An Allergy is the response of the body's Immune System to normally harmless substances such as pollen, various foods, and house dust mite. In normal people, exposure to these substances (Allergens)does not cause any response. In an Allergic patient though, the Immune System identifies them as a threat, and produces a misguided protective response.
Allergies are classified into IgE-mediated and non-IgE-mediated Allergies. In IgE-mediated Allergies, the Immune System produces exaggerated amounts of a distinct class of Antibodies known as IgE-Antibodies that are specific for the particular offending Allergens. These IgE-Antibodies bind to the surface of cells in the body called mast cells, which become ‘IgE-sensitised’ such that these cells can then identify particular Allergens the next time they come in contact with the body. This process is called sensitisation, and at this stage there are no physical symptoms of an Allergy.
Mast cells are present in tissues that are in contact with the external environment, including the skin, nose, eyes, mouth, throat, stomach and gut. The next time that the same Allergen is encountered, the mast cells identify it as an intruder and produce histamine and other chemicals. It is the release of these chemicals from mast cells and their effects on the body, that result in Allergic symptoms. IgE-mediated Allergy may cause a wide spectrum of symptoms depending on the Allergen and the site of the body affected.
In the nose for example, histamine release results in symptoms of runny nose, itchy nose, sneezing (rhinitis),or itchy red eyes (conjunctivitis).
In the skin, symptoms include redness and nettle rash (hives, wheals).
In the breathing tubes Allergies cause wheezing, cough and shortage of breath (asthma), whereas in the gut symptoms such as abdominal discomfort (‘tummy ache’), nausea, vomiting and diarrhoea may occur. Severe Allergies may result in throat swelling, severe asthma and a drop in blood pressure. Some Allergic reactions are also known as anaphylaxis, and can be life-threatening.
The Immune System may also respond to Allergens without the production of the IgE-Antibody. The mechanisms of these so called non-IgE-mediated Allergies are far less well understood and are likely to involve multiple cells that react inappropriately to the presence of an Allergen.
Whereas symptoms of IgE-mediated Allergies occur rapidly and soon after exposure to the Allergen, this may not be the case with non-IgE-mediated Allergies where symptoms may appear much later. In these cases it can be much harder to determine whether the problem is Allergic in nature, and if so, which particular Allergen is causing the problem.
Allergies can affect anyone regardless of age, gender, race or socio-economic status. Generally though, they are more common in children. However, a first-time occurrence can happen at any age or recur after many years of remission. Hormones, stress, smoke, perfume or environmental irritants may also play a role in their development or severity. Allergies have a genetic predisposition and often run in families.
What causes Allergies?
The substance that causes Allergy is called an Allergen. An Allergen is a type of antigen that produces an abnormally vigorous immune response in which the Immune System fights off a perceived threat that would otherwise be harmless to the body.
An Allergen is an antigen capable of stimulating a type-I hypersensitivity reaction in atopic individuals through ImmunoGlobulin E (IgE) responses. Allergens can be found in a variety of sources such as dust mite, pollen, fungal spores, animal epithlium and various kinds of foods suchaspeanuts,nuts,milk, seafood and shellfish are the cause of serious Allergies in many people. Allergens can be inhaled or ingested, or they can enter through the skin. Dust Mites, pollen and molds are common inhaled Allergens.
Did you know that eight types of Food account for about 90 percent of all Allergic reactions?
• Eggs
• Milk
• Peanuts
• Tree nuts
• Fish
• Shellfish
• Wheat
• Soy
Certain seeds, including sesame and mustard seeds (the main ingredient in the condiment mustard), also are common Food Allergy triggers and considered a major Allergen in some countries.
Anaphylaxis
Also called Anaphylactic Shock, this is a severe, often sudden, life-threatening reaction to certain Allergens. Body tissues may swell, including tissues in the throat. Anaphylactic shock is also characterized by a sudden drop in blood pressure. While each person may experience symptoms differently, the following are the most common symptoms of Anaphylactic Shock:
• Itching and hives over most of the body
• Feeling overly warm
• Swelling of the throat and tongue or tightness in throat
• Difficulty breathing or shortness of breath
• Dizziness
• Headache
• Pain or cramps
• Nausea, vomiting or diarrhea
• Shock
• Loss of consciousness
• Feeling light-headed
• Anxiety
• Abnormal heart rate (too fast or too slow)
Anaphylactic Shock can be caused by an Allergic reaction to a drug, food, serum, insect venom, Allergen-extract or chemical. Some people who are aware of their Allergic reactions or Allergens carry an emergency Anaphylaxis Kit that contains injectable epinephrine (a drug that stimulates the adrenal glands and increases the rate and force of the heartbeat).
How does Allergy affect you?
When a harmless substance like dust, mold or pollen is encountered by a personwho is allergic to that substance, the Immune System may overreact by producing Antibodies that attack the Allergen. This can cause wheezing, itching, a runny nose, watery or itchy eyes and other symptoms.
http://acaai.org/allergies/types : use this website’s page if no copyright infringement or create a similar looking page
Types of Allergy
Allergic Rhinitis
ARIA 2012 Classification of Allergic Rhinitis
Co-morbidities due to Allergic Rhinitis
Allergy Treatment Options
Minor allergic reactions can be safely treated at home. Over-the-counter Anti-histamines and Decongestants can ease congestion and breathing problems. These medications are generally available as tablets, eye drops, and nasal sprays.
There are other ways to diminish Allergy symptoms and these are the three types of treatments that can be used in combination.
• AVOIDANCE of the Allergen
• MEDICATION (Anti-histamines)
• IMMUNOTHERAPY (Allergy Shots)
Avoidance of air-borne Allergens all of the time is virtually impossible. Pollen, for example, is present anywhere you go. Moving to another area to avoid Allergies is not a practical approach, plus who knows what you will get exposed to there as well!!However, studies do indicate that Allergen Avoidance is essential to effective treatment of Allergies and Asthma.
You can also use Allergy prevention devices in your home, such as an Air-purifiers, Air Conditioners, covers for pillows and mattresses. These will help reduce the pollen, mold and dust mite load exposure for you. Of course it is important to keep the filters on these devices clean!
ImmunoTherapy Allergy Vaccines) is a series of shots or drops that can expose you to small quantities of Allergens to stimulate your Immune System. The purpose of these shots is to build up your Antibodies, your defense cells. This increase in the number of Antibodies will help your body not overreact when exposed again to these same Allergens.
These three treatment options can be used individually or in combination. There are many over- the-counter medications that do not require a prescription, as well as herbal and home remedies. Your primary care Doctor or an Allergist can help. Tests are available to determine which pollen sources are causing your Allergies and they can assist in determining if a prescription medication or Allergy Shots are a good fit for your treatment.
The Cost of Productivity Losses Associated with Allergic Rhinitis
Increased Absenteeism and reduced Productivity due to Allergies cost US employers more than $250 million in 1998($291.6 million in 2002 dollars). In a study of 5000 employees at 57 Companies, 34% of employees with Allergies said they missed an average of 1-5 days of work per year as a direct result of Allergy symptoms. Further, 82% of those with Allergies reported a 26% loss of effectiveness at work due to Allergy symptoms. Employees were affected an average of 69.9 days annually.
Overall health-care costs for Allergic Rhinitis, which are accelerating at a rate of 12% per year include direct costs i.e., costs related to patient care, and indirect costs, i.e., costs of disease consequences, such as Absenteeism and reduced Productivity at school or work.
Direct costs of a disease can be medical - such as the cost of medications, office visits, emergency room visits, diagnostic testing, home health-care devices, and hospitalizations. Or non-medical, including transportation to and from the health-care provider and the purchase of home aids and services (e.g., special diets, home help).
In addition, there are 'hidden costs' of Allergic Rhinitis, such as those related to its tendency to lead to inflammatory airway diseases and other respiratory complications, and those related to the adverse effects of OTC sedating Anti-histamines and Decongestants used in self-treatment.
