Allergic Rhinitis

Introduction

Rhinitis is simply inflammation of the nasal lining, characterized by

• rhinorrhoea
• nasal congestion
• sneezing, and
• itching

Most cases that present in a community pharmacy will be a viral infection or allergic in origin.

Allergic Rhinitis

Allergic rhinitis is a mucosal reaction in response to allergen exposure. The ARIA classification is based on the timing of the symptoms and is divided into intermittent or persistent.

NOTE: Priming to allergen refers to the phenomenon of increased nasal responsiveness to allergen with repeated allergen exposure.

• Patients, after a period of continuous allergen exposure, may find that they experience the same level of severity in symptoms with lower levels of allergen exposure. Similarly, symptoms will be worse than previously experienced when levels of the allergen are the same.

Conditions to Eliminate

• Infective rhinitis: Other symptoms such as cough and sore throat are much more prominent.
• Nonallergic rhinitis (vasomotor): Thought to be due to either an overactive parasympathetic nervous system response or hypoactive sympathetic nervous system response to irritants such as dry air, pollutants or strong odours.
• Rhinitis of pregnancy: Affecting nearly 10% of women during pregnancy and resolves spontaneously after childbirth.
• Nasal foreign body

Management

Before medication is started, it is clearly important to try and identify the causative allergen.

• If this can be achieved, measures to limit exposure to the allergen will be beneficial in reducing the symptoms experienced by the patient.

Sodium chloride 0.9% solution may be used as nasal irrigation in allergic rhinitis for modest symptom reduction, and to reduce the need for other drug treatment.

• Topical antihistamine (e.g. azelastine HCl) are faster acting than oral antihistamines and therefore useful for controlling breakthrough symptoms in allergic rhinitis; they are less effective than topical corticosteroids.
• Intranasal corticosteroids do not provide immediate relief of symptoms. Symptom relief usually starts within a few days, but a minimum trial of 4 weeks of consistent use is needed to properly establish efficacy.
• Severe allergic rhinitis causing very disabling symptoms despite conventional treatment may justify the use of oral corticosteroids for short period.
• Although the safety of nasal corticosteroids in pregnancy has not been established through clinical trials, only minimal amounts of nasal corticosteroids are systemically absorbed. Beclometasone dipropionate, budesonide and fluticasone are widely used in asthmatic pregnant women; fluticasone has the lowest systemic absorption when used intra-nasally.

External Links

• Next-generation Allergic Rhinitis and Its Impact on Asthma (ARIA) guidelines for allergic rhinitis based on Grading of Recommendations Assessment, Development and Evaluation (GRADE) and real-world evidence, 2019
  
• Intranasal antihistamine is superior to oral H1 antihistamine as add-on therapy to intranasal corticosteroid for treating allergic rhinitis, 2020
  
• Treatment of Allergic Rhintis, 2015