Allergy and Immunology
Although they are harmless to most people, allergens are substances that can cause some of us to have an allergic reaction. Common allergens include pollen, moulds, dust mites, pets, insects, foods and medicine.
An allergen extract is a very small amount of an allergen, like pollen for example, and is used to test for allergies.
An allergic reaction is when an allergen is inhaled, swallowed or touches the skin of a person who is allergic to it. It can also occur when an allergen makes its way into the body by piercing the skin, like an injection, insect sting or bite. Allergic reactions can result in mild, moderate or severe symptoms (anaphylaxis).
This is the most severe type of allergic reaction and can be life-threatening. That’s why it should always be treated as a medical emergency. Anaphylaxis is usually caused by foods, insects or medicines. Anaphylaxis is a generalised allergic reaction and so can affect one or more organ systems (eg. Respiratory, cardiovascular, gastrointestinal, cutaneous). Symptoms can include:
- Feeling dizzy or lightheaded which can indicate a drop on blood pressure
- Swelling of the throat causing difficulty breathing
- Wheezing or chest tightness
Asthma can be allergic or non-allergic, and results in inflammation of the airways. The inflammation causes swelling and a build-up of mucus which makes breathing difficult. Asthma can be triggered by exercise, cold air and inhaled allergens like animal dander and moulds.
Commonly known as eczema, atopic dermatitis is a reaction that causes areas of red, swollen, itchy and often weepy skin.
An autoimmune disease is when the immune system defends against normal healthy cells and components of the body.
An immune deficiency is when the immune system is underactive, leaving you vulnerable to infections. It can be inherited, caused by certain medical treatments or as a result of other diseases.
A food allergy is when a person suffers from an allergic reaction to certain foods. Common food allergens are nuts (peanuts and tree nuts), shellfish, fish, wheat, soy, egg and cow’s milk.
Allergic rhinitis is commonly known as hay fever and can be seasonal (usually due to seasonal pollens) or perennial (allergens that are present year-round like dust mites and pets). When these allergens are inhaled the lining of the nose becomes inflamed. Symptoms include sneezing, itchy, runny or blocked nose and itchy, watery eyes.
Hives or urticaria are itchy, raised lumps that can spread over the skin, changing position over hours or days.
Insect Sting Allergy
A person with an insect sting allergy will have an allergic reaction to the venom from an insect sting or bite. It is a normal reaction to experience pain, swelling, and redness at the site of the sting or bite. An allergic reaction can cause swelling and redness further from the sting site and can cause hives, flushing and in rare cases anaphylaxis.