just minutes after the sting. It can be local with just the tissue surrounding the spot, to the whole adjacent area going swollen, to getting a really serious where the person starts feeling nausea, low grade fever, and ultimately experience swollen tissue inside the throat, difficultybreathing, and wheezing and chest tightness. Sting bites account for up to 50% of all allergies induced deaths each year. To minimize your risk of getting stung by an insect do not wear bright clothing when working outdoors, avoid using strong perfumes or scented cosmetics, be careful when cooking or eating outside.
-- Latex. It is most common in people who are daily exposed to latex, like health care workers and individual who work for the latex industry. Kids who for some reason need multiple repeated surgeries develop this type of allergy as well. Some foods that cause cross reaction with latex can cause allergic reaction too. The most common of these are: bananas, European chestnuts, avocados, and kiwi. Less common are tomatoes, potatoes, and pitted fruits like cherries, plums, etc.
Less common causes include:
-- Food-Dependent Exercise - Induced Anaphylaxis (the allergic reaction is triggered by a combination of two factors - digestion of a specific food and physical exercise within a couple of hours after that)
-- Idiopathic Anaphylaxis - this is an anaphylactic reaction caused by an unrecognized trigger. The person exhibits every symptom of anaphylaxis, but no cause can be identified.
Anyone with a previous history of anaphylactic reactions is at risk for another severe reaction. Individuals with food allergies (particularly allergies to peanuts, nuts, fish and shell fish) and asthma (especially if accompanied by an array of other allergies) may be at increased risk for having a life-threatening anaphylactic reaction. A recent study showed that teens with food allergy and asthma appear to be at highest risk for a reaction because they are more likely to dine away from home, they are less likely to carry medications, and they may ignore or not recognize symptoms.
An anaphylactic reaction may begin with a tingling sensation, itching, or metallic taste in the mouth. Symptoms also may include hives, a sensation of warmth, asthma symptoms (coughing and wheezing, chest tightness and difficulty breathing), swelling of the mouth and throat area, difficulty breathing, vomiting, diarrhea, cramping, a sudden and severe drop in blood pressure, and loss of consciousness. The symptoms may appear right after exposure to a trigger or up to two hours after exposure. It may not look serious at first, but life-threatening reactions may progress over hours.
With some people the reaction begins then the symptoms go away only to return two to three hours later. This is called a "biphasic reaction." Often the symptoms occur in the respiratory tract and take the individual by surprise.
Epinephrine (the hormone adrenaline) is the most commonly used drug. It stops the further progression of the reaction and helps reverse the symptoms that have already occurred. It is obtained by prescription and is available as EpiPen® or Twinject™ for self injection. It is important to give yourself a shot right after you experience the firs symptoms. Antihistamines, steroids and asthma inhalers are given to help with the epinephrine but never instead of it, as they can not reverse thesymptoms that have already occurred as full as the epinephrine does.
What to do if you experience an anaphylactic reaction:
For additional, visit
The American Academy of Allergy, Asthma & Immunology.
ALLERGIC RHINITIS (HAY FEVER)
Symptoms of allergic rhinitis (Hay Fever) include itchy, runny, sneezy, or stuffy noses, and itchy eyes. Allergic rhinitis is a common illness affecting an estimated 20-40 million Americans, and resulting in 10 million lost days of school or work each year. Often caused by pollens from trees, grass or weeds, it is most commonly known as hay fever. Hay fever subsides with the onset of cold weather. Perennial allergic rhinitis, however, occurs year around and is caused by indoor allergens such as dust, mite, mold spores, and animal dander.
What Causes Allergic Rhinitis?
Chemical substances, such as histamine, are normally stored in mast cells in tissues of the body, including the nose and eyes. The allergic person forms antibodies against pollens and other allergens though they do not pose any threat to the immune system. These antibodies attach themselves to the mast cells, and when combined with the allergen the result is the release of histamine and other chemical substances from the mast cells. These chemical substances cause the allergic responses – the affected tissues go swollen and itchy, the membranes start to secrete mucus, the person experiencing the allergic reaction ends up sneezing and congested.
Treatment:
Avoidance is the best treatment for any allergy whenever possible. Keeping doors and windows closed in the home and in your car and avoiding vigorous outside activity will help to lessen your exposure during times when the pollen count is high. Removing pets from the home (or at least from your bedroom) and dust and mold control measures can significantly relieve symptoms due to perennial allergens. For dust control keep books in glass-door shelving units, put plastic casings on mattresses and pillows, wash your bedding in hot water once a week. For mold control wipe bathroom and kitchen surfaces with bleach often. Wash frequently your own hair as it collects pollen that irritates you. Avoid working in the garden or the yard. If it is absolutely necessary to do so, tale an antihistamine a couple of hours before you go out and wear a mask.
Antihistamines may relieve many hay fever symptoms by inhibiting the action of histamine on nasal and eye tissues. Avoid using the type of antihistamines that make you drowsy. Use a newer antihistamine which does not cause drowsiness in most people and is more effective. It is generally best to start with a low dose and increase the dose gradually until symptoms are controlled or until the maximum dose is reached.
Nasal decongestants act to decrease the swelling of the nasal tissue and the resulting feeling of stuffiness. Oral decongestants may cause sleeplessness and jitteriness. Topical nasal decongestants cause "rebound" congestion and irritation of the nasal passages if used more than 2-3 days. The stuffiness returns, but the nose spray doesn't help any more.
Chromolyn nose spray works by blocking the allergic reaction on the mast cell. It prevents or reduces the release of histamine and other chemical substances which cause the allergic symptoms. It does not cause drowsiness and does not cause "rebound" congestion. It is best started before exposure to known allergens, such as before the grass pollen season.
Nasal corticosteroids (Nasonex, Flonase) are effective in treating allergic symptoms and are best used locally to minimize side effects. It often takes several days to become effective. The quantity of the steroid used is minimal, it is applied directly to the affected tissue, and very little if any at all enter the blood stream, so most of the disturbing.
Oral corticosteroids (prednisone) are different in that when taken internally the risk of side effects is much greater than when used in small amounts locally, such as in the nose. Similarly, long acting injections of steroids have greater and really unpleasant effects (delaid growth in children, obesity in adults to mention just a few). When possible, doctors prefer to treat with topical steroids rather than oral or injectable. Short bursts of oral steroids on alternate day use minimizes side effects.
Eye drops (Naphcon-A, Opcon-A, Vasocon-A): Antihistamine decongestant eye drops act similarly to oral preparations and given quick relief of allergic symptoms of red, itchy, watery eyes. Opticrom and blocks the release of chemical substances from the mast cells around the eyes, thus preventing or reducing allergic symptoms.
Saline (salt water) nose drops are often helpful in relieving nasal symptoms. You may purchase these already mixed (Salinex, Ocean) or you may make your own by mixing 1 cup of water, 1/2 teaspoon salt, and a pinch of baking soda. Inhale a handful of this solution at a time. Discard the home-made solution after twenty-four hours because it contains no preservative. Home made solution is always better than the ready made ones as it has no preservatives that reduce the movement of the cilia inside the nose and thus prevent them form discarding mucus, bacteria, viruses or other foreign agents that end up in the nasal cavity.
VASOMOTOR RHINITIS
Nasal passages have rich supplies of blood vessels. When they become engorged with blood, the nose gets stuffy. As fluid leaks out of the vessels, a veritable Niagara of mucus flow can start and some of it can leak back into the throat (post-nasal drip). It is all a part of vasomotor rhinitis - vasomotor for the blood vessel connection and rhinitis for the nasal tissue inflammation.
You cannot really call this an illness as much as an exaggeration of normal events. The cells involved produce up to a pint of fluid a day, even in normal people. Patients with vasomotor rhinitis are super-sensitive to the irritants that give rise to all of this nasal activity.
Temperature or humidity changes, strong odors, alcohol, tobacco smoke, even changing a position in bed at night can cause it. You have to avoid such situations. It is a chronic problem, so don't expect time to take care of it.
A lot of vasomotor rhinitis sufferers get relief from decongestants taken orally. They can cause tissue constriction and get you over particularly bad times. Those that contain pseudoephedrine help. Some people may have such a severe onset of the problem that they need cortisone drugs applied to the nasal membranes.
Over-the-counter decongestant nasal sprays may give temporary relief, but it is usually quite short-lived and they can, with excessive use, cause rebound swelling worse than the original problem. Try to get along without them.
Allergy is a medical term which is used to describe a reaction within the body to a substance (which is normally harmless itself), which results in an immune response (including Type I hypersensitivity in which a person's body is hypersensitised and develops IgE type antibodies to typical proteins) and a reaction that causes symptoms and disease in a predisposed person. That can be a source of mild or extreme inconvenience, and even a great deal of misery.
Allergens are the substances causing the reaction in a hypersensitised person. The word allergy derives from the Greek words allos meaning "other" and ergon meaning "work".
Type I hypersensitivity is characterised by excessive activation of mast cells and basophils by immunoglobulin E resulting in a systemic inflammatory response that can result in symptoms as benign as a runny nose, skin rash and itchy eyes, to life-threatening anaphylactic shock and sometimes fatality. It effects the sense of sight, smell, tastes and touch and is the result of the body's immune system overreacting to normally harmless substances.
What causes an Allergy?
Allergic reactions are caused by substances in the environment known as allergens. Almost anything can be an allergen different for people. Allergens contain protein, which is often regarded as a constituent of the food we we eat.
In fact it is an organic compound, containing hydrogen, oxygen and nitrogen, which form an important part of living organisms.
The most common allergens are:
* pollen from trees and grasses;
* house dust mite, moulds;
* pets such as cats and dogs;
* insects like wasps and bees;
* industrial and household chemicals;
* medicines, and
* foods such (as milk and eggs).
Less common allergens include:
* nuts,
* fruit and
* latex.
There are some non-protein allergens which include drugs such as penicillin. For these to cause an allergic response they need to be bound to a protein once they are in the body.
An allergic person's immune system believes allergens to be damaging and so produces a special type of antibody (IgE) to attack the invading material. This leads other blood cells to release further chemicals (including histamine) which together cause the symptoms of an allergic reaction.
The most common symptoms are:
sneezing , runny nose, itchy eyes and ears, severe wheezing, coughing shortness of breath, sinus problems, a sore palate and nettle-like rash.
It should be understood that all the symptoms mentioned can be caused by factors other than allergy. Indeed some of the conditions are diseases in themselves.
When asthma, eczema, headaches, lethargy, loss of concentration and sensitivity to everyday foods such as cheese, fish and fruit are taken into account the full scale of allergy be appreciated.