Wed. Aug 3rd, 2022
    Allergic rhinitis

    Allergic Rhinitis

    Allergic rhinitis is manifested by pruritus, sneezing, rhinorrhea, nasal congestion, seasonal or permanent, and sometimes conjunctivitis, caused by exposure to pollens or other allergens. Diagnosis is based on history and sometimes skin testing. First-line treatment is nasal corticosteroids (with or without an oral or nasal antihistamine) or an oral antihistamine plus an oral decongestant.

    Allergic rhinitis can occur seasonally or throughout the year (as persistent rhinitis). Seasonal rhinitis is usually allergic. At least 25% of persistent rhinitis is not allergic.

    Seasonal allergic rhinitis (hay fever) is most often caused by plant allergens, which vary by season. Common plant allergens include the following:

    • In spring: tree pollens (eg, oak, elm, maple, alder, birch, juniper, olive)
    • In summer: grass pollens (eg, rosehip, timothy, quackgrass, cocksfoot, Johnson) and herb pollens in summer (eg, Russian thistle, English plantain)
    • In fall: other grass pollens (eg, ragweed)

    The causes also differ by region and allergic rhinitis is sometimes due to airborne mycotic spores.

    Persistent rhinitis results from year-round exposure to inhaled allergens in the home (eg, feces dust mites, cockroaches, bits of animal hair or feathers) or strong reactivity to plant pollens during several seasons.

    Allergic rhinitis and asthma often coexist; it is not yet known whether rhinitis and asthma result from the same allergic process (single airway hypothesis) or whether rhinitis is a discrete trigger of asthma.

    The many forms of persistent nonallergic rhinitis include infectious, vasomotor, drug-induced (eg, NSAID- or aspirin-induced) rhinitis, and atrophic rhinitis.

    Symptoms of allergic rhinitis

    The patient presents with pruritus (of the nose, eyes or mouth), sneezing, rhinorrhea and nasal or sinus obstruction. Sinus obstruction can lead to frontal headaches; sinusitis is a frequent complication. Coughing and wheezing may also occur, particularly if asthma is also present.

    The prominent feature of persistent rhinitis is chronic nasal obstruction, which in children can lead to chronic otitis media; symptoms vary in severity over the year. Pruritus is less important than in seasonal rhinitis. Chronic sinusitis and nasal polyps may develop.

    Symptoms include turbinate edema, and, in some cases of seasonal allergic rhinitis, conjunctival erythema and eyelid edema.

    Diagnosis of allergic rhinitis

    • Clinical assessment
    • Sometimes skin tests and/or allergen-specific IgE tests

    Allergic rhinitis can almost always be diagnosed by questioning alone. Diagnostic tests are not routinely needed unless patients do not improve when treated empirically; in these patients skin tests are done to reveal a reaction to pollens (seasonal rhinitis) or dust mite faeces, cockroaches, fragments of animal hair and feathers, molds or other antigens ( persistent rhinitis) and can be used to decide on another treatment.

    Sometimes skin tests give equivocal results, or the tests cannot be done (eg, because patients are taking drugs that interfere with the results); in this case, a specific IgE test in the serum is carried out.

    Eosinophilia detected on a nasal swab smear with negative skin tests suggests aspirin sensitivity or nonallergic rhinitis with eosinophilia.

    Diagnosis of perennial nonallergic rhinitis is usually also based on history. Lack of clinical response to treatment for suspected allergic rhinitis and negative skin test and/or allergen-specific serum IgE test results also suggest a non-allergic cause; disorders to consider include nasal tumors, enlarged adenoids, hypertrophic nasal turbinates, granulomatosis with polyangiitis, and sarcoidosis.

    • Treatment of allergic rhinitis
    • Antihistamines
    • Decongestants
    • Nasal corticosteroids

    In case of severe or refractory seasonal rhinitis, sometimes desensitization
    Treatment for seasonal and persistent allergic rhinitis is generally the same, although attempts to suppress or avoid allergens (eg, by eliminating dust mites and cockroaches) are recommended in cases of perennial rhinitis. For severe refractory or seasonal rhinitis, desensitization immunotherapy may be helpful.

    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 solutions include nasal mast cell stabilizers (eg, cromolyn and nedocromil) given 3 or 4 times a day, the H1 blocker azelastine 1 to 2 puffs twice a day, and ipratropium nasal 0.03%, 2 puffs every 4 to 6 hours, which relieves rhinorrhea.

    Nasal medications are often preferred over oral medications because less of the drug is absorbed systemically.

    The often overlooked intranasal saline solution helps mobilize thick nasal secretions and hydrates the nasal mucous membranes; various saline solution kits and irrigation devices (eg, squeeze bottles, bulb syringes) are available over-the-counter, or patients can develop their own solutions.

    Desensitization immunotherapy may be more effective in seasonal allergic rhinitis than in the perennial form; it is indicated when:
    • The symptoms are serious.
    • The allergen cannot be avoided.
    • Drug treatment is insufficient.

    Initial attempts at desensitization should begin shortly after the end of the pollen season to prepare for the following season; adverse effects increase when desensitization is started at the beginning of the season, since the person’s allergic immunity is already stimulated to the maximum.

    Sublingual immunotherapy with sublingual tablets containing 5 grass pollens (an extract of 5 grass pollens) can be used to treat grass pollen-induced allergic rhinitis. Dosage:
    • For adults: one 300-IR (reactivity index) tablet per day.
    • In patients aged 10 to 17 years: one tablet of 100 IR on D1, two tablets of 100 IR simultaneously on D2, then the adult dose on D3 on and beyond

    The first dose is given in a medical setting and patients should be observed for 30 minutes after administration due to the risk of anaphylaxis. If the first dose is tolerated, patients can take further doses at home. Treatment is initiated 4 months before the start of each grass pollen season and is maintained throughout the season.

    Sublingual immunotherapy using ragweed or dust mite allergen extracts can be used to treat allergic rhinitis induced by these allergens.

    Patients with allergic rhinitis should carry a pre-filled epinephrine self-injection syringe with them.

    Montelukast, a leukotriene blocker, relieves symptoms of allergic rhinitis but, because of the risk of adverse mental health effects (eg, hallucination, obsessive-compulsive disorder, suicidal thoughts and behaviors), montelukast should only be used when other treatments are not effective or not tolerated.

    Omalizumab, an anti-IgE antibody, is being studied for the treatment of allergic rhinitis, but will probably have a limited role because less expensive effective solutions are available.

    The treatment of non-allergic rhinitis with eosinophilia uses nasal corticosteroids.

    Treatment of aspirin allergy is based on avoidance of aspirin and non-selective NSAIDs (which can cross-react with aspirin), plus desensitization and antileukotrienes as needed.

    Prevention of allergic rhinitis

    In perennial allergies, triggers should be removed or avoided if possible. Strategies include:

    • Dispose of objects that accumulate dust, such as trinkets, magazines, books and stuffed animals
    • The use of synthetic fiber pillows and waterproof mattress protectors
    • Frequent washing of bed sheets, pillowcases and blankets in hot water
    • Frequent house cleaning, including dusting, vacuuming and damp mopping
    • Remove upholstered furniture and rugs or vacuum them frequently
    • Replace curtains with blinds
    • The extermination of cockroaches to eliminate exposure
    • The use of dehumidifiers in basements and other poorly ventilated and damp rooms
    • The use of vacuum cleaners and high-efficiency particulate filters
    • Avoidance of responsible foods
    • Restricted access of pets to certain rooms or keeping them outside
    • Additional non-allergenic triggers (eg, cigarette smoke, strong odors, irritating fumes, air pollution, cold temperatures, high humidity) should also be avoided or controlled when possible.

    Key points of allergic rhinitis

    Seasonal rhinitis is usually an allergic reaction to pollens.
    Patients with allergic rhinitis may present with cough, wheezing, frontal headache, sinusitis or, particularly in children with persistent rhinitis, otitis media.
    Diagnosis of allergic rhinitis is usually based on history; skin testing and sometimes serum allergen-specific IgE testing are needed, but 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.

    Sources: PinterPandai, NHS UK, HealthLine, Cleveland Clinic, Family Doctor

    Photo credit: https://www.myupchar.com/en / Wikimedia Commons (CC BY-SA 4.0)