Allergen Avoidance

Whatever the allergic condition it obviously makes sense for a treatment plan to start with attempts to avoid the responsible allergen(s).  If this is to be effective, then the accurate identification of allergens is important.  In the case of hay fever or rhinitis cause by a animal, this may be relatively straightforward.  pet ing rhinitis Once the offending allergen is identified, then allergen avoidance measures can be instituted.  Grass pollens can be avoided, pets removed from the home and mattresses, pillows and carpets treated to eradicate house dust mites.  If a particular food is implicated in allergic rhinitis, then that food should be excluded from the diet. Cigarette smoking should be strongly discouraged in all allergic individuals, as it will only exacerbate symptoms. Where allergen avoidance fails or is impractical, it may be necessary to commence medication to control symptoms and inflammation.

In Perennial Allergic Rhinitis, treatment should to be taken continuously, whilst in Seasonal Allergic Rhinitis treatment only need be taken for symptom control during the peak pollen season.

Antihistamines

Antihistamines are the mainstay treatment in seasonal allergic rhinitis. They control the itch, sneeze runny nose and itchy eyes. Older antihistamines such as chlorpheniramine (Piriton) control symptoms, are cheap but have significant sedating side effects. The newer non-sedating antihistamines are more expensive, cause much less psychomotor disturbance, can be taken once a day and give good symptom control. Loratidine (Clarityn), desloratidine (Neoclarityn), fexofenadine (Telfast), Mizolastine (Mizollen) and cetirizine (Zirtek), or levocetirizine (Zyzal) are recommended.

Topical antihistamines such as levocabastine (Livostin) and azelastine (Rhinolast) have been marketed and seem to be a useful adjunct when symptom control of nasal and ocular itching is intractable. They have no effect on nasal blockage and tend to have an unpleasant taste.

Nasal corticosteroids

Local administration of corticosteroids to the nasal mucosa has revolutionised the treatment of allergic rhinitis -particularly the perennial type. They control the underlying chronic inflammatory process and therefore are the treatment of choice in most patients. These preparations are safe to use for prolonged periods of time at the recommended dosages. They act on various components of the inflammatory cascade, causing vasoconstriction, reducing vascular permeability and decreasing tissue macrophage and eosinophil numbers. Nasal steroids such as Flunisolide (Syntaris), Budesonide (Rhinocort Aqua) and Beclomethasone (Beconase) are particularly useful for their prophylactic effects and newer preparations such as Fluticasone (Flixonase), Triamcinolone (Nasacort) and Mometasone (Nasonex) can be used effectively on a once daily basis

Betamethasone (Betnesol) drops may have some systemic absorption and should not be used continuously for more than 10 days. Once symptom control is achieved, the daily dosage can be slowly reduced. Intranasal steroids also control non-allergic rhinitis and reduce the size of polypoidal lesions in the nose. Occasionally they may cause local nasal irritation and nose bleeds. They do not relieve palatal and ocular itch, so antihistamines may need to be co-prescribed. If significant nasal obstruction is present at commencement of treatment, then pre-treatment with topical decongestants will be necessary.

Decongestants

Decongestants may be used topically or orally for relief of nasal blockage and congestion. Topical decongestants relieve nasal congestion very rapidly but over-use of Ephedrine is associated with rebound nasal congestion and so-called "rhinitis medicamentosa". The safest preparations are Oxymetazoline (Dristan) and Xylometazoline (Otrivine) but continuous use should be restricted to 7 - 10 days at a time.

Oral decongestants such as pseudoephedrine (Sudafed and Galpseud) also combat nasal blockage by constricting blood vessels in the nasal mucosa and throughout the body to some degree. They therefore may exacerbate hypertension, dry mucus membranes, cause bladder neck obstruction and glaucoma. Some people are also sensitive to them and experience insomnia, restlessness, headache and palpitations.

The decongestant often compensates for the sedative effect of the anti-histamine although this may result in the side effect of jitteriness and insomnia

Cromolyn

Cromolyn in the form of sodium chromoglycate (Rynacrom) has anti-inflammatory activity and relieves nasal itch, sneezing, hypersecretion and congestion particularly in seasonal allergic rhinitis. It is a particularly safe product but must be applied 4 times a day, and is also very effective in the eyes for treating allergic conjunctivitis. Cromolyns are a useful option for patients who are resistant to or prefer not to use topical steroids on an ongoing basis.

Ipratropium bromide

Ipratropium bromide (Atrovent and Rinatec) is an anticholinergic agent derived from atropine. It provides good relief from profuse watery rhinorrhoea including non-allergic or vasomotor rhinitis, a particular problem in older males with the so-called "old man’s drip". Ipratropium is very safe to use, with rapid onset of action and minimal side effects. It has no effect on nasal blockage, itch or sneezing.

Systemic steroids

A systemic steroid such as prednisilone is particularly useful in controlling nasal symptoms in allergic rhinitis and gives rapid relief especially when blockage is severe and intractable. They have significant systemic side effects and should therefore only be used in severe disease for short periods of 5 to 14 days. Use of injectable depot steroid (Depot Medrol) should be discouraged as they can lead to osteoporosis, hypertension, diabetes mellitus, glaucoma, cataracts, gastric ulceration and chronic infections.

Immunotherapy

Injection Desensitisation Immunotherapy is an effective option in severe grass pollen and Birch allergic rhinitis, which are not controlled by medication. It should be restricted to those patients who are mono-sensitised to Grass and Birch pollen or house dust mite. Potential systemic reactions such as urticaria and anaphylaxis during treatment, restrict its use to specialist units with readily available resuscitation equipment. The course of injections should be commenced before the tree or grass pollen season and usually take 3 years to complete. For many years, ALK have marketed the highly standardised Alutard SQ range of desensitising products.  At present only Grass Pollen desensitisation is undertaken in the UK.  Sublingual Immunotherapy (SLIT) given as oral drops is currently undergoing evaluation and results so far are very promising.

Other measures

Nasal douching

Normal saline douching with a touch of bicarbonate of soda added is a useful non-drug treatment for clearing the nasal passages in allergic rhinitis. It is important to use "physiological" saline for if the solution is hyper- or hypotonic, nasal mucosal damage may occur. The solution is sniffed up using a tea saucer and then expelled from the nose. Menthol nasal preparations also give some symptom relief while steam inhalations using Eucalyptus extract will help decongest the nasal passages.  Application of a small amount of Petroleum Jelly (Vaseline) to the nasal membranes with a cotton bud also helps to relieve symptoms

Complementary medicine

There is a growing demand by the general public for alternative therapies to conventional medication. These treatments are much less effective than conventional medication, but certain compounds may have some beneficial effects in allergic rhinitis. More recently the herb Butterbur was shown to have some beneficial effects. It must be stressed that these preparations give minimal therapeutic benefit and should only be offered as second line treatment to conventional rhinitis medication.

Antioxidants are particularly popular in the lay press and are aggressively marketed by manufacturers as "cure all’s". Vitamin C, Vitamin E, Beta-Carotene, Selenium and Zinc are included in this category. There is no good evidence that these products have any beneficial effect in treating allergic rhinitis. N-acetyl cysteine (Solmucol) also a mucolytic with respiratory antioxidant activity may be of some limited benefit when used in combination with conventional treatment. Other mucolytic medication such as carbocisteine, which is used in Cystic Fibrosis, is often co-prescribed in allergic rhinitis, where it has little or no therapeutic value.

New medication

The leukotriene antagonists Zafirlukast (Accolate) and Montelukast (Singulair) seem to be useful additions in treating allergic rhinitis, especially in aspirin-sensitive people. These products also seem to have beneficial effects in treating patients with asthma and co-existent allergic rhinitis as they also block the inflammatory action of Leukotrienes in the nasal mucosa.

Role of dietary restriction

Some people will benefit from empirical dietary exclusion of common food allergens such as cow’s milk, hen’s egg, citrus, alcohol and wheat in their diet. This is often tried in patients who have intractable symptoms and don’t respond to other measures. The offending food should be excluded for a 4-week period to adequately evaluate any beneficial response. The advice of a qualified dietician should be sought if a prolonged exclusion diet is instituted.

Treatment "failure"

Probably the greatest hurdle facing those entrusted with treating perennial allergic rhinitis, is that of non-compliance. Unfortunately most people will automatically stop treatment as soon as they experience some relief, only for the symptoms to return. It is particularly difficult to persuade patients to continue to take medication as a preventative measure in controlling Hayfever and allergic rhinitis.

A wide range of treatments is now available including antihistamines, decongestants and corticosteroids. Some products, such as nasal sprays and eye drops are useful if a person has localised symptoms but antihistamines are the most common form of treatment for multiple symptoms.   There are both: 

Long-acting Types:

CETIRIZINE (ZIRTEK), DESLORATODINE (NEOCLARITYN), FEXOFENADINE (TELFAST), LEVOCETIRIZINE (ZYZAL), LORATADINE (CLARITYN), MIZOLASTINE (MIZOLLEN)

These are taken regularly just once a day, but are less helpful for 'as needed' dosing

Short-acting Types:

OLD GENERATION SUCH AS CHLORPHENIRAMINE (PIRITON) AND NEW GENERATION SUCH AS ACRIVASTINE (BENADRYL)

These are quicker acting when needed, but may need to be taken several times a day for persistent benefit. 

Ask your pharmacist about these antihistamines.  Some, but not all, are available over the counter.

• Nasal sprays

There are several kinds; 

Anti-inflammatory:

Antihistamine:

Low-dose Steroids:  
These are particularly good to counteract nasal blockage and are best started a week or so before the pollen season begins. This may prevent the immune system  from becoming re-primed to react strongly, and stop the condition getting out of control as the season progresses.  They work best as a prevention (used daily) as they take a day or two to reach maximum effect if symptoms are allowed to get out of control.

•  If symptoms get badly out of control

There may be pressing reasons for getting rapid symptom relief (for example examinations), in which case a doctor can prescribe a short course of oral steroid tablet treatment (e.g. prednisolone tablets).  This is preferable to the now out-dated steroid depot injections (e.g. Kenalog) which could give troublesome side-effects.

• Desensitisation

Allergen desensitisation aims to induce the immune system to produce selective inhibition of allergic reactions by vaccinating the individual with the allergens responsible.

A variation of the original form of allergen immunotherapy (first described in 1911) is still in use.  It is used mainly to desensitise for serious allergies such as bee or wasp although great care has to be taken when using this treatment not to induce anaphylaxis (life-threatening allergy).  Some specialist units still use this treatment for severe hay fever.  Newer and safer forms of this treatment are being developed.  However, there is at present no plan to make one course of  treatment cover more than a single allergen.

A less well-known form of immunotherapy treatment is becoming popular again following the recent publication of a number of successful clinical trials.  It is called Enzyme Potentiated Desensitisation and mixtures of common allergens are used rather than single allergens.  The treatment appears to be very safe as such tiny doses of the responsible pollens are used (no more than those delivered by the skin prick test). Somewhere around a third of a million doses have been given so far without incident.  If further clinical trials confirm that it is as effective as is claimed, the treatment also has the potential to of benefit in more complex allergy problems when a number of different allergens are involved.

Another form of desensitisation, popular amongst ear nose and throat specialists in the USA, is known as Neutralisation.  In this treatment, skin testing establishes for each responsible allergen the dilution that just fails to produce a skin test response.  A vaccine containing these doses is then prepared, and the patient self-injects a minute quantity of the vaccine twice weekly.  The method is extremely safe as the testing ensures that the allergen doses are less than those used in skin prick testing, itself a very safe procedure.  As with the EPD method, further trials are needed to verify the claims of the small-scale clinical trials so far published.