It is so common today to hear that someone has some kind of allergy, maybe even you have some. For instance, it can be an allergy to some food. Or to dust or pollen. Or an allergy to a sting of an insect. Actually, it can be a lot around us, that can cause an allergic reaction. But do you know what really are allergies? Let's find out in this lesson.
Allergies are also known as allergy diseases. These conditions are caused by hypersensitivity of the immune system to typically harmless substances in the environment. These substances are typically seen as harmless by the immune system in nonallergic individuals and do not cause a response in them. But in allergic people, they are seen as foreign, and the immune system will generate a response to them. The immune system cells will release certain chemicals, such as histamine, and that will lead to allergy signs and symptoms, like sneezing, some rash, hives, and many more. Allergy development is due to both genetic and environmental factors.
Allergies can develop at any age, but most food allergies begin at a young age, and many of them are outgrown. Environmental allergies can develop at any time. It is not fully understood why one person develops allergies and another does not. The severity of allergies varies from person to person and can range from minor irritation to anaphylaxis, which is a potentially life-threatening emergency.
The substances that cause allergies are called allergens. The most common allergens are pollen, food, animal protein, mold, some medications, metals, etc. If someone is allergic to any of these substances, their immune system will react (will create antibodies), and allergy symptoms will occur. For example, if you have an allergy to dust mites, your immune system identifies dust mites as an invader or allergen. The immune system will react by releasing chemicals, which will cause symptoms and signs of allergy to occur, like runny nose and sneezing. This is a case of inhaled allergy, which are the most common types of allergy. Ingested allergies are caused when an offending allergen is eaten. And there is one more group of allergies, called contact allergies, that occur when a substance (allergen) comes in contact with a person's skin.
Allergic rhinitis, also known as hay fever, is a type of inflammation in the nose which occurs when the immune system overreacts to allergens in the air. The nasal allergy is triggered by something we inhale. Common signs and symptoms include:
Skin allergy occurs when the skin comes into direct contact with an allergen. For instance, if you wear some ring, and you are allergic to that metal, on the place of the ring will appear symptoms. This is called contact dermatitis. Signs and symptoms of skin allergy include:
When discussing skin allergies, there is one allergic skin condition, called Atopic dermatitis (eczema). Atopic dermatitis most often occurs where your skin flexes — inside the elbows, behind the knees, and in front of the neck. This condition can cause the skin to:
Food allergy is when we have a reaction to a certain food. This allergy usually comes on suddenly and can be triggered by a small amount of food. It will happen every time when we eat that food. These triggers cause about 90% of food allergies: peanuts, walnuts, almonds, and pecans; fish; shellfish, milk, eggs, soy, wheat. This allergy can be life-threatening. Signs and symptoms from food allergy can be more serious, and include:
We can get allergy from an insect sting. Bees, wasps, hornets, yellow-jackets, and fire ants are the most common stinging insects that cause an allergic reaction. When these insects sting you, they inject a toxic substance called venom. The body can make a reaction to the sting and these signs and symptoms can appear:
A drug allergy is the abnormal reaction of your immune system to a medication. Any medication is capable of inducing a drug allergy. A drug allergy can cause:
Some types of allergies, including allergies to foods and insect stings, can trigger a severe reaction known as anaphylaxis. As a life-threatening medical emergency, anaphylaxis can cause you to go into shock. Signs and symptoms of anaphylaxis include:
For all types of allergies, the best thing is to avoid triggers and the symptoms of allergy are relieved by appropriate medications, like oral antihistamines.
Allergic reactions can be of four types,
Type I, II, and III allergic reactions are called immediate types of allergic reactions because they occur within twenty-four hours of exposure to the allergen.
Type IV allergic reactions are called delayed allergic reactions and typically occur after 24 hours of exposure and are called delayed allergic reactions.
An allergy test is an exam performed by a trained allergy specialist to determine if the body has an allergic reaction to a known substance. Allergy tests involve exposing the person to a very small amount of a particular allergen and recording the reaction.
There are two types of allergy testing, that are considered to be valid:
Tests can determine which particular if an allergy to some substances exist, and doctors can give advice if some measures are needed.
