Update on the treatment of allergic rhinitis

Allergic rhinitis is a common IgE-mediated disease and is associated with both nasal and ocular symptoms. Common presenting nasal symptoms include congestion, itching, rhinorrhoea and sneezing. Nasal symptoms are frequently accompanied by ocular ones, such as itchy eyes, watery eyes and redness. 

Most patients who see their doctor have moderate to severe disease, meaning that one or more of the following applies: sleep disturbance; impairment of daily activities, leisure and/or sport; impairment of school and or work; troublesome symptoms. These patients experience a negative impact on their quality of life, on their work and on their productivity.

Burden of allergic rhinitis

The plight of individuals who suffer from a reduced quality of life and productivity due to allergic rhinitis has been  highlighted by the European Academy of Allergy and Clinical Immunology (www.eaaci.org) and at EU parliament level. Unfortunately, it has been shown that most patients are dissatisfied with their current control of allergic rhinitis and many patients find themselves on multiple medications to control the disease process. The most common medications used are a combination of antihistamines and intranasal corticosteroids, often with less than adequate control.

Current guidelines for the treatment of allergic rhinitis based on ARIA (Allergic Rhinitis and its Impact on Asthma, see www.whiar.org) place intranasal corticosteroids as first-line treatment. Second generation antihistamines may be required, as may ocular mast-cell stabilisers (cromogylates, etc). New combination intranasal antihistamine/corticosteroid sprays have proven effective in moderate to severe allergic rhinitis and several studies have found this an effective treatment. 

Diagnosis of allergy

The definitive evidence of allergy, after appropriate history and examination, should be ascertained by either specific IgE measurements or by skin-prick testing. There is little value of total IgE measurements and no role for non-medical tests such as kinesiology, VEGA testing or food intolerance testing for rhinitis.

Medical care

The management of allergic rhinitis consists of four major categories of treatment:

• Environmental control measures and allergen avoidance 

• Pharmacological management

• Immunotherapy

• Surgery.

Environmental control measures and allergen avoidance involve both the avoidance of known allergens (substances to which the patient has IgE-mediated hypersensitivity) and avoidance of non-specific or irritant triggers. Consider environmental control measures, when practical, in all cases of allergic rhinitis. This reinforces the need for proper and accurate allergy testing.

Pollens and outdoor moulds

Reduction of outdoor exposure during the season in which a particular type of pollen is present can be helpful. However, it is not ideal to restrict the movement of patients when the weather becomes better, nor is it possible in most cases. In general, tree pollens are present in the spring, grass pollens from the late spring through summer and weed pollens from late summer through autumn, but exceptions to these seasonal patterns exist. 

Area-specific pollens such as ragweed and rapeseed may also be of importance in certain parts of Ireland. Certain pollen counts tend to be higher on dry, sunny, windy days. Outdoor exposure can be limited during this time, but this may not be reliable because pollen counts can also be influenced by a number of other factors. 

Keeping the windows and doors of the house and car closed as much as possible during the pollen season (with air conditioning, if necessary, on recirculating mode) can be helpful. Taking a shower after outdoor exposure can be helpful by removing pollen that is stuck to the hair and skin.

Despite all of these measures, patients who are allergic to pollens usually continue to be symptomatic during the pollen season and usually require some other form of management. As with pollens, avoidance of outdoor/seasonal moulds may be difficult. Symptomatic therapy with newer generation antihistamines, nasal corticosteroids and ideally immunotherapy for more severe cases may be necessary. 

Indoor allergens

Depending on the allergen, environmental control measures for indoor allergens can be quite helpful. House dust mites are the most common cause of rhinitis throughout the world and this is also the case in Ireland, where there are perennial allergens. They tend to peak during the cooler months when the windows are closed and the central heating is on. This also coincides with a spike in rhinitis and asthma during the cooler months.

Impermeable mattress covers are useful to reduce exposure to dust mites, as is hot washing linen every two weeks. Remove carpets if possible or use a HEPA-based vacuum cleaner. Indoor environmental control measures for mould allergy focus on reduction of excessive humidity. The environmental control measures for dust mites can also help reduce mould spores.

For animal allergy, depending on the strength of the allergy, complete avoidance is the best option. For patients who cannot or do not wish to avoid the pet, confinement of the animal in a non-carpeted room may be beneficial, with the exception of large animals, where pre-dosing with antihistamines may be required for occasional contact. In all cases, immunotherapy is also available in respect of occupational allergy to animals.

Non-specific triggers

Exposure to smoke, strong perfumes and scents, fumes, rapid changes in temperature (vasomotor rhinitis) and outdoor pollution can be non-specific triggers in patients with allergic rhinitis. Consider avoidance of these situations or triggers if they seem to aggravate symptoms.

Immunotherapy (desensitisation)

Injectable

A considerable body of clinical research has established the effectiveness of high-dose allergy subcutaneous injections in reducing symptoms and medication requirements. Success rates have been demonstrated to be as high as 80-90% for certain allergens. It is a long-term process; noticeable improvement is often not observed for six to 12 months, and, if helpful, therapy should be continued for three years. 

Injectable immunotherapy is not without risk because severe systemic allergic reactions can sometimes occur. The risks/benefits should be weighed against other management options.

Immunotherapy may be considered more strongly with severe disease, poor response to other management options and the presence of comorbid conditions or complications. Immunotherapy is often combined with pharmacotherapy and environmental control.

Administer immunotherapy with allergens to which the patient is known to be sensitive and that are present in the patient’s environment (and cannot be easily avoided). The value of immunotherapy for pollens, dust mites, and cats is well established. The value of immunotherapy for dogs and mould is less well established.

There are contraindications and immunotherapy should only be performed by individuals who have been appropriately trained, who institute appropriate precautions and who are equipped for potential adverse events. This route is still used extensively in the US and in other parts of Europe.

Sublingual

Sublingual immunotherapy is increasing in use, particularly in Europe, because of its safety and efficacy and the fact that it is licensed and reimbursable for some patients.

Ireland has had two sublingual immunotherapy treatments for grass pollen registered and available (by GMS and on the Drugs Payment Scheme) since 2008. Oralair (five-grass pollen extract) and Grazax (Timothy grass extract) has been used for patients with severe grass pollen allergy where standard antihistamine and other medicines fail to provide relief. This is effective in dampening hay fever for at least five years after completion of treatment.

Sublingual immunotherapy for house dust mite allergy has been used on a ‘named patient basis’ in liquid form as sublingual drops with efficacy and safety. The tablet form of this treatment is now on the horizon with approvals in some European countries. 

Surgery

For some patients with recurrent sinusitis, nasal polyposis, septal deviation or refractory allergic rhinitis, nasal surgery will be necessary.