FAQ

ALLERGY TEST

  • The procedure involves the placement of a small drop of the allergen on the skin (usually the patient’s forearm). A specialist nurse will then prick the skin gently using a small lancet.
  • In allergic individuals, this will elicit a localised wheal and flare response after 10-15minutes. Some patients experience localised itching, but any reaction generally disappears within 30 minutes. Ordinarily, 10 to 16 individual tests will be conducted in one visit.
  • Two control tests are run simultaneously. The negative control (salt water) must not produce a response whereas the positive control should produce a wheal and flare.
  • Negative control involves pricking a drop of salt-water on the skin to ensure that the skin is not overly reactive. In some patients, the negative test will come up positive to every single skin test simply because they have sensitive skin.
  • Positive control: a small drop of histamine solution is placed on the skin to determine that the skin has the capacity to react and produce a wheal or flare response. Antihistamine medication will prevent the skin from reacting to the positive control and other allergic tests which is why antihistamine medications must be stopped before the visit.

  • When a person presents with symptoms suggestive of allergy, tests can confirm or rule out causes. There are three medically accepted tests, which can be helpful to evaluate a patient who may have an They are the skin prick tests (SPT), blood tests and challenge testing. However, the history of symptoms is very important and needs to be considered when interpreting any of these tests.
  • Blood tests and skin prick tests are methods that detect IgE antibodies (these are the allergic antibodies). Blood testing for IgE antibodies (also known as RAST testing) measures the levels of allergic antibodies directly in the blood. A positive skin test indicates the presence of IgE antibodies in the skin indirectly. Both methods complement each other and are often used together to help diagnose allergies definitively. There are, however, certain circumstances where skin testing is more suitable than blood testing and vice versa.
  • All results will be discussed and interpreted by Professor Lack.

  • We commonly test for food allergens. It is important, however, to understand that not all food allergens are safe to be tested at the same time in some patients. Therefore, two visits and two separate skin prick tests may be needed to ensure the safety of the patient.
  • Foods we routinely test include; egg white, cow’s milk, peanut, sesame, codfish, wheat, soy and kiwi. We also frequently test for tree nuts (including but not limited to cashew, almond and hazelnut).
  • If you wish to test for fish, shellfish and fruits, we ask you to bring small pieces of individual fish, shellfish and fruits to the clinic. It is more accurate to use the fresh food and we cannot store fresh food in clinic. Please bring each sample in a small container or ziplock bag to prevent cross-contamination and bring a piece of the food in a raw and a cooked form (with no oils or spices added).
  • Respiratory allergies (those that cause hay fever and asthma) typically include house dust mites, cats, dogs, horses, moulds, grass, weeds and tree pollens.
  • Drug allergy testing is more limited. Please bring the medication you are concerned about to the appointment and discuss testing with the nurse or Professor Lack.

  • The short answer is that both methods in conjunction give the most comprehensive diagnosis. An allergy can only be fully diagnosed based on the results of a combined skin prick test and blood test.

  • Food allergies can be detected in the first 6 months of life. There is
    no lower age limit to detect food allergies. Skin Prick Testing is available from 10
    weeks of age.
  • Allergy testing is an effective and decisive method for identifying symptoms in
    Due to the size of infants, however, the number of tests performed is
    limited to a certain number.

  • Skin prick tests are not painful. Young infants are not bothered by the actual
    testing, but may dislike having their arm kept still for the test duration (about 5
    minutes). Older children may be fearful of the tests and the allergy nurse will be
    very reassuring and explain to them that the test is not painful.
  • Allergy tests are safe and do not cause severe allergic reactions or anaphylaxis.
    If a large local reaction causes severe itching, antihistamine syrup is offered
    immediately which rapidly relieves discomfort. On rare occasions, symptoms
    such as a runny nose and/or eyes will occur. Both of which are also easily treated by antihistamine.
  • Some patients may require blood tests. This procedure is performed by an
    experienced phlebotomist. To ease the discomfort of taking blood, we can apply
    surface anaesthetic (‘numbing cream’) prior to the test.
  • Taking blood is extremely safe but may leave a small bruise.
  • Please comfort or distract your child during the procedure to ensure that they
    remain as calm as possible.

  • Supervised Feeds are conducted safely in clinic, they are the definitive method to prove whether or not that patients have outgrown their allergy . Prior to the feed, a full examination of the patient’s Skin Prick and Blood Tests will be undertaken. Successful completion of the Supervised Feed, without any reaction, deems the patient no longer allergic and they are subsequently encouraged to continue eating that food weekly in order to maintain the level of tolerance.
    Supervised Feeds are closely monitored and observed by the Allergy Nurse Specialist, who is highly trained in the recognition and treatment of potential reactions. Additionally, all patients will be briefed by Professor Lack in appointments preceding the test. Please be prepared to be at the clinic for up to four hours after the administration of the feed. Patients must not take antihistamines for five days prior to your Supervised Feed appointment. Furthermore, steroid creams must not be used on the area designated for
    Skin Prick Testing (inner arms or upper legs). Patients are required to bring their own lunch. Eating is permitted approximately one hour after the final dose of the Supervised Feed.
  • [NOTE: THIS IS REPEATED COPY FROM THE SKIN PRICK TESTING, IS IT ALSO SUPPOSED TO BE HERE??]:
    The procedure involves the placement of a small drop of the allergen on the skin
    (usually the patient’s forearm). A specialist nurse will then prick the skin gently
    using a small lancet.
  • In allergic individuals, this will elicit a localised wheal and flare response after 10
    to 15 minutes. Some patients experience localised itching, but any reaction
    generally disappears within 30 minutes. Usually, 10 to 16 individual tests would
    be done in one visit.
  • Two control tests are always run thus in order to properly interpret skin tests. The
    negative control (salt water) must not produce a response whereas the positive
    control should produce a wheal and flare.
  • Negative control involves pricking a drop of salt-water on the skin to ensure that
    the skin is not overly reactive; for example, some patients will come up positive to
    every single skin test because they have sensitive skin.
  • Positive control: a small drop of histamine solution is placed on the skin to
    determine that the skin has the capacity to react and produce a wheal or flare
    Antihistamine medication will prevent the skin from reacting to the
    positive control and other allergic tests which is why antihistamine medications
    must be stopped before the visit.

  • The procedure involves the placement of a small drop of the allergen on the skin (usually the patient’s forearm), then a specialist nurse will prick the skin gently using a small lancet.
  • In allergic individuals, this will elicit a localised wheal and flare response after 10 to 15 minutes. Some patients experience localised itching, but any reaction generally disappears within 30 minutes. Usually, 10 to 16 individual tests would be done in one visit.
  • Two control tests are always run thus in order to properly interpret skin tests. The negative control (salt water) must not produce a response whereas the positive control should produce a wheal and flare.
  • Negative control involves pricking a drop of salt-water on the skin to ensure that the skin is not overly reactive; for example, some patients will come up positive to every single skin test because they have sensitive skin.
  • Positive control: a small drop of histamine solution is placed on the skin to determine that the skin has the capacity to react and produce a wheal or flare response. Antihistamine medication will prevent the skin from reacting to the positive control and other allergic tests which is why antihistamine medications must be stopped before the visit.

  • When a person presents with symptoms suggestive of allergy, then tests can either narrow down or rule out other causes. There are three medically accepted tests, which can be helpful to evaluate a patient who may have allergy. They are the skin prick tests (SPT)blood tests and challenge testing. However, the history of symptoms is very important and this needs to be taken into account when any of these tests are interpreted.
  • Blood tests and skin prick tests are methods that detect IgE antibodies (these are the allergic antibodies). Blood testing for IgE antibodies (also known as RAST testing) measures the levels of allergic antibodies directly in the blood. A positive skin test indicates indirectly the presence of IgE antibodies in the skin. Both methods complement each other and are often used together to help diagnose allergies. There are however some circumstances where skin testing is more suitable than blood testing and vice versa.
  • All results should be discussed and interpreted by Professor Lack.

  • We commonly test for food allergens, however it is important to understand that not all food allergens are safe to be tested at the same time in some patients, meaning that two visits and separate skin prick tests will be needed. This is for your or your childs’ safety.
  • Foods we routinely test include: egg white, cow’s milk, peanut, sesame, codfish, wheat, soy and kiwi. We also frequently test for tree nuts (including but not limited to cashew, almond and hazelnut).
  • If you wish to test for fish, shellfish and fruits we ask you to bring small pieces of individual fish, shellfish and fruits to the clinic, as it is more accurate using the fresh food. Please bring each sample in a small container/ ziplock bag to prevent cross contamination and bring a piece of the food in a raw and a cooked form (with no oils or spices added)
  • Respiratory allergies (those that cause hay fever and asthma) typically include house dust mites, cat, dog, horse, moulds, grass, weeds and tree pollens.
  • Drug allergy testing is more limited. Please bring the medication you are concerned about to the appointment and discuss testing with the nurse or Professor Lack.

  • The short answer is that both complement each other and an allergy can only be fully diagnosed based on the results of combined skin prick testing and blood results.

DISEASE DEFINITION

  • An allergy is an overreaction of the body’s defence system (the immune system) to one or more substances, such as food proteins or pollen, which are normally innocuous to most people. These substances are known as allergens.
  • In people with an allergy, the immune system treats these allergens as intruders and attacks them, resulting in the production of antibodies called Immunoglobulin E (IgE). These antibodies bind to specialised cells (mast cells and basophils) that release substances into the body to defend against the allergen causing an immediate allergic reaction.
  • This reaction usually causes symptoms in the nose, eyes, lungs, throat, sinuses, ears, cardiovascular system, skin or stomach. A subsequent exposure to that same substance will elicit this allergic response again.

  • The “Allergic March” is a term first coined by Professor Lack and describes how allergic diseases progress throughout the life of an allergic individual.
  • The process usually begins within the first few months of life with eczema. In 30-50% of these children, eczema is associated with food allergy. Food allergies generally begin to appear within the first three years of a child’s life. As children grow up, the allergic march may progress to the development of rhino-conjunctivitis (hay fever) and/or allergic asthma.
  • This pattern of development of allergic diseases is commonly seen in individuals with a family history of allergy. Frequently, allergic individuals suffer from multiple allergic conditions (eczema, hay fever, food allergies, asthma) which affect their quality of life. For example, a plethora of symptoms varying from itchy skin to sneezing, snoring, wheezing may result in reduced exercise tolerance, poor sleep and concentration as well as impaired performance at school or work.

GENERAL QUESTIONS

There is no evidence to suggest that avoiding foods during pregnancy or the period of breast-feeding will prevent the development of food allergies in your baby.

It is very important that you have a healthy, well-balanced diet during these important periods.

It is most important that you observe your child for eczema, and keep food proteins away from their skin as these food proteins may cause food allergy (ie. oat based skin creams, coconut oil, avocado oil etc). Please seek early guidance from your paediatrician or allergist if your child has eczema.

You should see an allergist if you or your child suffer from any of the following:

  • Eczema: Patients with eczema should see an allergist if they:
    • Start with eczema in the first six months of life
    • Have eczema resistant to treatment.
    • Have eczema that shows seasonal variations
    • Have eczema and suspect an allergic cause.
  • Allergic Conjunctivitis: You should see an allergist if medications are not controlling your ocular symptoms.
  • Anaphylaxis: If you have had an anaphylactic reaction (very severe allergic reaction) associated with a food or drug or if the trigger has not been identified.
  • Food Allergy: If you have food allergy, you should see an allergist if you have:
    • Multiple food allergies.
    • Co-existent food allergy and asthma
    • If you are on a restricted diet because of food allergy
    • If you are expecting a baby and want counsel on preventing or identifying food allergies
    • If your child is wheezing and you suspect allergic asthma

Your GP can deal with most allergies by prescribing appropriate medicines and advice. In many cases, the GP may decide that you will benefit from being referred to a specialist in allergies. You should look for medical advice if you present with any symptom of an allergic disease. Many people start self-treating their allergies with over-the-counter drugs. However, these medications may have unpleasant side effects, or they may not improve the symptoms.

  • Insect Hypersensitivity: Those individuals who have severe reactions to insect stings or bites.
  • The following patients with asthma should see an allergist:
    • Patients with severe asthma.
    • Patients who have both asthma and food allergy
    • Asthmatic patients who believe allergic triggers are causing their asthma
  • Allergic Rhinitis: A patient with allergic rhinitis (hay fever) should see an allergist if:
    • Medications are not controlling your symptoms.
    • Your quality of life is affected
    • If you are interested on immunotherapy (desensitisation)
  • Sinusitis: Individuals with prolonged or frequent sinus infections.
  • Drug Allergies: Those with a suspected drug allergy who are likely to need that drug again.
  • Urticaria (Hives): Patients with urticaria, hives (nettle rash) should see an allergist if:
    • Urticaria is severe
    • Patient suspects it is caused by a food or a drug
    • Hives lasting 6 weeks or more

TREATMENT

  • Immunotherapy is not homeopathy. Allergy vaccines (under the tongue or injections) are produced from standardised allergens, contain a known amount of the major allergen and they have been evaluated in a large number of clinical studies.
  • Immunotherapy extracts contain high concentrations of the allergen (allergic protein) and the aim is to build up to a high dose. In contrast, homeopathy is unproven in the treatment of allergic diseases, and relies on progressive dilution of the allergen. The “most potent” homeopathic treatments contain no allergen.

  • Allergen immunotherapy is a long-term treatment for allergic rhinoconjunctivitis (hay fever). It helps to reduce allergic symptoms triggered by the exposure to an allergen (e.g. pollen). Paradoxically, the treatment consists of exposing the patient to increasing quantities of the allergenic substance causing the symptoms.
  • Immunotherapy consists of introducing small doses of an allergen that the patient is allergic to – this helps the body to overcome the allergy by teaching the immune system to react to allergens in a different way. Typically, changes in the immune response start after 6 months, and by the end of the three-year treatment schedule, the patient can expect up to 10 years of no symptoms. Immunotherapy may be particularly useful when tablets and/or nasal sprays containing antihistamines or steroids have failed to effectively control the symptoms.
  • Specific immunotherapy is the only treatment that may alter the natural course of allergic diseases whereas other therapies only suppress the symptoms. Allergen immunotherapy reduces symptoms and the need for medications, prevents the development of asthma, reduces the chances of new sensitisations to allergens developing and improves the quality of life.
  • This treatment can be administered under the tongue (sublingually) or by monthly injections under the skin (subcutaneous). Sublingual immunotherapy should be also initiated by a specialist but can then continue to be safely administered at home.