Allergic Rhinitis

Allergic rhinitis is an important condition because:

• It affects work and school attendance¹
• Has significant NHS costs²
• It is a risk factor for the development of asthma³

It can also be the presenting symptom of a severe systemic illness e.g. sarcoidosis or Wegener's granulomatosis.

Allergic rhinitis is a common condition characterised by an IgE-mediated inflammation of the nasal mucosa following exposure to allergens.⁴
This gives rise to a release of preformed mediators (of which histamine appears to be the most important) and chemotactic factors from the mast cells in the nasal mucosa. There is a subsequent increase in epithelial permeability and this prompts migration of inflammatory cells to the area:

• Acute phase response (minutes):
  • Sneezing occurs within minutes of exposure due to stimulation of afferent nerve endings
  • Increase in nasal secretion follows shortly afterwards, to peak 15-20 minutes after contact with the allergen
• Late-phase response (6-12 hours):
  • Characterised by nasal obstruction (although some of the acute symptoms may persist)

Classification revolves around the time-course of the symptoms as well as their severity:⁵

• Intermittent (= seasonal allergic rhinitis / hayfever):
  • 4 days or less per week OR for less than 4 weeks
  • Allergens commonly include tree pollen (spring time), grass / weed pollens (summer) and occasionally, mould spores (late summer / autumn)
• Persistent:
  • More than 4 days per week AND for more than 4 weeks
  • Allergens commonly include house dust mites and domestic pets

Severity is measured by assessing effect of symptoms on sleep and normal daily activities (including school, work, sport and leisure). If one or more is affected, the condition is deemed to be moderate or severe.

• Allergic rhinitis is a common problem, affecting over 20% of the UK population.⁶
• Onset under the age of 30 with a peak incidence in childhood and adolescence.⁷
• School-aged children and adolescents are more likely to suffer from seasonal allergic rhinitis whereas adults tend to suffer from persistent allergic rhinitis.⁴
• True prevalence unknown on account of high number of unreported, self-medicating patients but known to be high in the UK, which had the second highest rate (estimated between 10 and 20%) in Europe of symptoms reported among young teenagers interviewed in an international study.⁸
• Prevalence appears to be on the increase but interestingly, it is thought that the allergens are not becoming much more prevalent but rather our sensitivity to them is increasing, possibly as a result of dietary changes or increases in the level of air pollutants.⁹

There appear to be both genetic and environmental factors contributing to the development of allergic rhinitis. The most common allergen is the house dust mite, followed by cats and dogs.¹⁰There may be associations with other conditions:

• Conjunctivitis - more common in intermittent disease
• Atopy (including eczematous dermatitis and asthma) - more common in persistent disease
• Sinusitis and nasal polyps - more common in persistent disease⁷

Those most at risk are:¹¹

• Patients with a history of atopy
• Patients with a family history of rhinitis
• First born children
• Immigrants

Symptoms

Listen to patient's account of symptoms:

• What is the main symptom?
• How long has the condition been present?
• How frequent and severe is it?
• Is it seasonal or perennial?
• Are there trigger factors; allergic or non-allergic?
• Exposure to allergens through occupation or hobbies?
• Does patient have history of asthma, eczema, rhinitis?
• Is it drug or food induced? Remember that topical sympathomimetics, some anti-hypertensives, aspirin and non-steroidal anti-inflammatories may cause rhinitis symptoms (see below).
• Holiday time remission suggests environmental cause.

Typical symptoms may include:

• Sneezing
• Rhinorrhoea and nasal congestion:
  • This may be either anterior or posterior, leading to post-nasal drip
  • Clear – infection unlikely
  • Unilateral – is uncommon - cerebrospinal fluid (CSF) leak should be excluded
  • Yellow coloured implies allergy or infection
  • Green coloured usually associated with infection
  • Blood tinged unilateral - tumour, foreign body or nose picking
  • Blood tinged bilateral - bleeding points, nose picking or granulomatous disorder
• Itchy nose and/or palate
• Symptoms tend to be bilateral, worse on waking

Examination

• Ear, nose, and throat surgeons examine the nose with a head mirror or headlight and a nasal speculum, supplemented by rigid or flexible nasendoscopy.
• In general practice, the nose can be examined with an auriscope fitted with the largest speculum.
• A large, swollen, oedematous inferior or middle turbinate can easily be confused with a polyp; polyps, however, unlike turbinates, are usually pale grey, translucent and mobile and lack any sensation on gentle probing.¹⁰
• Look for signs suggestive of chronic nasal congestion - mouth breathing, cough, halitosis.
• Examine eyes for signs of conjunctivitis.
• Rule out other associated conditions.

• Nasal causes of rhinitis:
  • Vasomotor rhinitis
  • Infectious rhinitis
  • Gustatory rhinitis (as a result of eating spicy foods)^4,7
• Non-nasal causes of rhinitis:
  • Alcohol or cocaine abuse
  • Hypothyroidism
  • Hormonal changes of puberty and pregnancy
• Rhinitis medicamentosa:
  • Aspirin and NSAIDs
  • Clonidine, guanethidine, hydralazine
  • Some β -blockers, methyldopa
  • Some alpha-adrenergic antagonists
  • Oral contraceptives and terazosin
• Conditions mimicking rhinitis:
  • Eosinophilia syndrome
  • Nasal polyps
    • In adults a strong association exists between nasal polyps, asthma and sensitivity to aspirin - Samter's triad¹⁰
  • Adenoidal hypertrophy
  • Cystic fibrosis
  • Kartagener's syndrome
  • Systemic lupus erythematosus and granulomatous conditions e.g. Wegener's granulomatosis and sarcoidosis
  • Consider foreign bodies in the young child
• Chronic rhinosinusitis:
  • This is secondary to obstruction of the ostiomeatal complex, whether structural or secondary to an inflammatory condition. This is the area lying between the middle and inferior turbinates and the natural ostium of the maxillary sinus where the maxillary, anterior ethmoidal, and frontal sinuses drain.
  • Structural abnormalities of the nose include deviation of the nose or septum, enlarged middle and inferior turbinates, adenoidal hypertrophy (particularly in children; rare in adults) and choanal atresia.
• Leaking of cerebrospinal fluid will present with watery rhinorrhoea, often unilateral:
  • It is usually associated with trauma (including surgical trauma) or neoplasia, but spontaneous leaking may occur.
  • Nasal neoplasms are rare; the diagnosis should be considered in patients with unilateral symptoms of nasal obstruction, pain or bleeding.

History and examination should be sufficient to make the diagnosis, but additional allergy testing may be helpful when the causative allergen is not clear.

Skin prick test

Evidence from controlled trials shows the high sensitivity and specificity of skin tests.¹²

• They are important if avoidance measures are to be considered.
• When skin prick tests are not available or the patient is taking antihistamines or has dermatographism, total and allergen specific IgE concentrations in the blood may be determined (radio-allergosorbent test—RAST—or enzyme linked immunosorbent assay—ELISA).¹⁰

If this is inconclusive, the list of differentials should be considered.

Objective measures of nasal airway

These are not made in routine clinical practice but can be useful when allergen or aspirin challenges are undertaken and may be helpful when septal
surgery or turbinate reduction are being contemplated. They include peak nasal inspiratory flow, acoustic rhinometry and rhinomanometry.

Computed tomography scan

This is indicated when medical treatment has failed, the diagnosis of chronic rhinosinusitis is suspected and could not be confirmed on history and examination or neoplasia is suspected.

A stepwise approach according to the severity of symptoms, based on the available randomised trials, has been adopted by ARIA (Allergic rhinitis and its impact on asthma).¹³
Main lines of treatment are education, allergy avoidance, antihistamines and topical steroids.

General principles

Treatment strategy is guided by degree of disruption caused by symptoms; the basic principle is to avoid the causative allergen:

• Perennial allergic rhinitis is most commonly associated with allergy to house dust mite. A Cochrane systematic review examined whether effective reduction of mite levels was achieved with avoidance measures.¹⁴ These included:
  • Allergen proof bed sheets, duvets and pillow cases.
  • Sheets, blankets and duvets should be washed at least once a week.
  • Furry toys or cushions should not be kept on beds; favourite toys should be washed regularly at temperatures of at least 60°C.
  • Surfaces should be wiped with a clean, damp cloth.
  • If possible, wooden or other hard vinyl floorings should be chosen instead of carpets and roller blinds that can be wiped clean should be fitted rather than curtains.
  • Woollen blankets or feather bedding should not be used in the home; synthetic pillows and acrylic duvets can be tried instead.
  However, whether effective reduction of mite levels was achieved in many studies was not clear.
• Patients who are found to be allergic to furred animals should reduce their exposure as much as possible and be discouraged from having pets in the home.
• When going outdoors, avoid fields, newly mown grass and picking flowers or fruit.
• Choose car with air conditioning (some have pollen filters)
• Follow pollen count reports

It was found that the benefit of using a single measure to improve symptoms of perennial rhinitis was questionable. Efforts to obtain maximal mite elimination may lead to clinical benefits in selected highly motivated patients and clinical benefits are most likely with multiple interventions.¹⁵

Medical treatment

• Topical nasal antihistamines:
  • They have superior effects to oral antihistamines for rhinitis symptoms, but do not reduce symptoms at other sites e.g. eyes.¹⁶
  • They are fast acting (less than 15 minutes) so are a useful 'rescue'.
• Oral antihistamines:
  • Regular therapy is more effective than 'as required'.
  • A recent review of randomised controlled trials confirmed the efficacy of oral antihistamines in persistent allergic rhinitis.¹⁷
  • Their effect is predominantly on neurally mediated symptoms of itch, sneeze and rhinorrhoea.
• Topical intranasal steroids:
  Most patients will attain good control on intranasal steroids and a large body of data shows that they are effective for all symptoms of allergic perennial rhinitis, including nasal obstruction, itching, sneezing and watery rhinorrhoea.¹⁸
  • Modern intranasal steroids are safe for long term use in adults when used within the recommended dosage.
  • In children, they should be used at the lowest dose that controls symptoms, particularly when used concurrently with other inhaled or intranasal steroids.¹⁹ Beclometasone has a worse safety profile than mometasone, budesonide or fluticasone.⁶
  • Occasionally, intranasal steroids may be associated with dryness, crusting or slight bleeding, which if recurrent may necessitate withdrawal of treatment.
• Others:
  • Sodium cromoglycate is less effective than antihistamines and corticosteroids and needs frequent use (up to five times daily), which may compromise compliance.
  • The anticholinergic intranasal agent ipratropium bromide is effective in controlling watery rhinorrhoea, particularly if this is the dominant symptom. The dose may need to be titrated against symptoms.
  • Oral antileukotrienes have been shown to be effective in allergic rhinitis in randomised controlled trials.¹⁸ They may be beneficial in patients with aspirin sensitivity.

Other treatments such as nasal decongestants and oral steroids should be used only in certain situations:

• Topical nasal decongestants may be useful at the start of treatment to "open up" the nose and should be used for less than two weeks to avoid the risk of developing "rhinitis medicamentosa".
• Oral steroids should be used only as a last resort when other treatments have failed.

Surgical treatment

When drugs fail and a structural abnormality exists, surgery may be indicated:

• Surgical reduction of the inferior turbinates or correction of a deviated nasal septum or nose may be needed to improve the airway or at least to improve access for topical medical treatment.
• Surgery has a role in the management of nasal polyps and sinusitis when these conditions fail to respond to medical treatment,²⁰ particularly with the advent of minimally invasive endoscopic sinus surgery.

Immunotherapy

This is administered by the subcutaneous or sublingual route (SLIT) and has been shown to be effective in both seasonal and perennial allergic rhinitis in patients with proven IgE mediated disease and a limited spectrum of allergies.²¹

Its use is confined to those patients in whom a perennial allergen is the dominant cause and in whom avoidance measures and medical treatment are either not effective or not tolerated owing to side effects.

NB: The presence of chronic bronchial asthma is a contraindication to immunotherapy in the United Kingdom.

• Sinusitis
• Nasal polyps
• Chronic otitis media

This condition often improves over the years - particularly seasonal allergic rhinitis, which may spontaneously resolve in up to 20% of patients.⁴