Allergy FAQS

An allergic reaction occurs when the immune system reacts to a substance e.g. food, insects or medications (allergen). This is due to production of allergy antibodies called Immunoglobulin E (IgE) to that particular substance and, the reaction between allergen and antibody results in allergic reaction.

An allergic reaction can be mild, moderate or severe.
Signs and symptoms of mild to moderate allergic reaction include:

• Swelling of the face, lips, or eyes
• Hives or welts on face/body
• Abdominal pain/vomiting (these symptoms indicates severe allergic reaction in an insect allergy).

Signs and symptoms of severe allergic reaction (anaphylaxis) include one or more of the following:

• Difficult or noisy breathing
• Swelling of the tongue
• Swelling or tightness in the throat
• Difficulty talking or hoarse voice
• Wheeze or persistent cough
• Persistent dizziness or collapse
• Pale and floppy (in young children)

If you eat a food you are allergic to, the symptoms of an allergic reaction usually develop within half an hour to one hour of eating that food. This usually happens within the first few minutes but can be delayed for few hours.

Almost any substance that is eaten (including herbal medicines) can trigger an allergic reaction. The most common foods causing allergic reactions include cow's milk (dairy), egg, wheat, peanut, tree nuts, sesame, soy, fish, and shellfish.

Blood tests and skin prick tests can be performed to look for allergy antibodies to a particular food or environmental allergen that a person may be allergic to. Skin prick tests are recommended as the preferred method. The results need to be interpreted by an Immunologist and Allergist.

Hills Allergy and Specialists Clinic provides assessment and management of food and environmental allergens.

As the name suggests, the skin (usually the arm or leg) is pricked with a sharp object called lancet (a commercially prepared medical instrument). The results are read after 15 minutes. A positive test looks like a “mosquito bite” with an itchy lump in the centre and redness around it. The treating specialist will interpret the results in conjunction with the patient's history and advise further management. A copy of the results is provided to the parents/carers on the day.

There is no strict age limit but the skin reactions are often diminished in very young infants and this can make interpretation of results challenging. Therefore, skin prick tests for children under the age of 2 years should be performed in a specialist practice.

We perform skin prick tests to a wide range of allergens including food (milk, soy, egg, grains, peanuts/tree nuts, fish/shellfish, fruits/vegetables, meats), dust mites, pollen, mould and pets/ animals. We also perform skin prick testing to fresh foods.

The risk of systemic or severe reaction is very rare. Skin prick test is a very safe procedure. The expected reaction on the skin is an area of lump and redness (like a “mosquito bite”). These tests should only be performed by trained and experienced medical staff, in centres with appropriate facilities to treat severe reaction.

A positive food allergy test (skin test or blood test) means that a person's immune system has produced an antibody response to that food. This is called sensitisation if the person has not eaten the food. Sensitisation to a food may not be an allergy, which means that the person can eat the food without any symptoms. Therefore, food allergy diagnosis and management should be confirmed by a clinical immunology/allergy specialist.

If a person has had an allergic reaction to a particular food, followed by a positive skin prick or blood test, this indicates that they are allergic to it.

The food allergy needs to be confirmed by a clinical immunology/allergy specialist, as unnecessary food avoidance in children can potentially affect their growth.

Once the food allergy is confirmed, the food needs to be avoided. The patient needs ASCIA allergy or ASCIA anaphylaxis action plan to manage accidental allergic reactions.

Strict avoidance of confirmed food allergens is one of the key parts in the management of food allergy. Equally important is to know the signs and symptoms of allergic reactions and know what to do when a reaction occurs.

Food challenges are highly specialised supervised procedures performed by health care professionals specialised in the field of allergy. Your child needs to be assessed by a clinical immunology/allergy specialist first to determine their eligibility for this procedure.

During a supervised food challenge, the patient is given small and incremental amounts of a food in a medical specialist clinic. The patient is continuously monitored for signs of an allergic reaction to the food being challenged. If there is no reaction, the patient is advised to continue the food in their diet regularly. But if there is an allergic reaction, the patient is advised to continue avoiding that particular food. The challenges in our clinic are performed by experienced staff and supervised by a clinical immunology/allergy specialist.

Most food challenges take a minimum of 4-6 hours and this includes 2-3 hours to eat the required doses of food, followed by 1-2 hours of observation.

For further information, please contact our clinic.

Please call our office to discuss this. Your child will need to be assessed by an Allergist and Immunologist to determine their eligibility for a food challenge.

A number of medications can affect the skin prick test results and must be stopped before the appointment.

Stop the medications containing antihistamines 3 days before appointment including:

• Commonly used medications: Aerius, Claratyne, Zyrtec, Telfast, Lorapaed, Dimetapp, Demazin, Cordral, Phenergan, Polaramine
• Nose sprays containing antihistamines (Ryaltris, Dymista, Zyrtec)
• Steroid creams

The following medications DO NOT interfere with skin prick tests, therefore, can be continued:

• Asthma medications: Ventolin, Flixotide, Seretide, Singulair
• Steroid nose sprays (Nasonex, Rhinocort)

Please refer to the table of medications in our services section (Download PDF) if your child is on regular medications. If you are not sure, email us the list all the medications your child is taking 3 days prior to the appointment.

Food protein-induced enterocolitis syndrome (FPIES) is an adverse food reaction involving the immune system causing inflammation of the small and large intestines. It mainly affects infants and young children.

A typical FPIES reaction begins with profuse vomiting around 1 to 4 hours (usually at 2 hours) after eating a food that has been recently introduced into the diet, often followed by diarrhoea which can last for several days. In the most severe FPIES reactions, vomiting and diarrhoea can cause serious dehydration. The child may become pale, floppy, and cold to touch (these are the signs of severe reaction).

The most common FPIES triggers are rice, cow's milk (dairy) and soy. However, almost any food can cause an FPIES reaction, including cereals such as rice, oats, eggs, legumes and meats such as chicken and seafood.

Children with FPIES can have poor growth if they continue to ingest trigger food/s. Avoidance of the trigger food/s is currently the only effective treatment option. However, most children will outgrow their FPIES in the preschool years and this is usually determined by a supervised food challenge (for more information regarding food challenge, please refer to what is a food challenge question)

Allergic rhinitis (commonly known as hay Fever) affects around 18% (roughly 1 in 5 people) children and adults in Australia and New Zealand. Despite its name, this condition does not cause fevers. It is an allergic condition caused by the nose and/or eyes coming into contact with allergens in the environment, such as pollens (grasses, weeds or trees), dust mites, moulds and animal dander.

Symptoms of hay fever include runny/itchy/congested nose, sneezing and itchy/watery eyes. The symptoms range from mild/moderate to severe and can affect day to day functioning, sleep disturbance, daytime tiredness, headaches, poor concentration, or recurrent ear/sinus infections.

Hills Allergy & Specialists Clinic provides assessment and management including allergen immunotherapy for environmental allergens.

Allergen immunotherapy (AIT), also known as desensitisation, switches off the allergy by retraining the immune system. It involves introducing small doses of allergen extracts, by injections, sublingual tablets, sprays or drops. AIT treatment is given over a period of time, usually 3 to 5 years.

Eczema (also called atopic dermatitis) is chronic allergic skin condition causing red, inflamed and itchy skin. It usually starts in the first year of life and is most common in babies but can affect children of all ages.