Rhinitis and sinusitis
	Allergic rhinitis
	Non-allergic rhinitis
	Frequent colds: viruses or allergy?
	Sinusitis
	Nasal polyps

Rhinitis is the name given to a group of conditions that are caused by inflammation of the lining of the nose.  There are a variety of types and not all are caused by allergy.  All of these conditions cause a constant set of symptoms, whatever the cause.  These include nasal discharge, nasal obstruction, nasal itching, sneezing and post-nasal drip or phlegm.  The type that occurs during only the spring or summer, is called seasonal allergic rhinitis, the medical term for hay fever, and this is discussed separately.  When rhinitis is present all year round it is called perennial (= persistent) rhinitis and in such cases skin tests for allergy may be positive or negative.  

Perennial rhinitis is common, and skin prick testing will show if obvious allergy is the cause.  Cases with skin tests positive are similar to hay fever, and the results of such tests may show allergy to a number of common items such as house dust mite, cats dogs and other pets, and fungal spores. 

The symptoms of chronic rhinitis will often come and go, whether or not allergy is the cause, and frequent attacks of sinusitis are common.  For this reason many sufferers do not realise that this is their problem, preferring to blame colds, a condition that is more correctly called a viral rhinitis.  This distinction is often difficult, even for a doctor, as a cold is simply a short episode of rhinitis that is caused by a virus.  Skin prick testing may be useful to show if allergic rhinitis may be the cause.  Cases of chronic rhinitis with skin tests negative and which are not caused by viruses are very common.  Such cases are difficult to define, and finding a cause can be difficult. 

Frequent colds; viruses or allergy?

The common cold and hay fever are both types of the very common condition caused rhinitis. Viral rhinitis is one form of rhinitis that everyone has experienced, it is another name for the common cold.  However, patients suffering from allergic rhinitis, perhaps caused by grass or tree pollens (hay fever), dust mites, pets, feathers or fungal spores often claim that they are suffering from frequent colds, because they have never realised that an allergy might be at the heart of the problem.  The chart below shows the typical features for both the viral and the allergic form of the condition, and from this it can be seen that the two can easily be confused.  Even doctors can find this distinction difficult to make without referring the patient for allergy tests.

Whilst the above may help the patient decide whether colds or allergy are the problems, allergy skin tests are the best way to be sure.

Other investigations
Nitric oxide (NO) levels in exhaled air from the nasal passages tends to be raised when allergic inflammation is present.  Nitric oxide testing can be quickly and easily performed in the clinic and it gives a useful measure of the degree of allergic inflammation present.  The same equipment can measure nitric oxide levels in the air expired from the lungs, and this assesses if the type of inflammation that causes asthma is also present.  The test can also be used to assess the response to treatment.

Ear nose and throat specialists may use nasal endoscopes to inspect the turbinates (the fleshy folds in the nose), the nasal septum and the osteo-meatal complex; the area that links the nose with the nasal sinuses.  X-Ray techniques (conventional X-Rays and CT scans) do not assist with the diagnosis of allergic rhinitis, but can be useful to identify complications of rhinitis such as sinusitis, infections and nasal polyps.

Allergic rhinitis

In order to find out which patients with rhinitis are suffering from allergy a good clinical history needs to be combined with skin prick testing for the common inhalant allergens. 

These help to confirm the causative allergen and the results are immediately available.  Showing the patient the "weal and flare" reaction is a useful way of demonstrating to the patient the inflammatory nature of allergic rhinitis.

Hay fever is a type of rhinitis that is caused by a particular kind of allergy.  The commonest cause in the UK is grass pollen, although tree, weed, garden flower and shrub pollens may all be involved.  The condition is discussed separately.

As well as allergy to pollens, skin tests may also pick up allergy to other seasonal allergens such as outdoor fungal spores.   When skin tests pick up allergy to items that are present all the year round, then persistent or intermittent all-year-round (perennial) symptoms will more usually occur.  Sufferers of this perennial form of allergic rhinitis will often be found to be positive to house dust mite, and often also to cat, dog, other animals and feathers.  Many patients test positive to both seasonal and perennial allergens, and when the perennial symptoms are particularly troublesome, they may not be able to distinguish which of their symptoms are caused by seasonal rhinitis or hay fever.

Non-allergic rhinitis

Some patients have all the symptoms of nasal allergy, but the standard allergy tests prove negative.  In the past it was convenient to refer to this condition as non-allergic rhinitis although in view of recent developments suggesting that many of these cases may turn out to be due to a type of allergy after all the alternative name idiopathic rhinitis is probably better.  Idiopathic simply means that the causes are at present unknown. 

Food intolerance
So if skin tests are negative in many cases of rhinitis, how will we suspect if an allergy might be the cause?  Often there may be clues from the history.  Some patients may have heard that avoiding milk sometimes helps chronic rhinitis.  Some will have tried it and are convinced that this is so.  However, allergy skin prick tests may fail to confirm this allergy.  When this happens, it can be tempting for doctors to suggest that such a relationship is all in the mind.  However, many studies have now been undertaken that have used elimination diets and blinded challenge tests to confirm that such reactions are genuine.  When food elimination clears symptoms and food challenge tests are positive in the presence of negative allergy skin or blood tests, the condition is known as food intolerance.

Unfortunately elimination diets are tedious, and they require a co-operative and able patient and the support of an experienced doctor or dietitian.  However, in spite of this they can sometimes be extremely helpful in establishing the cause of chronic ear, nose and throat symptoms.  Although milk is a common culprit, many other foods can also be involved.

Food additive intolerance
Although there is little work published concerning this possibility, a recent study from Verona in Italy suggests that the possibility that some subjects with chronic rhinitis might be sensitive to certain food additives should at least be considered.

Two hundred and twenty-six consecutive patients (76 males and 150 females) aged 12-60 years spent 1 month following an additive-free diet regimen, and a food additive-rich diet was followed for a further 2 weeks.  After this period, blinded challenges were undertaken with a range of food colours and preservative. 

Twenty subjects (8.8%) reported either became symptoms-free or reported an improvement.  20 challenges with sodium benzoate induced both objective (i.e. sneezing and watering) and subjective symptoms (nasal blockage and nasal itching) of rhinitis with an increase in measured nasal blockage.  45 challenges induced subjective symptoms of rhinitis (i.e. nasal blockage and nasal itching), two with tartrazine, seven with erythrosine, 19 with sodium benzoate, three with p-hydroxybenzoate, six with sodium metabisulphite, and eight with monosodium glutamate, respectively.

Mould spore sensitivity
The suspicion that mould spore sensitivity may be important in a particular case might be strong, even though skin prick tests are negative.  

The patient may notice that the one time that their symptoms completely clear is when on  holiday abroad in a dry climate.  Symptoms may then recur swiftly on  returning home and subsequent observation might confirm that symptoms are worse in damp conditions, in rooms and buildings where condensation or visible mould is present, or in greenhouses and conservatories.  In such patients the first sharp frost of winter, known to be associated with a marked reduction of outdoor fungal spore counts, will often improve matters considerably for them, particularly when out-of-doors.

The possibility that exposure to fungal spores may be an important cause of rhinitis is obviously important to the patient.  Measures taken to control damp and the growth of mould in the patient's home are obviously important.  The information can also be valuable if a move of house is contemplated.  

However a fresh dimension to the possible importance of allergy to fungal spores in chronic rhinitis has arisen as a result of recent work at the Mayo Clinic in the USA.  Researchers have found that fungal spores are present in the nasal and sinus secretions of the majority (over 90%) of chronic rhinosinusitis sufferers.  When these patients were tested for allergy to those fungal spores the standard (skin prick or RAST) tests were negative.  However because of the presence eosinophil cells in the nasal and sinus secretions of these patients they have proposed that a different type of allergy may be causing the nasal and sinus symptoms in these patients.  Although antifungal drugs given by mouth do not appear to help, early studies using a dilute antifungal solution as a nasal lavage are promising. This treatment also appears to help nasal polyp sufferers.  Further studies of this kind of treatment are underway.

Rhinitis treatment

From the above it can be seen that the identification and avoidance of what is causing the rhinitis should be the primary aim.  However, identifying the cause is not always possible, and avoiding the cause once it has been identified is not always straightforward.

After avoidance, the other methods for controlling the symptoms of rhinitis can be divided into drug treatments, desensitisation and other treatments.

Sinusitis

Viral and allergic rhinitis are more often than not complicated by varying degrees of sinusitis, a condition that can itself become chronic (persistent).  Therefore, in reality, rhinitis and sinusitis very often co-exist (some experts say that you cannot have one without the other), hence the term rhinosinusitis.  Recent research has now shown us that the majority of asthmatics suffer varying degrees of rhinosinusitis, even if they are not strongly aware of the symptoms, an association that suggests that there are likely to be similar environmental causes for both conditions.  

However when you consider that the respiratory tract is made up of not only the lungs, bronchi and trachea but also the nose, sinuses and throat, then this is perhaps not surprising.  The connection is an important one, as for those asthmatics who are unaware of their chronic rhinosinusitis, an important area for treatment is ignored.  There is no doubt that the effective diagnosis and treatment of rhino-sinusitis is of enormous benefit to many asthmatics.  This important connection has now been officially recognised; and an international set of guidelines has been produced, sponsored by the World Health Organisation.  

Nasal polyps

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