An allergy is a misguided response of the immune system to contact with certain foreign substance that is usually harmless to most people. Allergy is also referred to as atopy. More than 65% of the population has one or other form of allergy. Most part of our body is prone to allergy and allergic reaction is most commonly seen in eyes, skin, and lungs, but each part shows may different response to the foreign particle. The tendency to get an allergy is usually hereditary but allergy can also be caused by environmental factors.
Almost everything and anything can act as an allergen, the foods you eat, the air you breathe or even the medicines you take can shoot back and cause allergic response. The immune system of our body is set so as it recognizes any foreign particles that may be dangerous for the body but the common things like food, dust and pet hair are not usually recognized as foreign by the immune system. And the body does not produce any immunological responses if it comes in contact with these particles.
In some, the body treats the common environmental particles, food or medicine as foreign substance or allergen and produce inappropriate reactions to destroy it, leading to symptoms which can even harm the person. The immune system tends to fights against the allergens and protects the body by producing antibodies belonging to class of immunoglobulin E (Ig E). This in turn activates the mast cells and the allergy cells of the body, basophil which releases different chemicals including histamine which defends the body and fights against the allergen. The allergic reaction may affect the person's nose, skin, gastrointestinal tracts and eyes. Each time the body comes in contact with the same allergen, similar allergic reactions are triggered.
The allergic reaction can cause different symptoms ranging from very mild ones to serious and life threatening ones. Allergic symptoms can be classified to mild, moderate and severe symptoms.
Mild symptoms do not spread to other part of the body and can be easily treated. The mild symptoms include congestion, watery eyes, rashes and running nose.
Moderate symptoms of allergy can easily spread to other part of the body and cause increasing difficulty and uneasiness. Breathing difficultly and itchiness are considered to be moderate allergic symptoms.
Severe symptoms or anaphylaxis is a life threatening allergic response where the whole body is affected. The allergic response may begin seconds after the contact with the allergen and will very soon progress into a very serious condition. If medical care is not provided at time, it may even lead to death. The symptoms of anaphylaxis include lowering of blood pressure, improper breathing rhythm, dizziness, vomiting, mental imbalance or even loss of consciousness.
The allergies caused by a single allergen may vary between people and the symptoms of the allergic reaction will also vary greatly from one to the next. Some common allergies are pollen allergy, food allergy, medicine allergy and dust allergy. The reaction to each of these substances may be similar but vary in the patients.
Pollen Allergy: Pollen is fine powder-like male gametes which may be present in significantly large quantity in the atmosphere. As it is present in large amount in atmosphere, we are very likely to breath in some pollen. And the protein content in the pollen can cause allergic response in many people. This is a type of seasonal allergy and we get the allergy attack only during the flowering season.
One in seven people are found to be allergic to pollen grains. The pollen allergy can usually be associated with symptoms like stuffy nose, itchy eyes, sneezing, conjunctivitis, allergic shiners (dark circle around the eyes due to restricted blood flow in that region) sore throat and breathing difficulties. Pollen allergy can also cause asthma; at first it will be seasonal and continues attack of pollen allergy can even cause chronic asthma.
Hay fever is an allergic condition caused by abnormal sensitivity to airborne pollen and the condition is associated with cold like symptoms including nasal discharges, itchy and watery eyes, sneezing and stuffy nose. These symptoms are caused due to the reactions caused by pollen in the mucus membranes of upper respiratory tract and the eyes.
Food allergy: People may suffer from allergies to different food items or food proteins. Most allergies to food item begin earlier in life and these allergies may either persist lifelong or may resolve it on its own after a few years. The most common food item causing allergies are milk, egg, shell fish, nuts especially peanut, wheat and soy. Certain fruits like apple, peaches and pears, red meat, corn and rice are also associated with limited cases of allergic reaction.
The symptoms of food allergy can be seen to occur within a few minutes of eating the food to a few hours. The symptom of food allergy includes vomiting, nausea, asthma, eczema, abdominal pain and irritation of throat and mouth. In some cases anaphylaxis and death is found to be associated with food allergy if not treated properly and at the right time.
Medicine allergy: Around 10 to 20 percent of hospitalized patient are seen to suffer from allergic reactions to the prescribed medicines. And one in ten people are allergic to the antibiotic, Penicillin. Skin rashes and blisters are the most common type of symptom associated with medicine allergy. People suffering from medicine allergy can develop kidney and liver failure and can have pneumonia like symptoms, asthma and vasculitis. Medicine allergy can also cause decrease in white blood cells, red blood cells and platelets.
Insect sting: Some people may be allergic to the venom of insect like bees, wasps and bumble bees. The insect stings can even cause death in some rare cases. The symptoms can be localized reactions like itching, redness and swelling. It may also cause delayed reaction that may even weeks after the insect bites. Or it may cause systemic reaction affecting the whole body and anaphylaxis. The systemic reaction includes swelling of glottis and epiglottis and narrowing of the bronchial passage, circulatory problems and breathing difficulties. The delayed reaction includes inflammation of brain, nerves, kidney failure as well as blood clotting disturbances.