ALLERGY TESTING

Dr. Tony Luke Baby

Consultant Pulmonologist

KIMS Al Shifa Hospital

Avoiding or Minimizing exposure to allergic triggers is an important part of allergy and asthma management. Allergy testing using skin prick tests or blood tests for allergen specific IgE helps your doctor to confirm what substances you are allergic to, so that appropriate advice can be given.

Pathophysiology:

If you have an allergy, your immune system overreacts to a substance you inhaled, touched

or ate. Your immune system controls how your body defends itself. For instance, if you have an  allergy to pollen, your immune system identifies pollen as an invader or allergen. Your

immune system overreacts by producing antibodies called Immunoglobulin E (IgE). These

antibodies travel to cells that release chemicals, causing an allergic reaction.

Why allergy testing is performed:

Allergies affect more than 50 million people living in the USA, according to the American College of Allergy, Asthma, and Immunology. Inhaled allergens are by far the most common type. Seasonal allergies and hay fever, which is an allergic response to pollen, affect more than 40 million Americans. The World Allergy Organization estimates that asthma is responsible for 250,000 deaths annually. These deaths can be avoided with proper allergy care, as asthma is considered an allergic disease process. Allergy testing can determine which particular pollens, molds, or other substances you’re allergic to. You may need medication to treat your allergies. Alternatively, you can try to avoid your allergy triggers.

Types of Allergens:

Allergens are substances that can cause an allergic reaction. There are three primary types of allergens:

Inhaled allergens affect the body when they come in contact with the lungs or membranes of the nostrils or throat. Pollen is the most common inhaled allergen.

Ingested allergens are present in certain foods, such as peanuts, soy, and seafood.

Contact allergens must come in contact with your skin to produce a reaction. An example of a reaction from a contact allergen is the rash and itching caused by poison ivy.

Symptoms which usually prompt an allergist to perform testing include:

• Respiratory: itchy eyes, nose or throat; nasal congestion, runny nose, watery eyes, chest

congestion, cough or wheezing

• Skin: itchiness or eczema

• Abdominal: vomiting or cramping and diarrhea consistently after eating certain foods

• Severe reactions to stinging insect stings (other than swelling at the site of the sting)

• Anaphylaxis : a serious allergic reaction that affects many parts of the body at the same

time

Types of Allergy Testing:

Skin prick testing

Blood tests for allergen specific IgE (formerly known as RAST(RadioAllergoSorbent Test))

Total IgE testing

Eosinophil counts

Patch testing

Oral allergen challenge testing

Skin prick testing

Skin prick testing is the most convenient method of allergy testing. As results are available within 20

minutes, this allows you to discuss the results with your doctor at the time of testing. Skin prick testing

has been shown in clinical studies to improve the accuracy of diagnosis.

Skin prick testing is most commonly performed on the forearm or the back.

TREATMENT:

Once the allergic factor is isolated , it is best to AVOID the allergens you are sensitive to .

Antihistamines & Corticosteroids (depending on the severity of the clinical symptoms) will help

control the allergic cascade initiated within you..

If the allergen identified is specifically unavoidable, the n immunotherapy is advised .

Subcutaneous Immunotherapy (SCIT) :

has been a proven allergy treatment for more than 100 years. They are the only treatment that changes

the immune system and prevents new allergies and asthma from developing.

Sublingual immunotherapy (SLIT) :

Is a newer form of immunotherapy. Instead of injecting an allergen under the skin, small doses are administered under the tongue. There are two types of SLIT – tablets and drops – but the only forms that have currently been approved by the FDA are tablets for ragweed and grass pollen. Most clinical trials and surveys published over at least 20 years show that SLIT is relatively safe and effective for the treatment of rhinitis and asthma caused by allergies to dust mites, grass, ragweed, cat dander, and tree pollens. Evidence is emerging that SLIT may be effective for treating the red, itchy eyes caused by pollen during hay fever season. In addition, it might prove an effective therapy for children with mild eczema and is currently being studied for its potential in treating food allergies.

I am happy to inform about the Availability of Skin Prick Allergy Testing at the

Pulmonary Medicine Department of Kims Al Shifa hospital under My Supervision