What is sensitization?
Sensitization is a process where the immune system develops a reaction to a substance that is not normally harmful to the body, such as a food, pollen or an animal such as a cat or dog. When the immune system becomes sensitized to a substance, the person is often called "sensitized" to that substance.
The immune system produces antibodies
Sensitization occurs when the immune system is exposed to a substance, or allergen, that the body perceives as harmful or foreign. The immune system produces antibodies against the allergen, which can lead to allergic symptoms on the next exposure to the allergen. The more a person is exposed to the allergen, the more likely it is that the person will become sensitized to the substance.
Sensitization can be investigated by testing for antibodies against the allergen in the blood or by performing skin tests where small amounts of the allergen are applied to the skin and the reaction is measured. However, sensitization does not always have to lead to allergic symptoms. Many people can be sensitized to an allergen without developing allergic reactions when exposed to the substance.
Measurement of IgE levels – part of an allergy investigation
In a blood test for allergy testing, the amount of immunoglobulin E (IgE) antibodies in the blood is measured. Measuring IgE levels in the blood can indicate whether a person has an overreaction to a specific allergen. The higher the level of IgE in the blood, the greater the probability that the person is allergic to the specific allergen.
Allergy testing through blood tests can be used as part of the investigation of allergies and to monitor the effectiveness of allergy treatments.