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Allergic rhinitis is one of the most common inflammatory disorders of the nasal mucosa. It is characterized by four major manifestations including but not limited to nasal congestion, clear rhinorrhea, sneezing, and nasal pruritis/itching. Repeated exposures and responses can have debilitating outcomes for this easily controllable and treatable condition. Awareness of the said disease can drastically reduce the risk of presentation to clinical settings with severe flares and associated complications/ comorbidities.
Allergic rhinitis tends to present with various components of systemic allergy and its presentation alongside other concurrent associations such as asthma or atopic dermatitis that share similar pathophysiology and pathogenesis with the said condition all of which require systematic identification, evaluation, and address when presenting to a clinician.1
What is the etiological association of Allergic Rhinitis?
Extensive studies of genetic association showed higher propensity in monozygotic twins and genetic loci of allergic rhinitis were isolated on Chromosome 3 & 4. 2
The following two mechanisms are found to be closely linked to etiopathogenesis:
IgE mediated:
Early phase response: IgE mediated 5-15mins of antigen exposure (Th2 cells)
Late phase response: cytokine-mediated mast cell release of substances 4-6hours after the initial response (IL4, IL13 linked)
Non-IgE mediated: eosinophilic infiltration & nasal mucosal obstruction causes hyperactivity to normal stimuli like cold air emulating allergic rhinitis symptoms 3
Classification & phenotype of Allergic Rhinitis 5
AR can be classified as either seasonal (intermittent) or perennial (chronic), with approximately the majority of cases globally being more of a mixed presentation 4 in addition to nasal symptoms, patients with AR may also present with associated allergic conjunctivitis, non-productive cough, Eustachian tube dysfunction, and chronic sinusitis.
Based on various etiological factors the following phenotypes are proposed for Allergic Rhinitis:
In 2001, ARIA (Allergic Rhinitis &its impact on asthma) classification based on frequency& severity of symptoms was given as follows 7:
Severity based
o Intermittent < 4days/week, < 4weeks per year
o Persistent >/= 4 days per week, >/= 4 weeks per year
Frequency based
o Mild: normal sleep and no impairment of daily activities, sports, leisure, and normal work at school and no troublesome symptoms
o Moderate- severe (one more item): abnormal sleep, impairment of daily activities, sports, leisure, abnormal work at school, and troublesome symptoms.
What are the aspects to be focused on in the clinical history of a patient with Allergic Rhinitis?
Symptoms to look for include Itching, sneezing, eye involvement, seasonal variation of symptoms, diurnal pattern of symptoms
Symptom triggers when indoors or outdoors and any known environmental triggers
Environmental triggers such as dust mites, pet dander, perfumes
Medications/drug-related known allergies such as beta blockers/ NSAID
Any known occupational exposure such as chalk dust in teachers, chemical factory workers
Family history of asthma or atopy or allergies of any kind
Any prior medication history and associated effectivity level and response to medications taken
Effect on the Quality of life of the patient with impact on daily activities due to allergic rhinitis
Associated comorbidities such as sinusitis, otitis media
Clinical examination
A complete nasal examination can show pale and hypertrophic inferior turbinate with clear secretions on the anterior rhinoscopy. The presence of deviated nasal septum and the presence or absence of a pale nasal polyp along with the location of the polyp must be noted. Any granulations or septal perforations must be noted. The presence of cobblestone appearance with Post-nasal drip over the Posterior pharyngeal wall is a telltale sign of lymphoid hyperplasia which is seen in allergic rhinitis. Nasal endoscopy helps to visualize the details of the nasal architecture along with polyps if any.
PNS examination for concomitant sinus involvement and chest examination to look for associated Allergic airway diseases such as asthma is necessary.
Investigations
The predominant diagnosis being history-based, Allergic Rhinitis does require some detailed investigation panel most essentially the skin prick test that helps to diagnose specific allergens. It is a quick and easy-to-perform test that can be interpreted safely in 15-20mins and contribute to the most important aspect of treatment i.e. identification of specific allergens.
Cytology of nasal secretions can be done in Non-allergic rhinitis with Eosinophilia syndrome.
Allergen-specific IgE testing helps in those where the skin prick test is contraindicated. Routine blood tests may be useful to look for any concomitant focus of infections and imaging are important to rule out any associated sinus disease e.g fungal rhinosinusitis
What complications can untreated Allergic Rhinitis lead to?
Chronic Rhinosinusitis
Image: CT Axial cut showing Hypertrophic turbinates bilaterally with mucosal edema reducing net airway space
Nasal polyposis
Image: sagittal CT of a patient with Allergic ethmoidal polyposis showing pansinusitis and soft tissue densities of ethmoidal polyps
Altered immunological parameters such as enlarged adenoids
Eustachian tube dysfunction
Concurrent asthma
Serous otitis media (SOM)
Persistent or worsening irritative cough
Eosinophilic esophagitis
Progress to anaphylaxis during allergy desensitization treatment
Treatment:
Pharmacotherapy
Antihistamines such as Chlorpheniramine, Bilastine
Corticosteroids in the form of intranasal spray such as fluticasone furoate or mometasone
Chromones such as Sodium Cromoglycate
Decongestants such as phenylephrine systemically or oxymetazoline topically as nasal drops
Anticholinergic intranasally such as ipratropium
Antileukotrienes such as Montelukast
Gross overview of guidelines for pharmacological treatment of Allergic Rhinitis 6,7 as published recently in the Indian guidelines for Allergic Rhinitis by the Association of Otolaryngologists of India in line with international standard of ARIA guidelines is as illustrated 6,7
Non- Pharmacological therapy:
Allergen avoidance
Adjunctive therapy: nasal irrigation
Sublingual Immunotherapy
Surgical management- Turbinoplasty, Submucosal diathermy, Septoplasty, FESS
Early identification and appropriate patient-tailored treatment for Allergic Rhinitis can prevent adverse outcomes and complications and significantly improve patient quality of life.
REFERENCES
1 Kakli HA, Riley TD. Allergic Rhinitis. Prim Care. 2016 Sep;43(3):465-75.
2 Tran NP, Vickery J, Blaiss MS. Management of rhinitis: allergic and non-allergic. Allergy Asthma Immunol Res. 2011 Jul;3(3):148-56.
3 Min YG. The pathophysiology, diagnosis, and treatment of allergic rhinitis. Allergy Asthma Immunol Res. 2010 Apr;2(2):65-76.
4 Skoner DP. Allergic rhinitis: definition, epidemiology, pathophysiology, detection, and diagnosis. J Allergy Clin Immunol. 2001 Jul;108(1 Suppl):S2-8.
5 Small P, Kim H. Allergic Rhinitis. Allergy Asthma ClinImmunol.2011;7 Suppl 1:S3.
6 Trans NP, Vickery J, Blaiss MS. Management of rhinitis: allergic and non-allergic. Allergy Asthma Immunol Res. 2011; 3 (3) : 148-156.
7.Min YG. The pathophysiology, diagnosis and treatment of allergic rhinitis. Allergy Asthma Immunol Res. 2010;2(2):65-76.