What is allergy?

An allergy is when your immune system reacts to an allergen. An allergen is a substance that exists in the environment that is harmless to most people but makes you have an allergic response.

If your child has allergies, many things inside and outside your home can trigger or worsen their symptoms.

Your child can be exposed to allergens in different ways:

• airborne allergens that you inhale (breathe in)
• food allergens that you are exposed to when you eat certain foods
• insect stings or bites
• medicines that you might swallow or touch

This article is about airborne allergies in your home environment.

What can cause allergies around the home?

Substances that cause allergy symptoms are called allergens. Your child might be allergic to an airborne allergen. These substances are carried in the air and you can inhale them into your lungs.

Airborne allergens include:

• pollen
• house dust mites
• animal dander
• mould spores

Pollens

Pollens from grasses, weeds and some trees can be carried through the air for long distances. They might be in your backyard or local park. These pollens can land in your eyes, nose and airways, and cause hay fever or asthma symptoms.

You can check pollen counts around Australia at Pollen Forecast.

Learn more about pollen allergy.

House dust mites

All kinds of things are in house dust — dirt, dust mites, dead skin, food crumbs, bacteria, fungi and more. Many of these substances are allergenic.

Dust mites are the most common source of allergens in homes, particularly in humid areas. Dust and dust mites collect on every item in your home, including:

• mattresses
• carpets and rugs
• couches
• clothes
• curtains
• soft toys

Pets and animal dander

Allergens are found in animal saliva, sweat, hair, urine (wee) and dander (dead skin flakes). Dander can cause allergic reactions in many people.

You may be more sensitive to one type of animal (such as cats) than another. Any animal can cause an allergic reaction, and even 'hairless' breeds can cause allergies.

Cockroaches

Cockroaches and their droppings are a major allergy trigger.

Mould

Mould can grow anywhere, but it especially likes damp and dark areas. It can be found inside the house, outside and even in foods. Mould grows all year round.

Mould is often found in bathrooms and laundries. It's also likely to grow in evaporative coolers, humidifiers, the refrigerator drip pan and vegetable crisper.

Tiny spores of mould can move through the air.

Irritants

The following irritant substances can also make your child's allergy or asthma symptoms worse:

• cigarette smoke
• air pollution
• perfume
• strong odours
• cold air

What are the symptoms of airborne allergies?

Airborne allergens can cause:

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

These symptoms can also be caused by many other conditions, including the common cold and COVID-19.

If your child's symptoms last for longer than a few weeks, or you notice them at certain times of the year, they may be due to allergy.

Some children can have a very severe allergic reaction called anaphylaxis.

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

When should I see my doctor?

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

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

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

How is the cause of 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 ask questions about:

• your child's symptoms
• the types of plants that grow near your home, school or work
• if your child has contact with any animals or pets
• if your child feels better when away from home
• if you have tried any medicines
• if other family members have asthma or eczema

If your child has hay fever all year round, they may be allergic to dust mites, animal fur or mould spores.

If your child has most symptoms during spring, their allergy is most likely caused by pollen.

If your child has severe allergic rhinitis (hay fever), they may need to be referred to a clinical immunologist (a doctor who specialises in allergies) for further assessment.

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

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 can't be cured, there are some things you can do to reduce the symptoms and give your child some relief.

Ask your doctor or pharmacist for an allergic rhinitis treatment plan.

Self-care at home

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

Here are some ways to reduce exposure to airborne allergens:

• During the pollen season, keep your child indoors in the mornings and avoid parks (and any grassy areas) where possible.
• Check the local pollen forecast before going out.
• Remove any plants in your home and yard that cause allergy.
• Clean your house thoroughly and regularly to reduce house dust and dander.
• Wash bedding, soft toys and soft furnishings regularly.
• Keep your pet outside.
• Remove sources of mould or cockroaches and use a dehumidifier in your house to reduce damp.

Medicines for allergies

Your doctor may suggest medicines to help relieve your child's symptoms. These include non-sedating antihistamines. Nasal sprays may be useful for older children.

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

How else can I prevent allergies around the home?

You can lessen you or your child's allergy symptoms by trying to limit contact with allergy triggers and irritants at home. There are lots of things you can do to help control your child's environment.

Pollen

Although it's hard to avoid pollens completely, here are some suggestions:

• Stay inside during pollen seasons, particularly on windy days or after thunderstorms.
• Keep doors and windows shut in your house and car in the pollen season. If you have an air conditioner in your house or car, use it. If you use a room air conditioner, re-circulate the indoor air rather than pulling air in from outside. Wash or change air filters once a month. Do not use window or attic fans.
• Keep your child away from trees and grasses as much as you can in the pollen season.
• After being outside during allergy season, shower and change clothes right away. Do not keep clothes that have been worn outside in bedrooms because there may be pollen on the clothes.
• Dry clothes in a vented dryer, not outside.
• Wear sunglasses outside.

House dust mites

It's hard to avoid all house dust, but the following ideas might help.

In the bedrooms:

• Avoid clutter particularly in the bedroom. Minimise knick-knacks, wall decorations, curtains, cushions, soft toys and stacks of books or papers.
• Keep the bedroom and wardrobe door closed. Vacuum the wardrobe floor. Store out-of-season clothes in sealed bags.
• Avoid carpets in bedrooms if you can. Vacuum floor coverings often.
• Mattresses and pillows should have allergen-proof covers — you can get these where bed linens are sold.
• Use polyester pillows. Avoid products made of feather, wool, kapok (plant fibre) or foam. Remove sheepskins or woollen underlays.
• Wash blankets, sheets and pillowcases and soft furnishings regularly in very hot water (hotter than 55°C). Cooler water used with detergent and bleach or a product containing tea tree or eucalyptus can also work.
• Tumble dry washing on hot for 10 minutes after it's dry to kill dust mites.

Other ways to avoid house dust include:

• Bare hard floors are best — you can replace carpet with washable, non-skid rugs. If you have carpet, vacuum often and thoroughly, including under the furniture.
• Furnaces should have a dust-filtering system with filters changed monthly. Air ducts should be professionally cleaned at least every 4 to 5 years.
• Use an air cleaner with a high-efficiency particulate air (HEPA) filter or an electrostatic filter — some vacuum cleaners also have HEPA filters.
• Reduce humidity — keep your house dry and well-ventilated. Dehumidifiers or central air conditioners can take moisture out of the air if you live in a humid climate.
• Placing soft toys in the dryer or freezer every week may help.

Pets

• If your child is sensitive to animals, any pets should live outside or stay in just one part of the house.
• Don't let the pet into your child's bedroom.
• Everyone should wash their hands after touching pets.

If someone in your house is very sensitive to a family pet, you face a hard decision. Giving away a family pet is hard, but for some, it may be necessary. You may choose to first speak to family and friends to see if they can provide a loving home, This way you can still stay connected to your beloved family pet. Some organisations can also help you rehome your pet responsibly.

If you do give up your cat or dog, remember to thoroughly clean the house too. It can take many weeks for allergens to be cleared from the house once a pet cat is removed.

Cockroaches

Cockroaches can be hard to get rid of, but here are some tips:

• Keep food in containers with tight lids — never leave food out or uncovered.
• Don't leave out pet food or dirty pet food bowls.
• Vacuum or sweep the floor, wash the dishes, and wipe off countertops and the stove right after meals.
• Take garbage out often.
• Keep food out of bedrooms.
• Fix any water sources that leak.

Mould

Here are some ways to decrease mould growth in the house:

• In the bathroom, clean the tiles, floors, shower curtain, bathtub and base of the shower thoroughly and often. Use a cleaning solution that kills mould, such as diluted bleach or vinegar.
• Ventilate damp areas, like bathrooms. Fix leaks and remove damp rugs.
• Look for areas that become damp after heavy rain and fix any leaks that you find. Clear gutters and blocked underfloor vents.
• Use paint rather than wallpaper on your walls. Some paints discourage the growth of mould but will not kill existing mould.
• Dehumidifiers can help keep mould from growing in damp places such as basements.
• Evaporative coolers, vaporisers and humidifiers with a reservoir are ideal places for mould and bacteria to grow. If you do use one, empty the reservoir daily, clean it with soap and water, and dry it thoroughly.

Greenhouses, compost piles and houseplants are also sources of mould. To reduce mould growth in the garden and in plants:

• Cover the potting soil of houseplants with foil to reduce the spread of mould spores.
• Remove indoor plants.
• Stay away from garden compost or mulch.

Are there any complications of allergies around the home?

If hay fever is not treated properly, it can:

• make asthma harder to control
• lead to sinus infections
• affect your child's concentration and schoolwork
• lead to bad breath or a husky voice
• cause more frequent eye infections
• put you at risk of thunderstorm asthma

Resources and Support

The Australasian Society of Clinical Immunology and Allergy has detailed information about how to minimise airborne allergens in your home.

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.

For information on what to do if you need to rehome a pet, see FOUR PAWS Australia or Pet Rescue.