Allergy
Date of last update: 25 July 2012
Allergy refers to an adverse reaction of the body to a particular substance in the environment. Many substances that cause allergies are not harmful and have no effect on those people who are not allergic. Any substance that triggers an allergic reaction is called an allergen. Some of the most common allergens include pollen, dust mites, mold and pets.
What are allergies?
Allergy means an adverse reaction of the body to a particular substance in the environment. Many substances that cause allergies are not harmful and have no effect on those who are not allergic. Any substance that triggers an allergic reaction is called an allergen. Some of the most common allergens include pollen, dust mites, mold and pets. Few other common allergens include nuts, fruits and latex. An allergy develops when the body's immune system reacts to an allergen, as if it were a threat, an infection, by producing antibodies to fight it. This process is called immune response. The next time the person comes into contact with the allergen, the body "remembers" previous exposure and produces more antibodies. This causes the release of chemicals in the body leading to an allergic reaction. The most common disorders caused byallergy include asthma, eczema and hay fever. Symptoms may include:
Symptoms depend on how a person came into contact with the allergen. For example, you may have respiratory problems if inhaled pollen.
What are the symptoms of allergies?
Allergic reactions do not occur the first time you come into contact with the allergen, but after being exposed to. This is because the immune system must develop a sensitivity to the allergens before they become allergic. Typical reactions include irritation and allergic inflammation.
Symptoms may include:
It is important to remember that these symptoms may be caused by other diseases, so it is best to consult your doctor. Rarely, an allergy can lead to a severe allergic reaction called anaphylactic shock (or anaphylaxis), which can be fatal. Most allergic reactions are produced locally in specific tissues of a body part, such as nose, eyes or skin. In anaphylactic shock (or anaphylaxis), an allergic reaction does not involve the entire body and usually occurs in a few minutes after contact with a particular allergen. Symptoms of anaphylactic shock (or anaphylaxis) may include:
If you have an anaphylactic shock (or anaphylaxis), you need emergency treatment, usually an injection of adrenaline.
Who is affected by allergy?
The reason that triggers an allergic response is not clear. Some experts believe it may be associated with pollution. Another theory is that allergies are caused by living in an environment that is too clean and free of germs, which would reduce the number of germs that the immune system is able to cope with. This can cause an overreaction when you come into contact with harmless substances. Some people are more likely to develop the hereditary allergy. If this possibility exists, it is called atopic allergy or suffering from atopy. Atopic individuals are more likely to develop allergies because their body produces more IgE antibody than normal. Environmental factors also play a role in the development of allergic disorders. The exact role of the environment is unknown, but studies have shown that a number of factors appear to increase the chance that a child will develop an atopy, such as:
Boys are much more likely to develop an atopy than girls. They are also more prone to be born with a weight below normal. The reasons for this are also unclear.
What are the causes of allergy?
An allergy develops when the immune system reacts to allergens, and they are considered to be harmful, as if they were an infection. There is a type of antibody (protein that fights viruses and infections) called immunoglobulin E (IgE), that fights the allergen. When the body comes into contact with the allergen, IgE antibodies are released causing a chemical production. Together, all these things cause the symptoms of allergic reaction. One of the chemicals involved in an allergic reaction is histamine, which causes:
An allergen is any substance that causes a stronger reaction of the immune system by producing antibodies against them. There are thousands of allergens, but the most common are the following:
How to treat allergies?
Where possible, the best way to defend against an allergy is to avoid contact with the allergen causing the reaction.
Drugs
Medications cannot cure allergies, but can be used to treat common symptoms such as a runny nose, itching and sneezing. Many treatments are available as OTC drugs, but before buying them, you should always seek the advice from your doctor or pharmacist.
Antihistamines
Antihistamines treat allergies by blocking the action of histamine, the hormone that body releases when it thinks an allergen has attacked the body. Antihistamines are in the form of pills, creams or liquids or eye drops and nasal spray. The nasal spray may be used to reduce swelling and irritation of the nose and eye drops are used to help relieve pain and itching of the eyes. Spray drops and eye drops are only available for adults, so you should always consult your doctor before buying drugs, especially if children are involved.
Decongestants
Decongestants help bring relief for a blocked nose, which is often caused by hay fever, an allergy to dust mites or an allergy to pets. Decongestants are available in different forms such as tablets, capsules, nasal spray or liquid.
Leukotriene antagonists
The tablets are leukotriene antagonists that block the effects of leukotrienes, a chemical released during an allergic reaction that causes inflammation (swelling) of the respiratory tract. Leukotriene antagonists are used to treat asthma when other treatments have failed.
Hyposensitization (immunotherapy)
Another form of treatment for allergies is the hyposensitization, also known as immunotherapy. The hyposensitization acts gradually introducing increasing amounts of allergen into the body to make it less sensitive to it. Allergens are usually given by injection at intervals of one week or less and the doses of the allergen are going to increase. Upon reaching the maintenance dose, a dose that is effective in reducing the usual allergic reaction, continue with injections every few weeks for at least two years. The hyposensitization is usually recommended for the treatment of various allergies (hay fever or allergy to pets), that have not had improvements with other treatments and for specific allergies , such as the stings of wasps and bees. This treatment should only be administered under the supervision of a physician because there is a risk involved of severe allergic reactions.
The treatment of anaphylaxis
If someone had an anaphylactic shock (or anaphylaxis) that required medical emergency treatment with adrenaline injection, that person is a subject to the possibility of triggering an anaphylactic shock again, then he or she must have a self-injection kit of adrenaline. It is an easy-to-use syringe that you should always carry.
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