(See also Overview of Allergic and Atopic Disorders.)
Allergic rhinitis may occur seasonally or throughout the year (as a form of perennial rhinitis). Seasonal rhinitis is usually allergic. At least 25% of perennial rhinitis is nonallergic.
Seasonal allergic rhinitis (hay fever) is most often caused by plant allergens, which vary by season. Common plant allergens include
Causes also differ by region, and seasonal allergic rhinitis is occasionally caused by airborne fungal (mold) spores.
Perennial rhinitis is caused by year-round exposure to indoor inhaled allergens (eg, dust mite feces, cockroaches, animal dander) or by strong reactivity to plant pollens in sequential seasons.
Allergic rhinitis and asthma frequently coexist; whether rhinitis and asthma result from the same allergic process (one-airway hypothesis) or rhinitis is a discrete asthma trigger is unclear.
The numerous nonallergic forms of perennial rhinitis include infectious, vasomotor, drug-induced (eg, aspirin- or nonsteroidal anti-inflammatory drug [NSAID]–induced), and atrophic rhinitis.
Patients have itching (in the nose, eyes, or mouth), sneezing, rhinorrhea, and nasal and sinus obstruction. Sinus obstruction may cause frontal headaches; sinusitis is a frequent complication. Coughing and wheezing may also occur, especially if asthma is also present.
The most prominent feature of perennial rhinitis is chronic nasal obstruction, which, in children, can lead to chronic otitis media; symptoms vary in severity throughout the year. Itching is less prominent than in seasonal rhinitis. Chronic sinusitis and nasal polyps may develop.
Signs include edematous, bluish-red nasal turbinates, and, in some cases of seasonal allergic rhinitis, conjunctival injection and eyelid edema.
Allergic rhinitis can almost always be diagnosed based on history alone. Diagnostic testing is not routinely needed unless patients do not improve when treated empirically; for such patients, skin tests are done to identify a reaction to pollens (seasonal) or to dust mite feces, cockroaches, animal dander, mold, or other antigens (perennial), which can be used to guide additional treatment.
Occasionally, skin test results are equivocal, or testing cannot be done (eg, because patients are taking drugs that interfere with results); then, an allergen-specific serum IgE test is done.
Eosinophilia detected on nasal smear plus negative skin tests suggests aspirin sensitivity or nonallergic rhinitis with eosinophilia (NARES).
Nonallergic perennial rhinitis is usually also diagnosed based on history. Lack of a clinical response to treatment for assumed allergic rhinitis and negative results on skin tests and/or an allergen-specific serum IgE test also suggest a nonallergic cause; disorders to consider include nasal tumors, enlarged adenoids, hypertrophic nasal turbinates, granulomatosis with polyangiitis, and sarcoidosis.
Treatment of seasonal and perennial allergic rhinitis is generally the same, although attempts at removal or avoidance of allergens (eg, eliminating dust mites and cockroaches) are recommended for perennial rhinitis. For seasonal or severe refractory rhinitis, desensitization immunotherapy may help.
The most effective first-line drug treatments are
Nasal corticosteroids with or without oral or nasal antihistamines
Oral antihistamines plus oral decongestants (eg, a sympathomimetic such as pseudoephedrine)
Less effective alternatives include nasal mast cell stabilizers (eg, cromolyn) given 3 or 4 times a day, the nasal H1 blocker azelastine 1 to 2 puffs twice a day, and nasal ipratropium 0.03% 2 puffs every 4 to 6 hours, which relieves rhinorrhea.
Nasal drugs are often preferred to oral drugs because less of the drug is absorbed systemically.
Inhaled Nasal Corticosteroids
Inhaled Nasal Mast Cell Stabilizers
Intranasal saline, often forgotten, helps mobilize thick nasal secretions and hydrate nasal mucous membranes; various saline solution kits and irrigation devices (eg, squeeze bottles, bulb syringes) are available over the counter, or patients can make their own solutions.
Desensitization immunotherapy may be more effective for seasonal than for perennial allergic rhinitis; it is indicated when
First attempts at desensitization should begin soon after the pollen season ends to prepare for the next season; adverse reactions increase when desensitization is started during the pollen season because the person’s allergic immunity is already maximally stimulated.
Sublingual immunotherapy using 5–grass pollen sublingual tablets (an extract of 5 grass pollens) can be used to treat grass pollen-induced allergic rhinitis. Dosage is
The first dose is given in a health care setting and patients should be observed for 30 minutes after administration because anaphylaxis may occur. If the first dose is tolerated, patients can take subsequent doses at home. Treatment is initiated 4 months before the onset of each grass pollen season and maintained throughout the season.
Sublingual immunotherapy using either ragweed pollen or house dust mite allergen extracts can be used to treat allergic rhinitis induced by these allergens.
Patients with allergic rhinitis should carry a prefilled, self-injecting epinephrine syringe.
Montelukast, a leukotriene blocker, relieves allergic rhinitis symptoms but, due to a risk of mental health adverse effects (eg, hallucination, obsessive-compulsive disorder, suicidal thoughts and behavior), montelukast should be used only when other treatments are not effective or not tolerated.
Omalizumab, an anti-IgE antibody, is under study for treatment of allergic rhinitis but will probably have a limited role because less expensive, effective alternatives are available.
Treatment of NARES (nonallergic rhinitis with eosinophilia) is nasal corticosteroids.
Treatment of aspirin sensitivity is avoidance of aspirin and nonselective nonsteroidal anti-inflammatory drugs (which can cross-react with aspirin), plus desensitization and leukotriene blockers as needed.
For perennial allergies, triggers should be removed or avoided if possible. Strategies include the following:
Removing items that collect dust, such as knickknacks, magazines, books, and soft toys
Using synthetic fiber pillows and impermeable mattress covers
Frequently washing bed sheets, pillowcases, and blankets in hot water
Frequently cleaning the house, including dusting, vacuuming, and wet-mopping
Removing upholstered furniture and carpets or frequently vacuuming them
Replacing draperies and shades with blinds
Exterminating cockroaches to eliminate exposure
Using dehumidifiers in basements and other poorly aerated, damp rooms
Using high-efficiency particulate air (HEPA) vacuums and filters
Avoiding food triggers
Limiting pets to certain rooms or keeping them out of the house
Adjunctive nonallergenic triggers (eg, cigarette smoke, strong odors, irritating fumes, air pollution, cold temperatures, high humidity) should also be avoided or controlled when possible.
Seasonal rhinitis is usually an allergic reaction to pollens.
Patients with allergic rhinitis may have cough, wheezing, frontal headache, sinusitis, or, particularly in children with perennial rhinitis, otitis media.
Diagnosis of allergic rhinitis is usually based on the history; skin tests and sometimes an allergen-specific serum IgE test are needed only when patients do not respond to empiric treatment.
Try nasal corticosteroids first because they are the most effective treatment and have few systemic effects.