Mouth breathing may occur when nasal passages are blocked by allergies or inflammation. Learn why this happens and how restoring nasal airflow improves breathing.
Mouth breathing occurs when someone breathes primarily through their mouth rather than their nose. While it’s common during exercise or temporary nasal congestion, chronic mouth breathing can be a sign of an underlying health issue and may lead to ongoing problems if left unaddressed.
Allergic Rhinitis (Hay Fever)
Allergic rhinitis — often called hay fever — is a very common allergic condition in Australia that causes inflammation of the nasal passages in response to environmental triggers like pollen, dust mites, mould spores or pet dander.
Typical symptoms include:
When the nose becomes congested due to allergic inflammation, air can’t easily pass through the nasal passages. If this blockage is significant or persistent, the body compensates by switching to mouth breathing so it can still get enough air.
Mouth breathing might seem innocuous, but when it’s driven by allergies or becomes a long-term pattern, it can have several consequences:
Breathing through the mouth dries out saliva — the mouth’s natural protective fluid. This can lead to:
Many allergy medications (especially older antihistamines) can further reduce saliva and worsen dry mouth symptoms.
Persistent mouth breathing, particularly at night, often goes hand-in-hand with poor sleep quality, snoring, or even signs of sleep-disordered breathing — leaving people feeling tired, unfocused, or irritable during the day.
In children, chronic mouth breathing can influence how the facial bones and dental arch develop. It’s associated with a longer face shape, narrow palate, misaligned teeth, and other orthodontic concerns.
The nose warms, filters, and humidifies incoming air — actions that help protect the lower airways. Mouth breathing bypasses this natural system, potentially increasing exposure to airborne particles and respiratory irritants, and may contribute to respiratory infections or make allergy symptoms feel worse.
While allergic nasal congestion is the most common allergy-related cause, other factors often tied into allergy mechanisms include:
It’s worth seeing your GP, an allergist, ENT specialist (ear, nose, and throat doctor) or other health practitioner when mouth breathing:
Professionals can assess whether allergies, structural issues or other factors are involved, and guide appropriate treatment.
Depending on the underlying causes, treatment may involve:
Allergy-Focused Approaches
Supporting Nasal Breathing
Structural or Specialist Interventions
Takeaway
Mouth breathing driven by allergies — especially allergic rhinitis — is common in Australia and can impact oral health, sleep, and overall wellbeing. Identifying allergy
triggers and managing congestion not only helps reduce the need to breathe through the mouth but can improve quality of life, especially for children as they grow.
If ongoing mouth breathing is affecting you or your child, discussing it with a healthcare provider can help pinpoint the cause and direct the right treatment.
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