Hay fever is usually straight forward to diagnose, based on the patient’s symptoms. However, in some cases, a doctor may refer the patient for allergy testing.
Hay fever usually only needs to be diagnosed if the patient’s symptoms are particularly severe, the symptom pattern is unusual or the patient has experienced the complications associated with hay fever. To help diagnose the condition, a patient may be asked to keep a diary recording when and where exactly they experience symptoms.
A physician may suggest referral to an immunologist for allergy testing in cases where patients are experiencing the symptoms of hay fever all year round (allergic rhinitis) or patients are not responding to treatment and could be experiencing an allergy to substances other than pollen such as dust, mould or animal dander.
The two main tests used to check this are the skin prick test and a blood test. For a skin prick test, an immunologist places the allergen in question on the surface of the patient’s arm and then prick their skin using a needle, so that the allergen is introduced into the bloodstream. If the patients is allergic to that particular allergen, they will start to develop a reaction, with the skin becoming red, swollen and itchy in the area that was pricked.
A skin prick test may not be suitable for patients with skin conditions such as eczema, because they may already have sensitive, red skin that masks the allergic reaction. This test may also not be suitable for people on certain medications such as antihistamines, which prevent allergic reaction to the substance.
In these cases, a blood test can be used instead to confirm whether an allergy is present. A blood sample is taken and tested for the presence of immunoglobulin E (IgE), the antibody produced when someone with hay fever comes into contact with pollen.