Common complaints: Catarrh

CATARRH is one of those curious medical words and phrases in common use by everyone but doctors (nervous breakdown is another). Catarrh will not, then, appear on a medical certificate, but people know what it means: a persistently blocked and usually runny nose.

In children, the most common cause of catarrh is swelling of the adenoids, glands at the back of the nose which are part of the lymphatic defence system. Children suffer repeated nose and throat infections before they become immune to the common viruses, and their tonsils and adenoids become swollen as a result. Really large adenoids block the nose so completely that the child breathes through the mouth. Surgical removal is a simple and effective cure.

Adults rarely have swollen adenoids, since these glands and the tonsils tend to shrink towards the end of childhood. An adult with a persistently blocked nose is likely to have rhinitis, which is swelling of the mucous membrane of the nasal lining. Rhinitis is usually allergenic, and the best- known cause is pollen. The popular name for allergic rhinitis coming on in midsummer is hay fever, though grass pollen is only one of the many pollens that may be responsible and there is no fever. Oddly, the disorder seems to be getting more common, though pollen counts have fallen in the past 20 years.

Rhinitis that persists throughout the year is called perennial and may not be recognised as allergenic even when that is the cause. Among the triggers for perennial rhinitis are the tiny mites that live in house dust and the fur of pet animals, such as cats. Other factors that may contribute are air pollution (including the internal pollution that may occur in air-conditioned buildings) and tobacco smoke. Once allergic rhinitis is suspected, skin tests for allergy can be used to identify the triggers responsible. The best line of treatment may be reduction of exposure to the allergic trigger; for example, the density of dust mites in the home may be substantially reduced by non-fabric floor coverings and by vigorous frequent cleaning.

Decongestant sprays and inhalers may be helpful for someone who has occasional, brief attacks of hay fever, but if used every day for more than a few days the effect wears off, and there may be a rebound swelling of the nasal lining. A steroid nasal spray is likely to be more effective and will not cause rebound congestion, nor unpleasant steroid side-effects. The most effective drugs taken by mouth are the antihistamines, and those developed recently have little, if any, tendency to cause sleepiness.

Another possible cause of catarrh is chronic inflammation of the sinuses, the air- filled cavities in the cheekbones and the forehead that have ventilation channels leading into the nose. The main symptom of sinusitis, however, is likely to be headache rather than a blocked nose. Someone whose nose is painlessly but persistently or repeatedly blocked on only one side is unlikely to have allergic rhinitis. The two main possibilities are a nasal polyp - a sort of grape-like swelling high inside the nose - or distortion of the nasal septum, so that one side of the nose has a much narrower passageway than the other. Both conditions need surgery to correct them.