Allergic Rhinitis

Allergic Rhinitis Allergic rhinitis, a systemic anti-inflammatory disease affecting the upper respiratory system with prominent nasal symptoms in response to second exposure to allergens, it is a worldwide problem that affects adults and children. Allergic rhinitis is triggered by indoor and outdoor environmental allergens. Common outdoor aeroallergens (airborne environmental allergens) include pollen and mold spores, pollutants (e.g., ozone and diesel exhaust particles) are considered environmental triggers and are becoming more of a concern in highly populated areas. Common indoor aeroallergens include house dust mites, cockroaches, mold spores, cigarette smoke, and pet dander. Occupational aeroallergens include the following: wool ,dust, latex, resins, organic dusts (e.g., flour) Symptoms of allergic rhinitis generally begin after the second year of life, and the disease is prevalent in children and adults ages 18-64 years. After age 65 years, the number of cases decreases. The pathogenesis of allergic rhinitis is complex, involving numerous cells and inflammatory mediators, and consists of four phases: First is the sensitization phase, which occurs on initial allergen exposure. The allergen stimulates IgE production. Second is the early phase, occurring within minutes of subsequent allergen exposure. The early phase consists of rapid release of preformed mast cell mediators (e.g., histamine and proteases), as well as the production of additional mediators (e.g., prostaglandins,, leukotrienes, and neuropeptides). The third phase is cellular recruitment where the circulating leukocytes, especially eosinophils, are attracted to the nasal mucosa and release more inflammatory mediators. Fourth is the late phase, which begins 24 hours after allergen exposure series of allergic symptoms`are then presented including sneezing ,nasal congestion ,rhinorrhea ,itching ,red and watery eyes. Risk factors for developing allergic rhinitis include family history of atopy (allergic disorders) in one or both parents; filaggrin (skin barrier protein) gene mutation; elevated serum IgE greater than 100 IU/mL Allergic rhinitis has been classified as seasonal allergic rhinitis (“hay fever”) usually in late summer or spring , perennial allergic rhinitis occurs through out the year .

New classifications , intermittent allergic rhinitis (IAR) occurs less than 4 days or less than 4 weeks per year and persistent allergic rhinitis (PER)more than 4 days or more than 4 weeks per year. Classification of Allergic Rhinitis to sever, moderate and mild is according to duration of symptoms, impairment of sleep; impairment of daily activities. There is another type of rhinitis is called non allergic rhinitis.

Causes of non allergic rhinitis Hormonal

Pregnancy, puberty, thyroid disorders

Infectious rhinitis

a)acute sinusitis viral infection last up to 10 days b)chronic sinusitis it is bacterial infection lasts up to12 weeks

Environmental or occupational rhinitis Drug Induced

strong odours or cold air Cocaine, betablockers, ACEIs, chlorpromazine, clonidine, reserpine, hydralazine, oral contraceptives, aspirin or other NSAIDs, overuse of topical decongestants

Structural

Septal deviation, adenoid hypertrophy

Traumatic

Recent facial or head trauma

Gustatory rhinitis

hot or spicy foods

Acute complications of allergic rhinitis include sinusitis and otitis media with effusion.

Chronic complications include nasal polyps, sleep apnea, sinusitis, and hyposmia(diminished sense of smell).

Treatment of Allergic Rhinitis Allergic rhinitis cannot be cured. The goals of therapy are to reduce symptoms and improve the patient’s functional status and sense of well being.

General Treatment Approach Allergic rhinitis is treated in three steps: allergen avoidance, pharmacotherapy, and immunotherapy. Health care providers should maximize each step before going on to the next intervention. Patient education is an important part of all three steps

Non pharmacologic Therapy Allergen avoidance is the primary non pharmacologic measure for allergic rhinitis House dust mites ‫( عته الغبار‬Dermatophagoides spp.), found in warm, humid environments. Avoidance strategies, targeted at 1)reducing the mite population in mattress,pillows 2) lowering the household humidity to less than 40%, 3)applying acaricides, and 4)reducing mite harboring dust by removing carpets, upholstered furniture, stuffed animals, and bookshelves from the patient’s bedroom. Mold is challenging to eliminate due to ability to grow in wall cracks ,carpet fibers and difficult to reach areas where spores are the reproductive unit of and other fungi. We are surrounded by mold spores indoors and outdoors . Indoor mold exposure is minimized by lowering household humidity, removing houseplants, venting food preparation areas and bathrooms, repairing damp basements, and frequently applying fungicide to obviously moldy areas. Cat derived allergens are small and light, and they stay airborne for several hours. Cat allergens can be found in the house months after the cat is removed.

Ventilation systems with high efficiency particulate air (HEPA) filters remove pollen, mold spores, and cat allergens from household air. Filters need to be changed regularly to maintain effectiveness. HEPA filters are also found in some vacuum cleaners. Weekly vacuuming of carpets, drapes, and upholstery with a HEPA filter equipped vacuum cleaner may help reduce household allergens.

Pharmacological Therapy plan 1)Intranasal corticosteroids 2)Oral antihistamincs 3)Oral leukotrien receptor antagonist 4)Intranasal antihistaminics 5)Decongestants 6)Intranasal mast cell stabilizers 7)Intranasal anticholinergics 8)combination therapy

Intranasal corticosteroids (INCS) also known as glucocorticoids have been shown to be the most effective treatment for most symptoms of allergic rhinitis such as itching, rhinitis, sneezing, and congestion as they inhibit multiple cell types and mediators, including histamine, and so effectively stop the “allergic cascade.

First generation INSCS Beclomethasine(Beclo) ,triamcinolone acetonide (Nasacort),budesonide (rhinocort aqua) and flusenolide(Nastarel) are more bioavailable and more systemic side effects

Second generation INCS fluticasone propionate (Flonase) and fluticasone furoate(Avamys) ,momentasone(nasonex) are less bioavailable and limited systemic side effects . FDA in 2012 has approved beclomethasone(Qnasal) dry nasal aerosol to be the first non aquous nasal formulation available. Complete symptom control may not be seen for up to 1 week. Patients should be instructed to shake the bottle well before each use and discard the product after a total of 60 or 120 doses, depending on which size was purchased, even if the bottle does not feel completely empty. Oral Antihistamines Antihistamines are indicated for relief of symptoms of allergic rhinitis (e.g., itching, sneezing, and rhinorrhea) and other types of immediate hypersensitivity reactions

They are classified as sedating (first generation, nonselective i.e. brompheniramine , chlorpheniramine , promethazine) or non sedating (second generation, peripherally selective i.e.acrivastine,ebastine, loratadine,cetrizine),(third generation i.e. levocetrizine ,desloratidine,fexofenadine) Sedating antihistamines expose patients to risks of anticholinergic effects i.e. dryness of the eyes and mucous membranes (mouth, nose, vagina); blurred vision; urinary retention; constipation; and reflex tachycardia in addition to sedation and impaired performance (e.g., impaired driving performance, poor work performance) and so should be used with caution. Antihistamines compete with histamine at central and peripheral histamine (H1)receptor sites, preventing the histamine receptor interaction and subsequent mediator release. In addition, second generation antihistamines inhibit the release of mast cell mediators and may decrease cellular recruitment. Onset of action:15 to 30 minutes . It approved by FDA as safe for children above 2 years. Loratadine is the nonprescription antihistaminic of choice, followed by fexofenadine and Cetirizine] Oral leukotriene receptor antagonist Montelukast is the only approved oral leukotriene receptor antagonist for use in seasonal and perennial allergic rhinitis. It is particulary useful for patients with coexisting asthma because it reduces bronchospasm and attenuates inflammatory response.

Intranasal antihistamines i.e. Azelastine They ara targeted delivery drugs increasing dosage to nasal tissues They are not recommended as first line therapy due to high cost ,less effective and more adverse effects than INCS Decongestants Congestion is a common allergic rhinitis symptom controllable with systemic decongestants or short term(≤5 days) topical nasal decongestants. i.e. pseudoephedrine ,oxymetazoline and phenylepherine. Topical decongestants develop rebound congestion if used more 5 days so patient counseling should be verified. Intranasal mast cell stabilizers

Cromolyn sodium is thought to work by blocking the influx of calcium into mast cells thereby preventing mediator release It is useful for patients with specific known allergy and are planning to be in contact with that allergen so it is given 30 minutes before allergen exposure. Intra nasal anticholinergics Ipratropium(atrovent) It has antisecretory properties inhibiting secretions from nasal lining mucosa so used in relieving rhinorrhia and congestion symptoms Nasal wetting agents nasal irrigation with warm saline (isotonic or hypertonic) may relieve nasal mucosal irritation and dryness.That process also aids in the removal of dried or thick mucus from the nose. It is only for the symptoms not treating therapy. Immunotherapy Subcutaneous immunotherapy SCIT, commonly called allergy shots is a unique way of treating allergies and asthma. Medications treat the symptoms of allergies while immunotherapy changes the way a person’s immune system is reacting to the environment. First allergen skin testing identifies a person’s allergic triggers. A personalized vaccine is then formulated using all natural protein extracts. This extract is then administered subcutaneously with small doses by developing immunity or tolerance to the allergen.

Allergy shot treatment involves two phases. The first phase involves frequent injections of increasing amounts of allergen extract. This is followed by a maintenance phase, during which the injections are given about once a month. Another form of allergy immunotherapy was recently approved in the United States called sublingual immunotherapy (SLIT) allergy tablets. FDA approved four allergy tablets products. Two are directed at different kinds of grass pollen, one is for dust mites and one is for short ragweed.

Anti-immunoglobulin E antibody Omalizumab (Xolair) anti-immunoglobulin E antibody approved for asthma and had shown effectiveness in reducing nasal symptoms and improving quality of life. It only limitation yet is its high cost.

References

2015 American academy of otolaryngology-head and neck surgery foundation(AAOHNSF) guidelines for allergic rhinitis. Handbook of non prescription drugs 28207208800468 gz8537750