Epidemiology

The prevalence of allergic rhinitis varies widely, but good epidemiologic studies report that 20 to 30% of adults and up to 40% of children live with the condition. It is characterised by the morbidity of the nasal symptoms, impairment of quality of life and numerous comorbidities (1).

A telephone survey of 2765 people with a diagnosis of nasal or ocular allergies or both assessed seasonality and symptoms of allergic rhinitis (2).

• 78% reported seasonal symptoms, with the peak during the tree season (March to May) and a lesser peak in the fall weed season (September).
• Nasal congestion was the symptom most commonly rated as "extremely bothersome" (39% of respondents), followed by red, itchy eyes (34%).

A 2017 study of people with allergic rhinitis determined that it interferes with sleep, which leads to daytime sleepiness and impaired quality of life (3).

• 66% of adults and 43% of children with moderate to severe allergic rhinitis reported sleep disturbances
• Compared to those with mild allergic rhinitis, those with moderate to severe allergic rhinitis reported more fatigue, anxiety, depression, difficulty with socialising and perceived signs of cognitive dysfunction

Another study investigated patient experiences with allergen immunotherapy (4).

• Not surprisingly, the most common reason for allergen immunotherapy was failure of other medications to resolve symptoms.
• More than one-half of the respondents had never heard of allergen immunotherapy. Respondents’ understanding of allergen immunotherapy indicated a need for educational efforts.
• One-fifth of respondents had been treated with allergen immunotherapy.
• The primary benefit of subcutaneous immunotherapy was effective symptom relief, and convenience was cited most often as a benefit of sublingual immunotherapy.

A study in 2020 identified numerous risk factors associated with allergic rhinitis (5).

• Male gender, family history of atopy.
• Frequent upper respiratory infections, history of tonsillectomy.
• Smoking at home, birds at home, visible mould in the bedroom.
• Living in a weedy area, living in the vicinity of an air-polluting factory, heavy-vehicle traffic.
• The study also found asthma to be the most significant comorbidity.

The economic burden of allergic rhinitis is estimated to be between 2 and 5 billion dollars in direct health expenditures annually in the United States. An additional 2 to 4 billion dollars is lost in employee productivity annually. Both absenteeism and presenteeism (present at work but at a diminished level of functioning) are contributing factors (6).

The impact of climate change on allergic rhinitis is becoming a subject of active research (7).

• Primary estimates are that sensitisation to ragweed will increase in Europe from 33 to 77 million people by 2041–2060.
• It is also predicted that ragweed pollen allergy will extend into regions where it is currently uncommon (Germany, Poland, France).
• As pollen concentrations rise and the pollen season becomes longer, there may be an increase in the severity of symptoms.

References:

1. Meltzer EO. Allergic rhinitis: burden of illness, quality of life, comorbidities, and control. Immunol Allergy Clin North Am. 2016;36(2):235–48.
2. Bielory L, Skoner DP, Blaiss MS, et al. Ocular and nasal allergy symptom burden in America: the Allergies, Immunotherapy, and RhinoconjunctivitiS (AIRS) surveys. Allergy Asthma Proc. 2014;35(3):211–8.
3. Dass K, Petrusan AJ, Beaumont J, et al. Assessment of sleep disturbance in children with allergic rhinitis. Ann Allergy Asthma Immunol. 2017;118(4):505–6.
4. Skoner DP, Blaiss MS, Dykewicz MS, et al. The Allergies, Immunotherapy, and RhinoconjunctivitiS (AIRS) survey: patients’ experience with allergen immunotherapy. Allergy Asthma Proc. 2014;35(3):219–26.
5. Sultész M, Horváth A, Molnár D, et al. Prevalence of allergic rhinitis, related comorbidities and risk factors in schoolchildren. Allergy Asthma Clin Immunol. 2020;16(1):98.
6. Seidman MD, Gurgel RK, Lin SY, et al. Clinical practice guideline: allergic rhinitis. Otolaryngol Head Neck Surg 2015;152(1Suppl):S1–43.
7. Lake IR, Jones NR, Agnew M, et al. Climate change and future pollen allergy in Europe. Environ Health Perspect. 2017;125(3):385–91.