ALLERGIC RHINITIS
Definition: Allergic Rhinitis is an IgE mediated hypersensitivity disease of the nasal mucous membrane, characterized by sneezing, nasal blockage and nasal discharge.
Prevalence:
- Indonesia, Romania and Greece had a low prevalence of allergic rhinitis (<5%).
- United Kingdom, Australia and New Zealand had a high prevalence of rhinitis (15–20%).
Aetiology:
- Environmental: Cold environment triggers off allergy.
- Hereditary: There are higher chances if both parents have allergy to certain allergens.
- Age: Common in the 2nd and 3rd decade.
- Psychological stress: Known to precipitate already existing allergy.
Pathophysiology:
Common allergens:
Symptoms:
- Dust, pollen.
- Food: Eggs, prawns, pineapple etc.
- Fungi: Cladosporium, Aspergillus.
- Irritating fumes, vehicular exhaust.
- Cosmetics, synthetic clothes, shampoo.
- Intestinal helminths.
Symptoms:
- Nasal irritation and obstruction.
- Sneezing episodes.
- Watery discharge.
- Anosmia.
Signs:
- Nasal signs like transverse nasal crease on mid dorsum of nose due to constant upward rubbing of nose (allergic salute). On anterior rhinoscopy there is turbinate hypertrophy. Ethmoidal polyps may be present in long standing untreated allergy patients.
- Ocular signs like lid oedema, cobble- stone and congestion of conjunctiva, dark circles under eyes (allergic shiners).
- Otologic signs like retracted tympanic membrane or otitis media with effusion due to eustachian tube blockage.
- Granular pharyngitis.
- Laryngeal signs include oedema of vocal cords.
Investigations:
- Detail history and examination-
- A history suggesting asthma such as wheeze or nighttime cough may necessitate examination of the chest or referral to a respiratory physician.
- A general examination of the patient may reveal other signs of atopic disease such as eczema or allergic conjunctivitis. Sometimes an allergic crease may be seen on the patient’s nose.
- Anterior rhinoscopy will allow an assessment to be made of the color and state of the nasal mucosa and to see whether it is swollen and causing obstruction.
- Endoscopic examination will allow polyps and other nasal disease to be excluded.
- Blood count – eosinophilia.
- CT Scan PNS.
- Nasal smear.
- Radio-Allergo Sorbent Test (RAST)-
- This will normally be either a skin prick test (SPT) or measurement of specific IgE in the blood.
- The method of skin prick testing involves the use of a small lancet to introduce an allergen into the skin. If the patient is sensitized to the allergen then IgE sensitized mast cells will degranulate and cause a wheal and flare reaction in the skin.
- Negative (saline) and positive (histamine) controls are also used to rule out dermographism and non–reactivity respectively.
- If the negative control shows a reaction or the positive control shows no reaction then blood IgE levels should be measured.
- If an oral antihistamine has been taken in the preceding 7–10 days then the positive control may not react.
- A positive reaction is noted by a wheal size 2mm or greater than the negative control.
Management:
i. The goal of rhinitis treatment is to prevent or reduce the symptoms caused by the inflammation of affected tissues.
ii. Avoidance of allergen is a very important step. It is easy to avoid if the allergen is single. Avoid from dust, pollen, specific food which is allergic, pets etc.
iii. Antihistamine drugs
- The symptoms of rhinorrhoea, sneezing ,nasal and eye itching are histamine driven and antihistamines are the first-line treatment for these symptoms.
- The older first-generation antihistamines (chlorphenamine, diphenhydramine) are rarely used now due to their sedative effects.
- Second generation oral antihistamines such as loratadine and cetirizine are non-sedating, safe for long-term use and can be used for children. They have a rapid onset of action (usually less than an hour) and give good symptomatic relief.
- Bilastine is a new second generation H1-antihistamine recently approved for the symptomatic treatment of allergic rhinitis and chronic urticaria. Bilastine 20 mg once daily is as efficacious as other non-sedating antihistamines in allergic rhinoconjunctivitis and chronic urticaria.
- Third-generation antihistamines such as levocetirizine, desloratadine and fexofenadine have increased efficacy with fewer adverse drug reactions. Fexofenadine is most preferred due to low risk of any cardiac arrhythmias.
- Topical antihistamines (for example azelastine) may be used intranasally to achieve rapid symptom control and can be combined with a topical nasal steroid.
iv. Intranasal corticosteroids
- Glucocorticoids are the most effective treatment for allergic rhinoconjunctivitis. However, they may not be very effective in active rhinorrhoea
- Topical use in the form of a spray or drops (example fluticasone, mometasone, beclomethasone) is preferred to oral use to reduce side effects.
- Intra-nasal application allows a high concentration of the active drug to be delivered to the nasal mucosa with minimal systemic absorption. They reduce all symptoms of allergic rhinitis and ocular symptoms and are the first line treatment of choice in patients who complain of nasal blockage.
- As steroids have an effect on the production of pro-inflammatory mediators within the cell nucleus their effect is slow to occur and long lasting.
- Minor growth retardation has been noted in children treated with intranasal beclomethasone.
v. Systemic Glucocorticoids
- Oral steroids may occasionally be useful in patients with severe symptoms to allow reduction of mucosal swelling and subsequent use of topical medications are given.
- Prednisolone 20–40 mg/day is normally sufficient.
vi. Leukotriene receptor antagonists:
- They include montelukast, pranlukast and zafirlukast. Cysteinyl leukotrienes cause bronchoconstriction, increase vascular permeability and attract inflammatory cells. Leukotriene receptor antagonist antagonize the action of leukotriene.
- Montelukast is used regularly to prevent the wheezing and shortness of breath caused by asthma and decrease the number of asthma attacks. Montelukast is also used before exercise to prevent breathing problems during exercise (bronchospasm). This medication can help decrease the number of times you need to use your rescue inhaler.
vii. Sodium cromoglycate
- It stabilizes the mast cells and prevents them from degranulation despite the formation of IgE-antigen complex.
- Sodium cromoglycate nasal spray has modest effects on rhinitis symptoms but must be used four times daily, which limits compliance.
- It has no major side effects and can be given to young children.
- Cromoglycate eye drops can be effective against ocular itching.
viii. Decongestant
- Topical (e.g. xylometazoline) and systemic decongestants (e.g. pseudoephedrine) are available and have a place in allergic rhinitis management.
- The topical decongestants are more effective and have a more rapid onset of action. They reduce nasal obstruction and may allow access of a topical steroid into an otherwise obstructed nose.
- Their adverse effect is of rebound vasodilation when their use is stopped leading to a worsening of symptoms. Rhinitis medicamentosa ca occur with longer term use.
- A maximum length of treatment of 7–10 days therefore is advised.
- Systemic decongestants may also have side effects such as insomnia, tachycardia and tremor.
ix. Ipratropium
- Topical ipratropium bromide spray is effective at controlling watery rhinorrhea and can be a useful addition to a topical steroid.
- Side effects include prostatic symptoms and worsening of glaucoma.
x. Nasal douching
- Saline nasal douches help with symptom control and can physically remove an allergen from the nasal mucosa. The saline douching can be combined with budesonide. Usually given when pollen levels are high and post -operative patients.
xi. Anti-IgE
- Omalizumab is a monoclonal antibody that binds to circulating IgE preventing it from binding to mast cells and causing degranulation.
- Omalizumab reduces all nasal symptoms and improves asthma control but has the risk of causing anaphylaxis and is expensive. It is administered by monthly injection.
- Currently it is recommended only for patients with severe allergic asthma with or without rhinitis symptoms.
- It also termed desensitization treatment involves administering doses of allergens to accustom the body to substances that are generally harmless (pollen, house dust mites), thereby inducing specific long-term tolerance.
- Allergen immunotherapy is the only treatment that alters the disease mechanism.
- Immunotherapy can be administered orally (as sublingual tablets or sublingual drops), or by injections under the skin (subcutaneous).
- Subcutaneous immunotherapy is the most common form and there is evidence supporting its effectiveness.
xiii. Surgical treatment
- Surgery cannot cure allergy but can give relief of nasal blockage if other methods fail.
- Reduction of submucosal fibrotic tissue on the inferior turbinates may improve the airway and allow access for topical nasal steroids.
- If the nose remains congested even after a decongestant then surgery should be considered as the mucosal swelling may be chronic.
- Polypoidal mucosa may also be found in some patients with severe allergic rhinitis and occasionally this needs to be removed.
- Treatment includes Radiofrequency ablation of the inferior turbinate, Turbinoplasty, Septal correction, polypectomy, FESS, Vidian Neurectomy.
We Are Always Ready to Help You.
Book An Appointment
