allergic rhinitis
allergic rhinitis
ESSENTIALS OF DIAGNOSIS
General Considerations
Allergic rhinitis is very common in the United States with population studies reporting a prevalence of ~20% (range: 14–40%)Allergic rhinitis adversely affects school and work performance, costing about $6 billion annually in the United States
Seasonal allergic rhinitis is most commonly caused by pollens and spores
Flowering shrub and tree pollens are most common in the spring, flowering plants and grasses in the summer, and ragweed and molds in the fall
Dust, household mites, air pollution, and pet dander may produce year-round symptoms, termed “perennial rhinitis
”
Clinical Findings
The symptoms of “hay fever” are similar to those of viral rhinitis but are usually persistent and may show seasonal variationNasal symptoms are often accompanied by eye irritation, pruritus, conjunctival erythema, and excessive tearing
Many patients have a strong family history of atopy or allergy
The clinician should be careful to distinguish allergic rhinitis from vasomotor (nonallergic) rhinitis
Vasomotor rhinitis is caused by increased sensitivity of the vidian nerve and is a common cause of clear rhinorrhea in elderly persons
Often patients will report that they have troubling rhinorrhea in response to numerous nasal stimuli, includ- ing warm or cold air, odors or scents, light, or particulate matter
On physical examination, the mucosa of the turbinates is usually pale or violaceous because of venous engorgement
This is in contrast to the erythema of viral rhinitis
Nasal polyps, which are yellowish boggy masses of hypertrophic mucosa, are associated with long-standing allergic rhinitis
Treatment
Intranasal CorticosteroidsIntranasal corticosteroid sprays are the mainstay of treatment of allergic rhinitis
They are more effective—and frequently less expensive—than nonsedating antihistamines, though patients should be reminded that there may be a delay in onset of relief of 2 or more weeks
Corticosteroid sprays may also shrink hypertrophic nasal mucosa and nasal polyps, thereby providing an improved nasal airway and ostiomeatal complex drainage
Because of this effect, intranasal corticosteroids are critical in treating allergy in patients prone to recurrent acute bacterial rhinosinusitis or chronic rhinosinusitis
Available preparations include beclomethasone (42 mcg/spray twice daily per nostril), flunisolide (25 mcg/spray twice daily per nostril), mometasone furoate (200 mcg once daily per nostril), budesonide (100 mcg twice daily per nostril), and fluticasone propionate (200 mcg once daily per nostril)
All are considered equally effective
Probably the most critical factors are compliance with regular use and proper introduction into the nasal cavity
In order to deliver medication to the region of the middle meatus, proper application involves holding the bottle straight up with the head tilted forward and pointing the bottle toward the ipsilateral ear when spraying
Side effects are limited, the most annoying being epistaxis (perhaps related to incorrect delivery of the drug toward the nasal septum)
Antihistamines
Antihistamines offer temporary, but immediate, control of many of the most troubling symptoms of allergic rhinitis
Effective antihistamines include nonsedating loratadine (10 mg orally once daily), desloratadine (5 mg once daily), and fexofenadine (60 mg twice daily or 120 mg once daily), and minimally sedating cetirizine (10 mg orally once daily)
Brompheniramine or chlorpheniramine (4 mg orally every 6–8 hours, or 8–12 mg orally every 8–12 hours as a sustained-release tablet) and clemastine (1
34–2
68 mg orally twice daily) may be less expensive but are usually associated with some drowsiness
The H1-receptor antagonist nasal spray azelastine (1–2 sprays per nostril daily) is also effective, but many patients object to its bitter taste
Other side effects of oral antihistamines besides sedation include xerostomia and antihistamine tolerance (with eventual return of allergy symptoms despite initial benefit after several months of use)
In such patients, typically those with perennial allergy, alternating effective antihistamines periodically can control symptoms over the long term
AdjunctiveTreatment
Measures Antileukotriene medications, such as montelukast (10 mg/day orally), alone or with cetirizine (10 mg/day orally) or loratadine (10 mg/day orally), may improve nasal rhinorrhea, sneezing, and congestionCromolyn sodium and sodium nedocromil are also useful adjunct agents for allergic rhinitis
They work by stabilizing mast cells and preventing proinflammatory mediator release
Topical agents, they have very few side effects
The most useful form of cromolyn is probably the ophthalmologic preparation
Intranasal cromolyn is cleared rapidly and must be administered four times daily for continued symptom relief, and it is not nearly as effective as inhaled corticosteroid
Intranasal anticholinergic agents, such as ipratropium bromide 0
03% or 0
06% sprays (42–84 mcg per nostril three times daily), may be helpful adjuncts when rhinorrhea is a major symptom
They are not as effective for treating allergic rhinitis but are more useful for treating vasomotor rhinitis
Avoiding or reducing exposure to airborne allergens is the most effective means of alleviating symptoms of allergic rhinitis
Depending on the allergen, this can be extremely difficult
Maintaining an allergen-free environment by covering pillows and mattresses with plastic covers, substituting synthetic materials (foam mattress, acrylics) for animal products (wool, horsehair), and removing dust-collecting household fixtures (carpets, drapes, bedspreads, wicker) is worth the attempt to help more troubled patients
Air purifiers and dust filters may also aid in maintaining an allergen-free environment
Nasal saline irrigations are a useful adjunct in the treatment of allergic rhinitis to mechanically flush the allergens from the nasal cavity
There is no clear benefit to hypertonic saline over commercially available normal saline preparations (eg, Ayr or Ocean Spray)
When symptoms are extremely bothersome, a search for offending allergens may prove helpful
This can either be done by serum radioallergosorbent test (RAST) testing or skin testing by an allergist
In some cases, allergic rhinitis symptoms are inadequately relieved by medication and avoidance measures
Often, such patients have a strong family history of atopy and may also have lower respiratory manifestations, such as allergic asthma
Referral to an allergist may be appropriate for consideration of immunotherapy
This treatment course is quite involved, with proper identification of offending allergens, progressively increasing doses of allergen(s), and eventual maintenance dose administration over a period of 3–5 years
Immunotherapy has been proven to reduce circulating IgE levels in patients with allergic rhinitis and reduce the need for allergy medications
Both subcutaneous and sublingual immunotherapy have been shown to be effective in the long-term treatment of refractory allergic rhinitis
Treatment
s are initiated at a suitable medical facility with monitoring following treatment because of the risk of anaphylaxis during dose escalation; later, sublingual immunotherapy may be administered at homeLocal reactions from subcutaneous injections are common and usually self-limited
