An immune response describes the way your body handles and protects itself against foreign or harmful substances or bacteria. When you experience an allergy, this is an extreme response of your immune system to a foreign substance known as an allergen. The word allergy can be used to describe the negative reaction your body has to an allergen, and it’s important to note that most allergens are not actually harmful to your body. In fact, most allergens have no effect whatsoever on people who do not have allergies.
Allergies and histamines
If a person has allergies, their immune system may be oversensitive towards these allergens and will immediately release histamines if it senses the presence of the allergen. Histamines are a type of chemical which help the body fight off allergens.
The most commonly known allergens may include food, pollen, dust, drugs, insect bites, mould and pet dander.
When histamines are released by the immune system, they can cause allergy symptoms including
- Breathing problems like shortness of breath, wheezing or coughing
- Diarrhoea or stomach cramps
- Itching, burning or teary eyes
- Itching nose, mouth, skin or throat
- Runny nose
- Skin rashes or hives
Allergies are quite common amongst both men and women today and can occur as a result of inherited genes or environmental factors, such as changing seasons for example. The type or symptom of the allergy you experience will also depend on the part of your body the allergen touches.
For example, a food allergy is likely to cause symptoms such as vomiting, diarrhoea, nausea, abdominal pain or cramps. An inhaled allergy is likely to cause symptoms such as a stuffy or itchy nose, a scratchy throat, coughing or wheezing and excess mucus.
Signs and tests for an allergy
If you think you may be experiencing an allergy or have a negative reaction to something you ate or inhaled, it’s advisable to take an allergy test as soon as possible. In some cases, the symptoms you are experiencing may not be caused by an allergen and in order to determine this, an allergy test is required. An example of this is food poisoning – you may have eaten something that doesn’t agree with you or has expired and gotten food poisoning as a result, but you may think you are experiencing an allergic reaction as the symptoms of food poisoning are quite similar to food allergies. In another example, in some cases medications such as aspirin may cause a non-allergic rash or a bacterial infection may cause a runny nose or cough.
The most common method of allergy testing is finger prick testing. This is where the fingertip or skin is minutely pricked by a small needle or lancet, just enough so to draw a small amount of sample blood. The sample of blood is then analysed by a laboratory to determine whether an allergy exists.
Another common allergy testing method is skin testing, which involves simply placing a small amount of the alleged allergen on the skin and pricking the skin over the allergen. If any swelling or a rash occurs, the test is deemed to be positive for that allergen.
Other types of allergy tests include patch testing, intradermal testing or complete blood count (CBC) testing. In some instances, your doctor may also advise you to simply use the “exception method”, which involves removing certain foods for example from your diet, although form of testing may be quite lengthy.