An allergy occurs when your body’s immune system reacts to substances in the environment (‘allergens’) that are normally harmless to most people – for example, food, insect stings or bites, dust mites, animals, pollen and so on.
How allergies happen
An allergic reaction occurs when your child comes into contact with an allergen that she’s allergic to. The allergen enters the body and attaches to antibodies on the surface of specialised white blood cells, which are then triggered to release histamine.
When histamine gets released into the body, it causes the symptoms commonly associated with allergic reactions. Symptoms of mild to moderate allergic reactions include swelling, vomiting, abdominal pain and skin changes such as redness, hives or rash.
Some allergens (for example, food, insect stings and medications) can cause severe allergic reaction (‘anaphylaxis’). In cases of anaphylaxis, your child could have low blood pressure and trouble breathing. Anaphylaxis is life-threatening and requires urgent medical attention.
Not everyone with antibodies to a particular substance will develop allergic symptoms.
Mild, moderate and even severe allergic reactions are common, but deaths from allergic reactions are rare. Deaths are usually caused by a delay in the person receiving life-saving medication.
Spotting an allergic reaction
An allergic reaction usually occurs within minutes or up to two hours after your child comes into contact with or eats the substance that he’s allergic to.
If the allergic reaction is mild or moderate, your child’s symptoms will usually include one or more of the following:
- rash, hives or welts
- swelling of the face, eyes or lips
- tingling mouth
- abdominal pain or vomiting (if this happens after an insect sting, it means your child is having a severe allergic reaction).
In other cases of mild or moderate allergic reactions, allergens such as pollen, animal fur or house dust mite cause symptoms of allergic rhinitis (commonly known as hay fever) and asthma.
If the allergic reaction is severe (‘anaphylaxis’), your child might have any one of the following signs or symptoms:
- difficult or noisy breathing
- swelling of the tongue
- swelling or tightness in the throat
- trouble talking and/or a hoarse voice
- a wheeze or persistent cough
- persistent dizziness or collapse.
Young children might go pale and floppy.
Note that allergies are different from intolerances. Mild to moderate allergic intolerances don’t involve the immune system, but sometimes symptoms of mild or moderate food allergy look similar to those of food intolerances. It’s essential that your child’s food allergy is confirmed by a clinical immunology or allergy specialist.
Our article on recognising food allergies and intolerances has more information.
If your child has asthma as well as an allergy to something, it’s important to control her asthma well.
If you think your child might have an allergy, getting a proper diagnosis is important. To start this process, you can talk to your family doctor, who can refer you to an allergist or immunologist (a medical doctor with specialist training in allergic diseases) for the following tests:
Skin-prick test (SPT): the allergist will put a small amount of the suspected allergen on your child’s skin. The allergist will then prick your child’s skin with a small device that looks a bit like a toothpick. A red lump might come up where the skin has been pricked. Your child’s allergist will talk you through the results of this test.
Blood tests: the RAST (RadioAllergoSorbent test) measures the level of allergen-specific IgE antibody in your child’s blood. This test is done if skin-prick testing can’t be performed because your child has severe eczema or has taken an antihistamine. Your child will need to have some blood taken and tested.
You might see allergy testing methods advertised online and through alternative health providers. Before you put your child through any testing, you might want to think about whether the methods you’re considering are backed up by scientifically validated, reliable evidence. The 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 allergic reactions
The way you treat an allergic reaction isn’t determined by the cause of the reaction. But it will change depending on how severe the reaction is.
Giving your child a dose of antihistamine (in tablet or syrup form) is appropriate if you think your child is having an allergic reaction.
In fact, having some antihistamine syrup in your home’s first aid kit is a good idea – this way it’s handy when you need it. You don’t need a prescription to buy antihistamine syrup in Australia.
Some antihistamines can make your child sleepy, which can look like anaphylaxis in some children and make it hard to tell the difference between the two conditions. It’s best to use antihistamines that won’t make your child sleepy (‘non-sedating’). Your pharmacist or doctor can advise you on the most appropriate brand for your child.
If your child is having difficulty breathing while having an allergic reaction (‘anaphylaxis’), you must call an ambulance immediately – in Australia, phone 000. While you’re waiting for the ambulance, lay your child flat to help keep her blood pressure stable.
Depending on the kind of allergic reaction your child has, he might need other treatments. For example, eczema might be treated with corticosteroid creams or ointments. Asthma treatments include using an inhaler, such as Ventolin or Asmol. If your child has a severe asthma attack, call an ambulance.
Your doctor can give you an action plan to treat your child’s allergic reactions, asthma and eczema. The action plan usually includes important information on the management of allergic reactions and medications to use, as well as how to respond to an allergic reaction.
Children who have had severe reactions to insect stings, house dust mites and grass pollen might undergo immunotherapy to cure them of their allergy. Immunotherapy is currently not available for food allergies.
Dealing with severe allergic reactions
If your child has anaphylaxis, you need to call an ambulance immediately. Your child will be taken to a hospital for urgent medical attention.
If your child is at risk of anaphylaxis, he will often be prescribed an adrenaline auto-injector (for example, Epipen or Anapen) and given an ASCIA (Australasian Society of Clinical Immunology and Allergy) Action Plan.
Once you’re home again, you’ll need to see a specialist allergy doctor. You can work with the specialist to create a written action plan to help handle any future allergic reactions. If your child is prescribed an adrenaline auto-injector, it’s important that both you and your child (when he’s able to) learn how to use it. It’s also usually a good idea for your child to wear a medical bracelet that lets people know about his particular allergy.
It’s important that your child always has his adrenaline auto-injector with him and that any person caring for your child is able to recognise a severe allergic reaction and can use the adrenaline autoinjector. Having an adrenaline auto-injector trainer device allows you to practise using the auto-injector. You can also teach others – family, friends, teachers and carers – how to use it.