US Pharm.
2008;33(7):12-15.
Allergic rhinitis (AR) is a
common medical condition that afflicts millions of Americans. Providing
education about causes, avoidance measures, and treatment options can help
reduce the burden to patients. The pharmacist is in an ideal position to help
prevent and alleviate the suffering of those asking for assistance with AR.
Prevalence
Allergic rhinitis
is thought to affect as many as 25% to 30% of adults and 40% of children, with
an estimated prevalence of 20 to 40 million U.S. residents.1,2 AR
was once less common, but the incidence has steadily been increasing, perhaps
due to such factors as increasing pollution, more time spent indoors, and the
installation of indoor carpeting.3,4 The prevalence is now so high
that AR has been identified as the most common medical condition of childhood.5
Etiology
The common thread
in AR is inhalation of an aeroallergen, which initiates a cascade of events
involving immunoglobulin E (IgE), leading to degranulation of mast cells or
basophils and the subsequent release of preformed inflammatory mediators.2,6,7
Triggers
A host of
aeroallergens trigger AR. The causes are so diverse that clinicians classify
the condition based on the temporal nature of the attacks.8 Some
patients suffer from AR at virtually any time of the year, without respect to
any discernible time pattern. These patients are said to experience perennial
AR.9 The causes include such provoking factors as dog/cat
dander, dust mite residue, cleaning sprays, cosmetics, cigarette smoke,
cockroaches, and molds.7
Other patients have seasonal
AR, experiencing symptoms that worsen markedly at certain predictable
times of the year. These usually coincide with the presence of a specific type
of pollen, such as plant, weed, or tree.
The classification of AR cases
as seasonal or perennial is not mutually exclusive. A patient may have both.
The patient may be allergic to cat dander, but also to pollens. Thus, he or
she may experience symptoms year-round, but with an increased incidence of
episodes during the peak pollen seasons. Mold allergy can cause both types of
AR. The patient may complain of symptoms after taking a shower or when in the
bathroom due to household mold. The number of episodes may increase after
seasonal rains, when molds in the outside environment sporulate in response to
the increased moisture.
Manifestations
Patients with AR
typically experience a constellation of symptoms.5,8 The most
bothersome and prevalent involve the nose and its function. The nasal passages
become congested, impairing the ability to breathe and the sense of smell, as
well as requiring the patient to attempt to blow the nose to clear it. The
nose also produces clear, watery discharge, necessitating frequent wiping. The
nose begins to itch, especially in the posterior portion, causing the patient
to attempt to relieve it by rubbing the nose with the heel of the hand. The
patient also experiences paroxysms of sneezing, as many as 10 to 20 in a row.
While the sneezes may resemble the loud lung-clearing sneezes that
characterize the common cold, they are more commonly shallow and barely
audible.
Ophthalmic symptoms such as
conjunctivitis, pruritus, and redness can be caused by AR. It can increase the
risk of sinusitis, otitis media, and asthma, and cause sleep disturbances,
malaise, weakness, and fatigue.1,8,10 AR may also have more
far-reaching consequences, including reduced quality of life, psychological
effects, and impaired ability to process cognitive input, leading to learning
disability.11
Patients with AR have reported
the following symptoms: congestion (78%), rhinorrhea (62%), postnasal drip
(61%), ophthalmic redness and pruritus (53%), tearing (51%), sneezing episodes
(51%), headache (51%), pruritus (46%), facial pain (43%), and ear pain (30%).11
Avoidance Interventions
The obvious advice
for patients with AR is complete avoidance of the offending allergen.7
Allergen avoidance techniques include proper household cleaning to reduce dust
mites and molds, avoiding contact with pets, using hypoallergenic bedding and
air purifiers, and minimizing outdoor activities. However, avoidance is
difficult at best and may be virtually impossible.
Nonprescription Options
Due to the
impracticality of allergen avoidance, many patients require medical therapy.
The first-line agents are less-sedating second-generation antihistamines, two
of which are now available on a nonprescription basis: cetirizine (Zyrtec) and
loratadine (Claritin, Alavert).10,12,13 In addition to the standard
warnings against use if pregnant or breastfeeding, both agents are also
contraindicated in patients with liver or kidney disease, and cetirizine must
not be taken by patients with an allergy to hydroxyzine.
The patient's age must be
discovered prior to making a recommendation. Some products (e.g., Children's
Claritin Syrup, Children's Zyrtec Liquid) are FDA approved for use in patients
as young as 2 years. Furthermore, cetir izine is not considered safe for
self-use in patients aged 65 and older.
Loratadine is generally
considered nonsedating. Cetirizine is usually given this designation, but a
careful examination of its nonprescription product label reveals that the
potential for drowsiness is greater than for loratadine.14
Nonprescription cetirizine products carry specific labels to warn the patient
that drowsiness may occur. Thus, the patient with concerns about drowsiness
might benefit from a recommendation for loratadine rather than cetirizine.
First-generation
antihistamines remain available as nonprescription products, but the increased
incidence of sedation in patients has caused them to be largely eclipsed by
the safer second-generation antihistamines. First-generation antihistamines
include diphenhydramine (Benadryl), chlorphenir amine (Chlor-Trimeton), and
clemastine (Tavist). They are contraindicated in patients with difficulty in
urination due to enlargement of the prostate, glaucoma, or breathing problems
such as emphysema or chronic bronchitis.15
The age of the patient must
also be noted carefully before the pharmacist makes a recommendation for a
first-generation antihistamine. None are FDA approved for use in patients
under the age of 6 years. Oral decongestants may be necessary to relieve nasal
congestion that is not treated by antihistamines.7
The pharmacist can also
suggest a trial of intranasal cromolyn sodium (Nasalcrom) for patients aged 6
years and older.7,15 Used as directed one week before exposure to a
known or suspected allergen, it can prevent symptoms from developing. It can
also be used each day that the patient is in contact with the provoking agent.
It should not be recommended for patients with fever, discolored nasal
discharge, sinus pain or infection, wheezing, asthma, or cold symptoms.
Prescription Options
The pharmacist
frequently encounters patients who have faithfully and carefully followed all
directions on nonprescription products but still do not obtain adequate
relief. These patients should be referred to a board-certified allergist or
immunologist for a full evalua tion.7 Patients will usually
be given a sophisticated series of tests designed to identify the specific
allergens responsible for their symptoms. Once this has been done, the clinic
will institute a specific immunotherapy regimen to modify the biological
response to the identified allergens.10
Patients usually take weekly
injections of allergens in gradually increasing doses. The mechanism by which
this method reduces allergic rhinitis is not fully elucidated but is thought
to involve gradual stimulation of the immune system, with the resultant effect
of preventing mast cell degranulation. However, patients must be observed for
a short time following each injection to ensure that they do not experience
anaphylaxis. Improvement may not occur until six to 12 months of therapy have
elapsed, but allergists report success rates as high as 80% to 90% for some
allergens.13
There are numerous
prescription interventions for AR. Prescription second-generation
antihistamines include fexofenadine (Allegra), levocetirizine (Xyzal), and
desloratadine (Clarinex). However, even prescription antihistamines have
limited ability to combat nasal congestion, and physicians may prescribe nasal
corticosteroids to help relieve persistent congestion.10
Leukotriene receptor
antagonists such as montelukast (Singulair) or zafirlukast (Accolate) may
provide relief for some patients. Nasal cortico steroids (e.g.,
beclomethasone [Beconase AQ], budesonide [Rhinocort Aqua], fluticasone
[Veramyst], triamcinolone [Nasacort AQ], mometasone [Nasonex]), intranasal
antihistamines (e.g., azelastine [Astelin]), and intranasal anticholinergics
(e.g., ipratropium [Atrovent]) can also be important adjuncts to improve
patient well-being.13
Avoid Unproven Allergy Techniques
Chiropractors,
naturopathic "physicians," nutritional consultants, and other practitioners
may mislead patients into believing they are allergic to specific antigens
through use of an unproven diagnostic technique known as applied kinesiology
or muscle response testing.15 In the most common form,
patients are asked to stand erect, with one arm stretched out at a 90-degree
angle. The healer places a hand on the wrist of that arm and tells the patient
to resist a downward pressure. The healer then pushes down on the arm. If the
patient resists, the muscle is strong. Then the test for allergies begins. The
patient may be asked to chew or suck on a suspected allergen, place it under
the hand, or hold it in the opposite hand. The healer then presses down on the
arm again. If the patient cannot resist the pressure, he is said to be
allergic to the allergen. In other versions of this unproven technique, the
patient makes a circle with the fingers of one hand that the healer tries to
pull apart, or holds the hand against the chest while the healer tries to pull
it away. Of course, the healer will often then attempt to sell the patient
unproven remedies for the allergy, such as dietary supplements or homeopathic
nostrums of un known safety and efficacy.
There is no support in
legitimate medicine for this chiropractor-developed technique, nor is there
any support for the concept that a patient contacting an allergen suddenly
experiences weakness. The reverse is true. Patients who are allergic to poison
ivy and walk in the woods frequently contact the plant without the slightest
indication that they have done so until the dermatitis manifests. Patients
whose allergies have been "identified" using this technique must be referred
to an allergist for legitimate testing as previously described.
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Accessed May 30, 2008.
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