Catarrh is an excessive build-up of thick phlegm or mucus in an airway or cavity of the body.

It is usually found in the sinuses (air-filled cavities in the bones of the face that drain into the nose), but it can also occur in the throat, ears or chest.

This can lead to:

• a blocked and stuffy nose
• a runny nose or mucus that runs down the back of your throat
• an irritating, persistent cough caused by excess mucus at the back of your throat
• a headache
• facial pain caused by a blocked nose and blocked sinuses
• a loss of smell and taste
• temporary, partial hearing loss and a crackling sensation in your middle ear
• tiredness

What causes catarrh?

Catarrh is caused by the immune system reacting to an infection or irritation. The immune system is the body's natural defence against infection and illness.

Your immune system sends infection-fighting white blood cells to the source of the infection or irritation. These release molecules called inflammatory mediators which cause the mucous membranes to swell and produce mucus. The swelling also narrows the cavity, resulting in further congestion.

Catarrh is not a condition itself, but a symptom of conditions such as:

• the common cold or other infections
• hay fever or other types of allergic rhinitis – nasal inflammation caused by an allergic reaction to allergens such as pollen, animals or dust mites
• non-allergic rhinitis – sensitivity to environmental triggers, such as changes in humidity  
• nasal polyps – fleshy swellings inside the nose

The links above provide more detailed information on these conditions.

Chronic catarrh

In some cases, people can experience chronic catarrh, which is not caused by an allergy or infection and lasts for a long time. The cause of chronic catarrh is unknown but it may be related to an abnormality in the lining of the throat.

Should I see my GP?

In most cases, catarrh will clear up as the underlying infection only lasts a short period of time.

However, some people may experience chronic catarrh, which can be frustrating to live with.

If your catarrh persists, speak to your GP. They may want to rule out conditions such as nasal polyps and find out if your catarrh is being caused by an allergic reaction.

Self-help techniques are often the best way of managing chronic catarrh if a cause cannot be found.

Treating catarrh

If your catarrh hasn't cleared up on its own, your treatment will depend on the underlying cause.

When no cause can be identified, self-help techniques are the best way to relieve symptoms. This may include:

• simple environmental changes – such as avoiding warm, dry atmospheres
• avoiding dehydration
• saline nasal rinses
• decongestant medicines

Read more about how catarrh is treated.