How allergies happen

Allergies happen when your child reacts to something in the environment. The thing that causes the reaction is called an allergen. It might be something like food, dust mites or pollen.

Allergens cause your child’s immune system to release histamine and other substances into his body. This leads to allergy symptoms.

Mild, moderate and even severe allergic reactions are common, but deaths from allergic reactions are rare. Deaths can happen when there’s a delay in giving life-saving medication to the person having the reaction.

Allergic reactions: how quickly do they happen?

An immediate allergic reaction usually happens within minutes or up to 1-2 hours after your child comes into contact with or eats the substance that she’s allergic to.

A delayed allergic reaction usually happens many hours after exposure. It can happen up to several days after your child comes into contact with the substance he’s allergic to.

Mild or moderate allergic reactions: symptoms

If your child is having a mild or moderate allergic reaction, her symptoms might include one or more of the following:

• rash, hives or welts
• swelling of the face, eyes or lips
• tingling or itchy mouth
• eczema, hay fever or asthma – these symptoms might be worse than usual
• diarrhoea, stomach pain or vomiting.

Note that if your child has diarrhoea, stomach pain or vomiting after an insect sting, it means he’s having a severe allergic reaction.

Severe allergic reaction or anaphylaxis: symptoms

A severe allergic reaction is called anaphylaxis. Symptoms might include one or more of the following:

• difficult or noisy breathing
• tongue and throat swelling or tightness
• difficulty talking or a hoarse voice
• a wheeze or persistent cough
• persistent dizziness or fainting
• paleness and floppiness (in young children)
• diarrhoea, stomach pain or vomiting after an insect sting.

Anaphylaxis is a life-threatening allergic reaction and needs urgent medical attention. If your child is having an anaphylactic reaction, first lay her flat. Don’t let her stand or walk around. Next use an adrenaline auto-injector like EpiPen® if one is available. Then call an ambulance – phone 000.

Testing for allergies

If you think your child might have allergies, getting a proper assessment is important.

To start this process, you can talk to your GP, who might refer you to an allergy or immunology specialist for the following tests:

• Skin-prick test: your child’s skin is pricked with a special device that looks a bit like a toothpick and that contains a drop of a specific allergen. If a hive comes up where your child’s skin has been pricked, your child probably has an allergy.
• Blood tests: the serum specific IgE antibody test looks at your child’s blood to see whether he’s sensitive to specific allergens. Your child might have this test if he can’t have skin-prick testing. If your child’s blood has a high amount of antibodies, he probably has an allergy.

You might hear about tests like IgG food antibody testing, Vega testing and hair analysis. These tests haven’t been scientifically proven as allergy tests. Tests and treatments that are backed up by science are most likely to work, be worth your time, money and energy, and be safe for your child.

Treatment for mild to moderate allergic reactions

The way you treat an allergic reaction depends on how severe the reaction is.

Antihistamines
Giving your child a dose of antihistamine (in tablet or syrup form) is appropriate if your child is having a mild to moderate allergic reaction, including a skin rash, tingling mouth or swelling.

In fact, having some antihistamine syrup in your home first aid kit or in your bag is a good idea – this way it’s handy when you need it. You don’t need a prescription to buy antihistamines in Australia.

It’s best to use antihistamine that won’t make your child sleepy. Your pharmacist or GP can advise you on the most appropriate brand for your child.

Other treatments for allergies
Depending on the kind of allergic reaction your child has, she might need other treatments. For example:

• If your child has eczema, he might need corticosteroid ointments.
• If your child has hay fever, she might need corticosteroid nose sprays.
• If your child has asthma, he might need an inhaler like Ventolin® or Asmol®.

Your doctor can also give your child an ASCIA (Australasian Society of Clinical Immunology and Allergy) action plan. The action plan usually includes important information on how to manage allergic reactions and which medications your child should use.

Children who have persistent and troublesome allergies to insect stings, house dust mites and grass pollen might have immunotherapy to reduce their symptoms. Immunotherapy isn’t currently used for food allergies in Australia.

If your child has a food or insect sting allergy, it’s especially important to maintain good control of her asthma. If your child has a severe asthma attack, call an ambulance immediately.

Treatment for anaphylaxis

Children at significant risk of anaphylaxis are often prescribed adrenaline auto-injectors – for example, EpiPen®.

If your child is prescribed an adrenaline auto-injector, it’s important that both you and your child learn how and when to use it. Your child’s adrenaline auto-injector should be easy to reach at all times. You can also teach others – family, friends, teachers and carers – how to use it.

It’s also a good idea for your child to wear a medical bracelet to let other people know about his particular allergy.

Allergy risk factors

Children who have family members with allergies or allergy problems like asthma, eczema and hay fever are at increased risk of also developing allergies.