The Australasian Society of Clinical Immunology and Allergy

Allergic rhinitis is a common disorder, and in recent studies has been shown to affect up to 40% of the population. Its prevalence has doubled over the past 25 years.

Final Version 25 November 2000

Clinical presentation

Allergic rhinitis can occur at any age, even under the age of two years. Most cases, however, start in the teens or early adult life and improve by middle age. Classical symptoms are sneezing, itching and copious, thin, watery discharge, but nasal obstruction is also often present, especially in perennial rhinitis. Infants with rhinitis have nasal discharge and obstruction and this may interfere with feeding and contribute to irritability.

Allergic rhinitis may masquerade as continuous or recurrent colds, frequent sore throats, mouth breathing and snoring, a feeling of pressure over the sinuses, recurrent infective sinusitis, and headaches. Allergic rhinitis should always be considered in young children with recurrent upper respiratory tract and ear infections. Children rarely suffer from nasal polyps, and when they do it is important to exclude cystic fibrosis and primary ciliary dyskinesia.

Adjacent structures such as the Eustacian tube and sinuses (which share a common lining with the nose) may be involved as well. Obstruction to sinus ostia prevents drainage, and stasis of secretions results in sinusitis and recurrent otitis media in children. (fig 1 page 3)

Seasonal Rhinitis

Seasonal allergic rhinitis or hayfever is due to pollen allergy, most commonly grass pollens in Australia. Symptoms start abruptly in Spring and continue for a variable time depending on the geographical area. Occasionally tree and weed pollens may be responsible. Symptoms are worse out of doors.

Perennial allergic rhinitis

Perennial allergic rhinitis is usually due to house dust mite allergy. Symptoms are often worse at night or in the early morning. Other indoor allergens giving rise to perennial symptoms include cat and other animal danders, cockroach and moulds.

Food allergens

Food allergens in isolation are seldom the offending agents in infancy and almost never in adults.

Quality of life.

Allergic rhinitis and sinusitis can have a significant impact on activities of daily life, giving rise to fatigue and malaise, impairment in concentration and headaches, and in children to learning and behavioural difficulties. Often the degree of disability is only truly appreciated after they have been treated successfully. These symptoms are explained partly by the discomfort of the disease itself, partly by the treatment especially if first generation antihistamines or cold remedies are used, and partly by interference with sleep caused by nasal obstruction and post-nasal drip.

Differential Diagnosis of Allergic Rhinitis (See Box 1 on page 3)

A common problem for patients is the distinction between allergic rhinitis and the common cold. Watery rhinorrhoea tends to persist in allergic rhinitis whereas in the common cold secretions thicken and become discoloured. Itching of nose, eyes, palate and ears is more prominent in allergic rhinitis.

Foreign bodies in the nose are usually found in children. They present with a unilateral offensive and often bloody purulent nasal discharge. Repeated use of topical nasal decongestants can lead to rebound swelling of nasal mucosa with the need to use ever increasing amounts of medication, a condition known as rhinitis medicamentosa. This can eventually lead to atrophic rhinitis.

Investigations

Skin prick testing or RAST should be done in all patients with persistent or recurrent rhinitis who have sufficient symptoms to warrant a visit to the doctor, in order to distinguish allergic from non-allergic rhinitis, and to confirm the identity of potential allergens. There are regional differences in allergen prevalence, and the appropriate allergens need to be selected. Total serum lgE is unhelpful to distinguish between allergic and non-allergic rhinitis.

Other procedures are usually undertaken by specialists. Plain X-rays are usually unhelpful and should not be done as a routine. CT scans of paranasal sinuses may be indicated after failure of conservative treatment. Mucosal changes in paranasal sinuses accompany allergic rhinitis in more than 50% of cases and do not of themselves imply the presence of infective sinusitis. Flexible rhinoscopy can delineate enlarged turbinates, confirm the presence of polyps and foreign bodies, and may show the presence of a tumour.

Management

By the time that patients present to the doctor, they have moderately severe disease, and have probably used over-the-counter medications for some time with only partial relief or with unwanted side-effects. Management should be designed to -

1. Identify precipitants and advise on their avoidance.
2. Antihistamines are often the first line of treatment. Having a systemic effect they are particularly useful where there is multiple organ involvement, for example allergic conjunctivitis and atopic eczema together with allergic rhinitis. They are most effective for relieving itching, sneezing and rhinorrhoea, and are less successful in managing nasal obstruction, when combination with an oral decongestant may be more helpful.
3. Topical corticosteroids are very effective in allergic rhinitis. They need to be used regularly as prophylactic agents and are not intended to relieve acute symptoms. Careful patient education is necessary to ensure correct usage of the drug. Once control of symptoms has been achieved the dosage should be reduced progressively to the minimum consistent with control of symptoms. Prolonged therapy may be required and they can be used long-term with safety.
4. Oral decongestants such as pseudoephedrine or phenylephrine on their own or in combination with an antihistamine, are useful for relieving obstruction and nasal congestion in the short-term. They should be used with caution in hypertension, angina, prostatism and thyrotoxicosis, and they are contra-indicated in patients taking monoamine oxidase inhibitor antidepressants. Side-effects include restlessness, insomnia, and tachyarrhythmias.
5. Decongestant nasal sprays or drops can be used in the short-term up to a maximum of 5 days to open the air passages to allow topical corticosteroids access to the nasal mucosa.
6. Other topical treatments include:
   • Ipratropium bromide, an atropine-like anticholinergic agent which is very effective in reducing watery rhinorrhoea.
   • Levocabastine, a topically active antihistamines, is rapid in onset, well tolerated, and effective in relieving both nasal and eye symptoms.
   • For associated conjunctivitis lodoxamide 0.1% and sodium cromoglycate are highly effective agents.
   • Saline sprays on a regular basis are helpful for relief of obstruction and thick secretions.
7. Antibiotics and analgesics may be required for acute sinusitis.
8. Systemic corticosteroids are indicated for allergic rhinitis only in exceptional circumstances where there is intense irritability of the nose or severe obstruction. There is no justification for the use of depot injections of steroids.
9. Immunotherapy (desensitisation) is an effective adjunct to drug therapy in selected patients. It should be prescribed only by allergy specialists and only after allergen avoidance and drug treatment have been instituted. There is no place for sublingual immunotherapy at this time.
10. Surgery. The usual indications for surgery are persistent nasal obstruction and chronic refractory sinusitis. Surgery gives great short-term benefit, but the condition tends to recur unless appropriate steps are undertaken to deal with any underlying allergic factors.

Differential diagnosis of allergic rhinitis

• The common cold.
• A foreign body.
• Non-allergic rhinitis.
• Adenoid hypertrophy.
• Structural abnormalities.
• Pregnancy.
• Drugs such as some antihypertensives and parasympathomimetic agents.
• Repeated use of topical nasal decongestants.
• Atrophic rhinitis, e.g. sicca syndrome, abuse of topical decongestants.
• Other diseases, e.g. Wegener's granulomatosis, tumours.

Who should be referred to an allergy specialist?

• If the diagnosis is in doubt
• If the precipitating factor is not identified
• Failure to respond to conventional therapy
• Interference with normal daily activities or sleep
• When complications of therapy occur
• If facilities are not available for performance and interpretation of skin prick tests
• If desensitisation is contemplated

Practice Points

• Make a positive diagnosis
• Identify provoking allergens
• Avoid provoking allergens where possible
• Discourage excessive topical corticosteroids
• Refer for consideration of desensitisation if conservative measures fail.

Further reading

• Walls RS. Rhinitis. In "Allergies and their Management". MacLennan and Petty, Sydney, 1997, pp 65-78.
• International Consensus Report on the Diagnosis and Management of Rhinitis. Allergy. 1994; 49:Supplement 19:5-34.