Frequently Asked Questions

Here are the answers to some of the more frequently asked questions about asthma and allergies.

What is Allergy?


The term allergy is used to describe a response within the body, to a substance that is not necessarily harmful in itself, but results in an immune response and a reaction that causes symptoms and disease in a predisposed person. An allergy occurs when the body’s immune system overreacts to normally harmless substances. An allergic person’s immune system believes allergens to be damaging and so produces a special type of antibody (lgE) to attack the invading material. This leads other blood cells to release further chemicals (including histamine) that together cause the symptoms of an allergic reaction.

Allergy is widespread and affects approximately one in four of the population in the UK at some time in their lives.

What are the symptoms of an Allergy?


An allergic reaction may present with a variety of symptoms. The most common are asthma, eczema, hay fever (seasonal rhinitis) or perennial rhinitis where the individual has symptoms all year and food allergy that can sometimes be life-threatening.

What allergens are likely to cause the symptoms?


The most common allergens are:

  • house dust mite
  • tree and grass pollen
  • moulds
  • pets such as cats and dogs.

These may cause symptoms of asthma, eczema or rhinitis.

Food allergy is less common but the main foods most likely to cause problems are milk, eggs, nuts and wheat.

There is a whole range of chemical substances that may cause contact dermatitis (eczema).

Can I take my medication before an allergy test?


If you are having a skin prick test you will need to discontinue your antihistamines 72 hours before testing.

If you are having a patch test for contact dermatitis you should not take oral steroids during the week of the test or for 2 weeks before.

If this is a problem or you are in doubt, you should discuss this with your allergy doctor or nurse before stopping any medication.

How long before I get the results of my allergy test?


Most patients are given a skin prick test on their first appointment and the results are available immediately.

Patients requiring a patch test will be given an appointment for a date when they are available to attend on a Monday, Wednesday and Friday of the same week.

The results will be given to them at the end of that week.

Do I have to be referred by my doctor?


In order to be seen in an NHS allergy clinic, it is necessary to have a referral from your General Practitioner (GP).

Will I see a Dietitian?


If your problem is food related you are likely to be referred to the allergy dietician.

As well as advising you on food exclusions, they will ensure that your diet is nutritionally adequate.

Can I be referred to The David Hide Centre if I do not live on the Isle of Wight?


The Centre accepts referrals from anywhere in the UK as long as there is agreement from the patient’s doctor and health authority.

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