What is allergy?

Allergy is when your immune system reacts to allergens — substances in the environment that cause allergy. You can be exposed to allergens in different ways, including:

• inhaling (airborne allergens)
• eating (food allergens)
• injecting (such as medicines or insect stings)

What are common airborne allergens?

Substances that cause allergy symptoms are called allergens. Airborne allergens are those carried by air. They include:

• pollen — typically from grasses, flowers and trees
• house dust — which includes insect debris, dust mites, dust mite droppings and dead skin
• animal dander — which is particles of dead skin, hair or feathers
• mould spores (tiny particles carried in the air)
• cigarette smoke

What are the symptoms of airborne allergies?

When breathed in, airborne allergens can trigger symptoms in people who are allergic to them. Symptoms include:

• frequent bouts of sneezing
• a runny nose
• blocked nose (one or both nostrils)
• itchy ears, nose, throat and roof of the mouth
• red, itchy, swollen or watery eyes
• headaches

These symptoms can be caused by many other conditions, including the common cold and COVID-19. If they persist longer than a few weeks, or you notice them at particular times of year, they may be due to allergy.

If hay fever is not treated properly, it can:

• make asthma harder to control and can lead to sinus infections
• affect children’s concentration and school work
• lead to bad breath or a husky voice
• cause more frequent eye infections

Other substances that are irritating for some people, such as perfumes and cold air, can make allergy and asthma symptoms worse.

People who have hay fever all year round are often allergic to dust mites, animal fur and/or mould spores. If they have allergy symptoms only during spring, it is usually caused by pollen.

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

How are airborne allergies diagnosed?

Sometimes, the cause of allergy symptoms is obvious, for example, if your child is allergic to a pet. Other times, your child’s doctor may need to help you identify what’s causing the allergy.

The doctor will talk to you and/or your child and ask questions about:

• the timing of symptoms
• the types of plants that grow near your home, school or work
• if you’ve had exposure to any animals or pets
• if you / your child feels any better when away from home

If your child has severe allergic rhinitis, they may need to be referred to a clinical immunology / allergy specialist for further assessment.

The specialist may suggest that your child has allergy tests (such as skin prick or blood tests) to identify the cause.

When should I see my doctor?

Sometimes, the cause of your child’s symptoms is obvious, and you can take steps yourself to reduce their exposure to their allergens.

You should see your doctor if you can’t easily identify the cause of your child’s symptoms.

You should also see your doctor if your child’s symptoms are severe, or if they have asthma. There are medicines or treatments that can help.

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

How are airborne allergies treated?

Although allergies and hay fever cannot be cured, there are some things you can do to reduce the symptoms and give your child some relief.

The best treatment is to identify the cause and then try to prevent or minimise your child’s contact with it.

During the pollen season, it can help to keep your child indoors in the mornings and avoid parks (and any grassy areas) where possible. Removing any plants in your home and yard that cause the allergy can also reduce symptoms.

Here are some other ways to reduce symptoms:

• Keep your home and car free of cigarette smoke.
• Clean your house thoroughly and regularly to reduce house dust and dander.
• Wash bedding, soft toys and soft furnishings regularly.
• Keep your pet outside, or rehome it, if the allergy is severe.
• Remove sources of mould and dampness.
• Lower the humidity in your house to reduce mould; dehumidifiers can help.

Your doctor may also suggest medicines to help relieve your child’s symptoms. These include non-sedating antihistamines and nasal sprays (which may be useful for older children).

Another option for severe allergic symptoms is specific allergen immunotherapy. It is a long-term treatment. Your doctor will be able to advise whether this treatment is suitable for your child.

Resources and support

• The Australasian Society of Clinical Immunology and Allergy has information about airborne allergens and how to minimise allergy symptoms.
• Visit Allergy & Anaphylaxis Australia to read more about allergic rhinitis (hay fever).
• If your child is allergic to pollen, visit Asthma Australia to find the best pollen App in your state or territory, and tips to stay safe in pollen season.