Common Indoor And Outdoor Allergens in Children by Dr. Srikanta J T

7 min read

Written by Dr. Srikanta J T

Dr. Srikanta J T

Dr Srikanta J.T is a Interventional Paediatric Pulmonologist based in Bangalore with 12+ years of experience.

His expertise lies in Paediatric Pulmonary Medicine, Paediatric Interventional P More

Common Indoor And Outdoor Allergens in Children

Substances that can cause allergic reactions are specifically called allergens. Allergens exist everywhere, inside the house and in the environment outdoors. They exist in different forms like pollen, dust, insect remains, and molds. When the human body comes in contact with the allergens indoor or outdoor, it involuntarily releases certain antibodies to fight them in children. This can lead to allergic reactions. Occasionally these indoor and outdoor allergens are proven harmful to children who are prone to allergies, especially in kids with allergic asthma and other inherited skin diseases like eczema. In this article, we discuss some common indoor and outdoor allergens in children.

In some children, allergens may cause seasonal or perennial allergic rhinitis. Allergic rhinitis includes a runny or itchy nose, sneezing within a few minutes of inhaling them, itching or irritation inside the nose and the roof of the mouth which may last for a few days or throughout the year. Certain allergies are seasonal and temporary, and they will pass with time. While some allergies caused by both indoor and outdoor allergens are long-lasting, harmful, and may lead to complications in Children. Allergy complications are mostly genetically inherited and require the attention of a doctor.

In This Article

What Are Indoor Allergens?

Allergens that are found inside a house are called indoor allergens and include dust, dust mites, insects, pets, and indoor plants. All pets and pet fur may not necessarily be allergens, but the minute organisms that are present on their fur and saliva can be allergenic. Do we have allergens at home? Yes, it is common to find many allergens in every household. Children who are vulnerable to allergens can be sensitive to such indoor allergens. Household cleaning agents and chemicals can also can allergies in some children.

What Are the Most Common Indoor Allergens in Children?

Most Common Indoor Allergens

Indoor allergies can be harder to avoid and are not seasonal. There is a list of indoor allergens that can trigger allergic reactions in children who are vulnerable to allergens.

1. Dust

Dust is a common complaint in every house. It can be a combination of various substances like pollen from indoor plants, insect remains, pet fur, spider webs at the corners of the roof, and molds that form due to the damp environment. Together this can trigger allergic rhinitis and can last longer than expected in susceptible kids. Household dust can be managed by frequent dusting and vacuuming. Some insect remains which are part of house dust can be airborne and trigger allergies when inhaled.

2. Dust Mites

Dust mites are the minute insects that prefer to shelter in humid environments. These are very small insects that we cannot see with the naked eye. They typically feed on the minute flakes of human dead skin. Dust mites grow in warm and humid temperatures. Maintaining a humidity-free house can help in keeping the dust mites away from your furniture and bedding.

3. Cockroaches

Cockroaches are the most common complaint in every household. Dripping water and wet environments are the reason for the presence of cockroaches at home. Their small remains like the antenna and the other small particles from their fore and hind legs can stay in the air and cause allergies when inhaled. Cockroach waste is also one of the common sources of allergic rhinitis.

4. Fabric Fibres

These are small particles that detach from clothing and can stay in the air for enough time to be inhaled. Such tiny particles can cause itching and irritation inside the nose. Detergent particles present on these fibres can also trigger allergic reactions in children.

5. Animal Waste

Pet waste or animal dander like fur, saliva, and animal waste comes under one of the indoor allergens and can lead to allergic rhinitis. It is important to keep the pets away from your bedding and furniture if your child is prone to allergies.

6. Indoor Plants And Molds

Indoor plants need constant watering, some may or may not need sunlight. Keeping plants in closed rooms and watering them can lead to the growth of molds because of the dampness. Keeping the environment dry and ventilated can help avoid the growth of molds.

[Read : Dog Allergies In Babies]

Indoor Allergy Signs And Symptoms in Children

Indoor Allergy Signs And Symptoms

An allergic reaction is a natural defence of the human body against foreign particles. Seasonal allergies can be common and regress with time, chronic allergies like perennial allergic rhinitis and allergic asthma can be an alarming situation and might need constant care.

Some symptoms of indoor allergies include

  • Runny nose
  • Stuffy nose or nasal congestion
  • Dry cough
  • Irritation or itching inside the nasal passage, inside the throat, and on the roof of the mouth
  • Constant sneezing
  • Wheezing or difficulty breathing
  • Watery eyes

What Are Outdoor Allergens?

Outdoor allergens are substances from the environment that cause allergic reactions. These are seasonal and act as a source of seasonal allergic rhinitis in children vulnerable to allergens. Outdoor allergens are small particles that can float in the air. Inhaling these may lead to adverse reactions in kids who are prone to allergic asthma and other respiratory troubles.

What Are The Most Common Outdoor Allergens in Children?

Most Common Outdoor Allergens in Children

The most common outdoor allergens are from plants, trees, and grass. There are different types of pollen grains, among them only some trigger allergic reactions.

1. Pollen

Pollination is a fertilization process in trees, plants, and weeds. During spring and autumn, the amount of pollen in the air rises to a point where children start to inhale it and this becomes the main source of seasonal allergic rhinitis or hay fever.

It’s not just plants, trees, weeds, and grass that can also produce seasonal pollen for fertilization. Certain trees also release pollen, some throughout the year and some seasonal, which can be the reason for allergies. Some such trees include

  • Coconut tree
  • Eucalyptus tree
  • Papaya tree
  • Castor oil (throughout the year)

All plants give pollen, certain plants like roses have insects to carry them from one plant to another. But other plants release them in the air, which leads to allergies when inhaled.

Weed pollen can also lead to allergic rhinitis. A special weed called ragweed pollen is the main source of triggering allergy when inhaled. Certain particular grass and weeds like congress grass or parthenium hysterophorus, bermudagrass or Cynodon dactylon, and mesquite or Prosopis juliflora weed are also the main triggers for the cause of pollen allergies in children.

2. Molds

These tend to grow on rotten wood, dried leaves, and damp roads. They release their spores into the air, and these spores when inhaled can cause allergic rhinitis.

3. Other Sources

Other causes like bird droppings may also be one of the reasons for outdoor allergies in susceptible children. Study shows that some kids may suffer from allergies due to the viral load present in the air, though this may not be included in one of the outdoor allergens.

Causes of Outdoor Allergies

A human body reacts to a foreign substance by releasing certain antibodies to fight them. Similarly, our body can misinterpret certain substances like pollen released by the environment, to a foreign body and start to react adversely. The body releases “histamines”, and as a result of this many symptoms arise. These kinds of reactions are called allergic reactions which can lead to hay fever or seasonal allergic rhinitis.

Seasonal allergic rhinitis is respiratory trouble caused by outdoor allergens. It is mostly accompanied by sinus infections as there will be a swelling of blood vessels which may lead to infections. These are mostly caused by the pollen released by certain trees, plants, grass, and weeds. Some may be seasonal and some may stay throughout the year.

Outdoor Allergy Signs And Symptoms in Children

Outdoor Allergy Signs And Symptoms

The signs and symptoms of outdoor allergies are

  • Heaviness inside the nasal passage
  • Facial pain due to sinus infection
  • Throat pain or itchy throat
  • Continuous coughing (no sputum) and sneezing
  • Headache (rare)
  • Runny and congested nose.
  • Wheezing and trouble breathing (in allergic asthma patients)

Outdoor allergy symptoms are almost the same as any other allergy. Allergies from outdoor sources are mostly seasonal and may not stay throughout the year. But, certain trees, grass, and weed produce pollen throughout the year which may cause such symptoms in children vulnerable to allergies.

When to Seek Medical Advice?

Though seasonal allergies are normal and may regress with time, it is important to keep track of the symptoms you experience. Hay fever or allergic rhinitis can lead to adverse reactions in some children giving rise to breathlessness and asthma if ignored. Contact your doctor if you experience symptoms for more than two weeks or if they get worse over time.

Incidences of indoor allergens are getting worse in children, partly due to pollution and mostly due to increasing exposure to the external environment. The use of chemicals in cleaning agents and their presence in the environment is also contributing to allergies. If your child is suffering from allergies, it is important to identify the sources of indoor and outdoor allergens so that the  exposure can be minimized in Children.

It is important to remember that allergies cannot be totally prevented. You can work with your doctor to identify the triggers in your child and avoid them. Your paediatrician may also prescribe antihistamines when the allergies get severe. It is important to see the doctor if you find your child’s symptoms worsening.

[Read : How To Protect Your Child From Indoor Air Pollution?]


1. What Could I be Allergic to Inside The House?

There are so many factors that can trigger allergies inside the house. Some of them are dust, dust mites, pet dander, cockroaches, and other insect remains.

2. Why Are My Allergies Worse Indoors?

Since indoor allergies are not seasonal, they tend to worsen as much as you get exposed to them.

3. What Are Outdoor Allergens?

Pollen and molds are the main sources of outdoor allergens, they may be seasonal or year-round.

Read Also: Skin Prick Allergy Test in Children by Dr. Srikanta J T

Dr. Srikanta J T, MBBS, Diploma in Child Health (DCH), Diplomate of National Board(DNB), Fellowship in Pediatric Pulmonology and Sleep Medicine(NUH, Singapore), Training in Interventional Pulmonology
Consultant - Paediatric Interventional Pulmonology, Allergy and Sleep Medicine, ASTER CMI Hospital
10 years of experience

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