Histamine induces sneezing via the trigeminal nerve and plays a role in rhinorrhoea by stimulating mucous glands. Other immune mediators, such as leukotrienes and prostaglandins, are also implicated as they act on blood vessels to cause nasal congestion.
Four to six hours after the initial response, an influx of cytokines, such as interleukins (IL)-4 and IL-13, from mast cells occurs, signifying the development of the late-phase response. These cytokines then facilitate the infiltration of eosinophils, T-lymphocytes, and basophils into the nasal mucosa and produce nasal oedema, resulting in congestion.
Non-IgE-mediated hyperresponsiveness can develop due to eosinophilic infiltration and nasal mucosal obliteration. The nasal mucosa becomes hyperreactive to normal stimuli (such as tobacco smoke and cold air) and causes symptoms of sneezing, rhinorrhoea, and nasal pruritis.
Epidemiology
The prevalence of AR based on physician diagnosis is about 15%. However, the prevalence is estimated to be as high as 30% based on patients with nasal symptoms. AR is known to peak in the second to fourth decades of life and then gradually decline. AR is one of the most common chronic paediatric disorders. According to data from the International Study for Asthma and Allergies in Childhood, 14% in the 13- to 14-year age group and 8% in the six- to seven-year age group display symptoms of rhinoconjunctivitis linked to AR. Seasonal AR seems to be more common in the paediatric age group, whereas chronic rhinitis is more prevalent in adults.
A systematic review from 2018 estimated that 3% of adults had missed work, and 36% had impaired work performance due to AR. Economic evaluations have shown that indirect costs associated with lost work productivity account for most of the cost burden for AR.
Risk factors for developing AR include a family history of atopy, male sex, a presence of allergen specific IgE, and a serum IgE greater than 100 IU/mL before age six. Studies in young children have shown a higher risk of AR in those with an early introduction to foods or formula and/or heavy exposure to cigarette smoking in the first year of life.
According to Akhouri et al (2023), although many recent studies have evaluated the link between pollution and the development of AR, no significant correlation yet exists. Interestingly, there are several factors identified that may have a protective effect on the development of AR. The role of breastfeeding in the development of AR is often debated, but it is still recommended due to its many other known benefits and no associated harms.
There is no evidence that pet avoidance in childhood prevents AR. However, it is hypothesised that early pet exposure may induce immune tolerance. There is a growing interest in the ‘farm effect’ on the development of allergies, and a meta-analysis of eight studies showed a 40% lower risk in subjects who had lived on a farm during their first year of life.
Patient examination
Taking a thorough, detailed history is an essential part of the evaluation of AR, and questions should focus on the types of symptoms, the time, duration, and frequency of symptoms, suspected exposures, exacerbating/alleviating factors, and seasonality. Patients with intermittent or seasonal AR have symptoms of sneezing, rhinorrhoea, and watery eyes, while patients with chronic AR often complain of postnasal drip, chronic nasal congestion, and obstruction.
These patients will often have a family history of AR or a personal history of asthma. Patients with intermittent rhinitis may report triggers such as pollens, animal dander, flooring/upholstery, mould, humidity, perfumes, and/or tobacco smoke.
Patients may display mouth breathing, frequent sniffling and/or throat clearing, transverse supra-tip nasal crease, and dark circles under the eyes (allergic shiners). Nasal supratip crease is more common in children. Anterior rhinoscopy typically reveals swelling of the nasal mucosa and thin, clear secretions. The inferior turbinates may take on a bluish hue, and cobblestoning of the nasal mucosa may be present.
Whenever possible, an internal endoscopic examination of the nasal cavity should be conducted to assess for nasal polyps and structural abnormalities. Pneumatic otoscopy can be used to assess for eustachian tube dysfunction, which can be a common finding in patients with allergic rhinitis. Sinuses may be tender to the touch in patients with chronic symptoms. Check these patients carefully for signs of asthma or dermatitis and question them regarding aspirin sensitivity.
Prognosis
Prevalence of AR seems to peak in adolescence and gradually decreases with age. In a longitudinal study, after 23 years, almost 55% of patients showed symptom improvement, with 41.6% of those being symptom-free. Patients who had an onset of symptoms at a younger age were more likely to show improvement. The severity of AR can vary over time and depends on various factors such as location and season.
Effects on QoL
Quality of life (QoL) is reduced with this condition due to the direct effects of its primary symptoms on the patient’s life. AR also tends to cause sleep disorders, fatigue, impaired memory, and depression, all of which contribute to a reduced QoL. According to the Allergic Rhinitis Impact on Asthma guidelines, the QoL in patients with rhinitis dictates their rhinitis classification. For instance, sleep disorders are only associated with the moderate to severe form of rhinitis and not with its mild form.
The assessment of QoL has become a major area of interest for clinical research. Questionnaires have been developed to assess the effect of clinical management and of reducing the symptoms of chronic diseases on the patients’ daily life. They are also used to determine the effect of particular methods of treatment on controlling the disease. The rhinoconjunctivitis quality of life questionnaire (RQLQ) was prepared by Juniper and Guyatt in 1991 to assess the QoL in patients with rhinoconjunctivitis.
Various studies were performed to assess QoL of AR patients. Shariat et al evaluated the QoL in AR patients. Their study showed that the severity of the disease adversely affects the patients’ QoL. A study conducted in Brazil (2009) showed that AR has adverse effects on psychological and physical health in children.
Clinical findings
Rhinorrhoea was the most prevalent symptom among the participants. Other main symptoms of AR included itchy nose, nasal congestion and watery eyes (82%, 70% and 69%, respectively).
Sinusitis was the most common (29%) concomitant disease of AR asthma (12%). A poor sense of smell (7%) and a poor sense of taste (3%) were other concurrent conditions.
Regarding the RQLQ, among the total of 146 patients, the QoL was mildly affected in 38% and severely influenced in 62% of patients. QoL was reduced significantly in patients with severe intermittent allergic rhinitis (p<0.05). No significant relationships were observed between quality of life and gender (p<0.456). A significant relationship was found between QoL and severity of the disease (p=0.000).
The results of the study showed, in the majority of patients, that their QoL had been affected by problems caused by AR, including general sleep problems, morning symptoms, and practical problems during wake time. In the studies conducted by Shariat et al, Hubert Chen et al, and Monico Mit et al, more than 60% of the patients suffered from sleep problems and problems when awake. The authors found that patient QoL was affected by severe sleep problems (and problems during wake time) in 62% of the patients.
Patients with severe permanent or intermittent disease had a poorer QoL since the severity of the disease and associated symptoms tended to affect the patients’ physical and mental well-being, making their life more difficult. These observations are consistent with those from studies conducted by Shariat et al, which showed that patients with a more severe type of the disease have a poorer QoL.
Complications
Chronic rhinosinusitis can be a complication of AR. It is characterised by nasal inflammation with symptoms of nasal congestion or discharge, lasting for longer than three months. Chronic rhinosinusitis may also show nasal polyps, which form as a result of chronic inflammation of the paranasal sinus mucosa. Nasal polyps are typically benign and present bilaterally.
Unilateral nasal polyps should raise concerns for malignancy. The incidence of nasal polyps in the general population is approximately 4% and is more common in males. Treatment options include topical steroids and saline irrigation. Surgical removal is reserved for patients who do not respond to medical therapy.
Sensitisation to allergens in AR can alter the immunological parameters of the adenoids, resulting in adenoid hypertrophy. Eustachian tube dysfunction commonly manifests in patients with AR and presents as ear fullness, otalgia, and ear-popping. Approximately 10%-40% of patients with AR also have concurrent asthma, and some studies suggest asthma is more common in moderate-to-severe persistent rhinitis.
Many studies have demonstrated AR to be an independent risk factor for asthma, especially in patients diagnosed with AR during infancy. Some other associated complications include otitis media with effusion, persistent cough, and eosinophilic oesophagitis.
Occupational AR and QoL impact
Maoua et al evaluated QoL and work productivity and activity impairment among patients with allergic occupational rhinitis (OR). Patients with allergic OR do not only complain of clinical problems related to their symptomatology, but also of problems related to their occupation, such as inability to continue work, indication of allergen eviction and possible job loss. These professional changes can also interact with QoL. In the literature, several studies have evaluated the QoL in patients with occupational asthma but only few studies explored QoL in patients with OR.
In this study, female workers had more impaired QoL scores. Housekeeping activities may explain a part of these findings. Women are generally cumulating efforts at work and at home and are exposed to household products that can aggravate rhinitis symptoms, impacting QoL. These findings were similar to those reported by Shariat et al conducted in 2011 among 110 patients with non-occupational AR.
Other studies mainly focused on the impact of exposure cessation on QoL. Van Wijk et al concluded that work cessation had beneficial effects on improving the QoL of patients with OR. Power et al found that among their study population of 29 patients allergic to latex, 90% noted that the total suppression of the allergen resulted in disappearance of the effects of nasal and ocular symptoms on their QoL.
Several other studies showed an impairment of work productivity and activity among patients with AR. Studies of Bousquet et al showed an absenteeism ranging from 0 to 4%, a presenteeism ranging from 18%-23%, a work productivity loss from 18%-26% and an overall activity impairment ranging from 20%-27%.
Absenteeism and presenteeism varies from one country to another due to cultural, socioeconomic, and health insurance factors. Compared to other diseases, AR seemed to have more negative impact on work productivity and activity than hypertension and diabetes, and only depression caused more impairment than AR in the study of De la Hoz Caballer.
There are associations between QoL and work productivity among patients with AR. Even if absenteeism rates seem to be moderate, work productivity is clearly reduced because of important presenteeism percentages.
Identification of factors such as age, gender and QoL impairment could help to identify workers with higher risk of productivity and activity impairment. A rigorous application of preventive measures and a medical control of the disease should reduce the burden of allergic occupational rhinitis and improve QoL and work productivity.
Conclusion
AR can adversely affect sleep quality, mood, and daily activities in patients. Given the significant effects of these symptoms on the patients’ QoL, making an early diagnosis of the disease is the first step to overcoming it. The subsequent steps are reducing environmental allergens and taking measures to prevent the incidence of concomitant diseases, such as asthma and sinusitis.
References
- Akhouri S, House SA. Allergic Rhinitis. [Updated 2023 Jul 16]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK538186/#
- Kalmarzi R, Khazaei Z, Shahsavar J, et al. The impact of allergic rhinitis on quality of life: a study in western Iran. Biomed Res Ther, 4(9), 1629-1637, 2017. https://doi.org/10.15419/bmrat.v4i9.370
- Maoua M, Maalel OE, Kacem I, et al. Quality of Life and Work Productivity Impairment of Patients with Allergic Occupational Rhinitis. Tanaffos, 2019.
