An allergy test is an investigative procedure used in the diagnosis of an allergy. It involves testing the body for so-called allergens, i.e. substances that are suspected of triggering the allergic symptoms in the body of the person concerned. For example, it is possible to detect both sensitisation, i.e.
a sensitive reaction, and allergy, i.e. to a substance that triggers a specific allergic reaction. Depending on the result, a therapy can then be recommended. – Food
- Insect venoms
- Medicines or also
- Infectious pathogens.
Indications for an allergy test
An allergy test should always be carried out if an allergy is suspected. Therefore, a physician should be consulted if there are any signs, in order to diagnose or exclude a possible allergy. Signs of an allergy initially include a temporal relationship of the symptoms in relation to a certain situation or a certain substance, e.g. the appearance of a skin rash after eating a certain food.
The symptoms can manifest themselves in different parts of the body. If a regular rash appears on the skin, a formation of blisters and itching, a doctor should be consulted. Swelling, i.e. oedema, can also be a possible symptom of an allergy.
In addition, signs such as nausea or vomiting, diarrhoea or constipation should be considered. The eyes may also be affected. Itching or inflammation of the conjunctiva may occur. In addition, itching of the nose and the nasal mucous membranes is common. If one or more of these symptoms are observed, a doctor should be consulted and an allergy test performed.
Procedure of an allergy test
In general, an allergy test uses various methods to determine whether an allergy to a particular substance is present. It can be measured whether there are antibodies against this substance in the body, which are there to fight it, as the body classifies them as “toxic”. This is usually done if there is already a specific suspicion of an allergy, for example to a food.
All that is required is a blood sample, which is then examined in a special laboratory for the said antibodies and other parameters relevant to the severity of the allergy. Another method is to bring the potential allergen (i.e. the allergy-causing substance) into direct contact with the body and to observe or measure the body’s reaction to it. With this type of test, the allergen is usually not known in detail, e.g. in hay fever. The best known test for this is the prick test, in which the allergens are applied to the skin side by side and the reaction is observed after a small incision.
Are there any risks with an allergy test?
Depending on the type of allergy test, it can be associated with different risks. The simple allergy blood test does not usually involve any risks other than those of a normal blood test. However, if an allergy test is carried out in which the body is brought into direct contact with an allergen, a severe allergic reaction may occur in rare cases.
This is very rare, however, because the body is only exposed to a very small amount of an allergen when the test is performed. If such an allergic reaction does occur, in severe cases it can lead to an impairment of the circulation and anaphylactic shock. Therefore, this type of allergy test should always be performed under medical supervision.
In an acute life-threatening situation, the doctor is prepared for possible complications and can detect them quickly and treat them safely by providing an emergency kit. Especially when an allergy test is carried out on suspected food allergy, in some cases a delayed allergic reaction may occur only after the test. Therefore, this type of allergy test should be carried out in a hospital if possible, as the late allergic reaction when carried out in a practice probably only occurs after leaving the practice.