Allergic rhinitis (AR) is an atopic (hypersensitivity) disease presenting with symptoms of sneezing, nasal congestion, clear rhinorrhoea, and nasal pruritis (Akhouri and House, 2023). AR affects one in six individuals and is associated with significant morbidity, loss of productivity, and healthcare costs (Akhouri and House, 2023). In the early phase, AR is an immunoglobulin (Ig) E-mediated response against inhaled allergens that cause inflammation driven by type 2 helper (Th2) cells (Skoner, 2001). Within five to 15 minutes of exposure to an antigen, the initial response occurs resulting in the degranulation of host mast cells (Skoner, 2001). A variety of pre-formed and newly synthesized mediators are released including histamine, which induces sneezing via the trigeminal nerve resulting in rhinorrhoea by stimulating mucus glands (Akhouri and House, 2023). Nasal congestion in AR is caused by leukotrienes and prostaglandins which act on the blood vessels. Four to six hours after the initial response, an arrival of cytokines, such as interleukins (IL)-4 and IL-13, from mast cells occurs which signifies the late-phase response of AR (Pawankar et al, 2011). This process facilitates the infiltration of eosinophils, T-lymphocytes, and basophils into the nasal mucosa and produces nasal oedema, resulting in congestion (Fig 1) (Pawankar et al, 2011).
Classification
The classification of allergic rhinitis from ARIA guideline (Klimek et al, 2019) is based on the level of severity (mild or moderate-severe) and frequency of symptom occurrence (intermittent or persistent). Classification of AR can be helpful when deciding the most appropriate treatment for individuals.
Diagnosis – history taking
Allergic rhinitis is a common disorder that is strongly linked to asthma and conjunctivitis. It is usually a long-standing condition that often goes undetected in the primary-care setting (Akhouri and House 2023).
A thorough, allergic history is the best tool for the diagnosis of allergic rhinitis. It should include assessment of the following: a determination of pattern, chronicity, seasonality and triggers of nasal and related symptoms; family history; current medications and response to previous treatments; presence of coexisting conditions; occupational exposure and a detailed environmental history (Settipane 2013).
It is important to consider the impact the symptoms may have on a patient's quality of life, including symptoms of fatigue, breathlessness and sleep disturbance which can result in a lack of concentration, having a negative impact on patients work and or school and learning (Wallace 2008).
Undertaking a history of the nose should include questions aiming to establish whether any of its functions – smelling, conditioning, warming, humidifying inhaled air and voice resonance – is impaired or not. Change of airway resistance and sense of smell are key indicators of nasal pathology. Common presentations seen in primary care are rhinorrhoea, epistaxis, facial pain or sense of pressure and a nasal voice.
Determining if there are any potential red flags at consultation is important, with early onward referral to ENT if the patient has previous blood stained nasal discharge, pain, nasal deformity or unilateral symptoms – consider a two-week, urgent ENT referral (Hayois 2023). Other considerations for urgent referral include excessive bleeding, unusual lumps or nodules, nasal crusting (topical steroid rarely causes crusting) as all requires further investigation. Nasal obstruction – partial or complete - require further investigation into possible polyps, septal deviation, foreign bodies or tumours (NICE 2018).
Assessment
In patients with perennial rhinitis a nasal examination is paramount to differentiate between chronic rhinitis and chronic rhinosinusitis (CRS). Subjects with smell impairment should also be given o a nasal examination. Smell and taste disorders are more frequent in patients with chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP), but they can also be present in individuals with chronic rhinitis and CRS without nasal polyps (Fokkens 2020).
Physical examination of the nasal passages via a flexible nasendoscopy procedure is an exceptionally common procedure in an ENT clinic, however this is considered an extension of routine physical examination (Keane 2020). With lengthy ENT waiting times to review, visual inspection such as looking for signs of rhinorrhoea or patient mouth-breathing can also be useful for assessing severity of symptom impact.
Recording patients baseline symptoms in the absence of objective measurement can be useful to assess severity and help plan, manage and evaluate treatments. The Total nasal symptoms score (TNSS) is a brief questionnaire which evaluates the severity of main symptoms of allergic rhinitis and is widely used in different countries (Tamasauskiene 2021).
Fractionated exhaled nitric oxide (FeNo) measurements in patients with a history of asthma can be a useful tool to help monitor treatment response. FeNO is a marker of lower eosinophilic inflammation in allergic diseases, especially in asthma. FeNO measurement is used for asthma diagnosis, to differentiate its phenotype and to monitor treatment response (Verini 2010). In patients with allergic rhinitis, measurement of FeNO might also indicate the presence of eosinophilic inflammation and might predict the development of lower airway symptoms (Cirillo 2009).
Treatment
Antihistamines, intranasal corticosteroids, decongestants, intranasal anticholinergics, intranasal cromolyn, leukotriene receptor antagonists and immunotherapy have been used in the treatment of AR (Rahim, 2021). Because the underlying mechanisms of AR are complex, the development of single-drug treatment might not be enough to treat a wide spectrum of the disease (Jantrapirom et al, 2021). Although the standard guidelines classify and provide suitable diagnosis and treatment, a high proportion of people with AR are still without any means of controlling it (Jantrapirom et al, 2021). Moreover, the benefits of AR drugs are sometimes accompanied by undesirable side effects. Therefore, an approach which includes allergen avoidance, pharmacotherapy and patient education is recommended (Scadding et al, 2017).
Initial treatment for AR is allergen avoidance, wherever practical. Providing education and advise on common seasonal and perennial allergens, alongside trigger avoidance, is important to reduce symptom burden. Additional advise on saline irrigation of the nasal passages, using a nasal wash, may be adequate to manage symptoms before adding in medications.
In mild allergic rhinitis, oral non-sedating antihistamines should be considered as first line treatment. In case of moderate or severe symptoms, or where treatment with antihistamines has failed, then topical nasal corticosteroid spray (NCS) is recommended (BSACI 2017). NCS can be used for both seasonal and perennial disease and is advisable to start preventatively two-weeks before the season starts, to enable efficacy. (BSACI 2017).
The treatment steps to which can be taken are summarised in fig 3.
Education is an essential component of AR management to improve concordance and treatment outcomes. It is necessary to prescribe using a shared decision-making approach, discussing the purpose of the medication, mode of action and possible side effects (RPS, 2022) as well as counselling the patient on correct nasal spray technique (Scadding, 2017).
Conclusion
AR is a common, atopic, (Ig)E-mediated disease, presenting with symptoms of sneezing, nasal congestion, clear rhinorrhoea, and nasal pruritus which adversely impacts on patients' quality of life (Akhouri and House, 2023).
The classification of allergic rhinitis, mild or moderate-severe and intermittent or persistent can be helpful when deciding the most appropriate treatment for individuals Klimek et al, 2019.
The diagnosis of AR is made using a thorough patient history, examination of the nasal passages and objective testing such as questionnaires and FeNO. Management of AR uses a combination of allergen avoidance, non-medication strategies such as nasal rinsing and pharmacotherapy, all supported with patient education (Scadding et al, 2017, Jantrapirom et al, 2021, BSACI 2017).
