Blocked nose and mouth breathing

What are the common causes of nasal obstruction in kids?

The most common causes in kids are nasal allergies and large adenoids. Other causes are possible and are assessed as part of the ENT consultation, which may include examining the nose with a small endoscope.

What to look for?

  • Mouth breathing - often more apparent at night, may result in drooling at night.
  • Snoring or poor sleep quality.
  • Teeth grinding at night.
  • Hyponasal voice - flat, muffled sounding, often described as nasal sounding.
  • Nasal itch, runny nose - may be symptoms of allergy.
  • Problems with the teeth due to drying from mouth breathing.
  • Problems with the way the jaws and teeth are growing, often detected by a dentist or orthodontist.

Nasal allergy

Nasal allergy (called allergic rhinitis) is common and can go together with childhood asthma and eczema. Apart from a blocked nose, the child will often rub or itch their nose (and eyes) a lot and may have a runny nose which is usually clear. The allergic reaction causes swelling of the lining of the nose, particularly of structures called inferior turbinates, which then block the nose.

Allergy testing can be performed – ideally with skin prick testing through an allergist. Blood tests can also be used. However, trying to avoid nasal allergies is often not particularly effective.

Treatment is often with medications initially, and if this controls the blocked nose, immunotherapy (also known as desensitisation) may also be a good option longer term. Otherwise, surgery can be used to reduce the size of the turbinates.


The adenoid is a structure in the very back of the nose which is the same type of tissue as the tonsils (lymphoid tissue). In some kids it can be larger than usual and result in a blocked nose, or become chronically infected which can lead to a constantly snotty nose and sometimes ear infections as well. The adenoid isn’t usually visible through the mouth or from the front of the nose and, if needed, we may examine it by using a small flexible endoscope through the nose. If there is a large or infected adenoid your surgeon may recommend adenoidectomy.