Merck Manual

Please confirm that you are a health care professional

honeypot link

Allergic Rhinitis


Peter J. Delves

, PhD, University College London, London, UK

Last full review/revision Oct 2020| Content last modified Sep 2022
Click here for Patient Education
Topic Resources

Allergic rhinitis is seasonal or perennial itching, sneezing, rhinorrhea, nasal congestion, and sometimes conjunctivitis Allergic Conjunctivitis Allergic conjunctivitis is an acute, intermittent, or chronic conjunctival inflammation usually caused by airborne allergens. Symptoms include itching, lacrimation, discharge, and conjunctival... read more Allergic Conjunctivitis , caused by exposure to pollens or other allergens. Diagnosis is by history and occasionally skin testing. First-line treatment is with a nasal corticosteroid (with or without an oral or a nasal antihistamine) or with an oral antihistamine plus an oral decongestant.

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

  • Spring: Tree pollens (eg, oak, elm, maple, alder, birch, juniper, olive)

  • Summer: Grass pollens (eg, Bermuda, timothy, sweet vernal, orchard, Johnson) and weed pollens (eg, Russian thistle, English plantain)

  • Fall: Other weed pollens (eg, ragweed)

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 Nonallergic Rhinitis Rhinitis is inflammation of the nasal mucous membrane, with resultant nasal congestion, rhinorrhea, and variable associated symptoms depending on etiology (eg, itching, sneezing, watery or purulent... read more include infectious, vasomotor, drug-induced (eg, aspirin- or nonsteroidal anti-inflammatory drug [NSAID]–induced), and atrophic rhinitis.

Symptoms and Signs of Allergic 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 Etiology Etiology and nasal polyps Nasal Polyps Nasal polyps are fleshy outgrowths of the nasal mucosa that form at the site of dependent edema in the lamina propria of the mucous membrane, usually around the ostia of the maxillary sinuses... read more Nasal Polyps may develop.

Signs include edematous, bluish-red nasal turbinates, and, in some cases of seasonal allergic rhinitis, conjunctival injection and eyelid edema.

Diagnosis of Allergic Rhinitis

  • Clinical evaluation

  • Occasionally skin testing, allergen-specific serum IgE tests, or both

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 Specific tests Allergic (including atopic) and other hypersensitivity disorders are inappropriate or exaggerated immune reactions to foreign antigens. Inappropriate immune reactions include those that are... read more 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 Specific tests 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 Granulomatosis with Polyangiitis (GPA) Granulomatosis with polyangiitis is characterized by necrotizing granulomatous inflammation, small- and medium-sized vessel vasculitis, and focal necrotizing glomerulonephritis, often with crescent... read more Granulomatosis with Polyangiitis (GPA) , and sarcoidosis Sarcoidosis Sarcoidosis is an inflammatory disorder resulting in noncaseating granulomas in one or more organs and tissues; etiology is unknown. The lungs and lymphatic system are most often affected, but... read more Sarcoidosis .

Treatment of Allergic Rhinitis

  • Antihistamines

  • Decongestants

  • Nasal corticosteroids

  • For seasonal or severe refractory rhinitis, sometimes desensitization

Treatment of seasonal and perennial allergic rhinitis is generally the same, although attempts at removal or avoidance of allergens Prevention Allergic rhinitis is seasonal or perennial itching, sneezing, rhinorrhea, nasal congestion, and sometimes conjunctivitis, caused by exposure to pollens or other allergens. Diagnosis is by history... read more (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

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.


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

  • Symptoms are severe.

  • The allergen cannot be avoided.

  • Drug treatment is inadequate.

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

  • For adults: One 300-IR (index of reactivity) tablet daily

  • For patients aged 10 to 17 years: One 100-IR tablet on day 1, two 100-IR tablets simultaneously on day 2, then the adult dose from day 3 onward

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.

Prevention of Allergic Rhinitis

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.

Key Points

  • 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.

Drugs Mentioned In This Article

Drug Name Select Trade
Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
quiz link

Test your knowledge

Take a Quiz!