Pharmacotherapy for AR in South Africa
Allergic rhinitis is very widespread in South Africa. The South African Allergic Rhinitis Working Group (SAARWG) recently released comprehensive management guidelines for the condition. Combination therapies, usually consisting of corticosteroids and an antihistamine, are also available locally.
Allergic rhinitis (AR) is a widespread chronic condition estimated to impact 10% to 40% of the global population. It significantly impairs quality of life (QoL) by reducing productivity and causing complications such as asthma, rhinosinusitis, otitis media, and poor sleep quality. AR can also exacerbate mood disorders and cognitive issues, particularly in children, who may face chronic fatigue and learning difficulties.
AR is a Type 1 hypersensitivity reaction where allergens bind to allergen-specific IgE on mast cells in the nasal mucosa. This triggers the release of histamine and other mediators, leading to early-phase symptoms such as itching, sneezing, and rhinorrhea. The late-phase response involves persistent nasal inflammation and immune cell infiltration, which can cause chronic symptoms and increased nasal responsiveness to allergens.
AR and asthma frequently occur together and nearly 80% of people with asthma also have AR. This is often expressed as the theory of “united airway diseases”, in terms of which AR and asthma are subtypes of the same condition. Effective management of AR can improve asthma control, enhance QoL, and reduce healthcare costs by minimising asthma-related hospitalisations.
Globally, AR is recognised as a significant public health issue by organisations like the World Allergy Organisation. However, management guidelines are often designed for high-income countries. In South Africa (SA), managing AR faces unique challenges due to economic constraints, logistical issues, and health literacy barriers. These factors can lead to underdiagnosis and suboptimal treatment.
PHARMACOTHERAPY
- Intranasal corticosteroids (INCS)
INCS are the first-line treatment for AR due to their broad efficacy in managing various symptoms. They are recommended for continuous use in perennial AR and intermittent use for seasonal AR. Their onset of action is typically within 7 to 12 hours, with peak efficacy after 2 weeks of regular use. Newer INCS like fluticasone propionate, fluticasone furoate, and mometasone furoate offer better glucocorticoid receptor selectivity and minimal systemic bioavailability. Despite this, they can cause local side effects such as nasal dryness and epistaxis. Long-term use of INCS drops and depot intramuscular steroid injections is discouraged due to potential systemic risks.
- Systemic antihistamines (AH)
H1-Antihistamines are effective for itching, sneezing, and rhinorrhea but less so for nasal congestion. Second- and third-generation AH, such as desloratadine and levocetirizine, are preferred over first-generation AH due to fewer sedative effects. The South African Allergic Rhinitis Working Group (SAARWG) recommends newer generation AH and alternative options if side effects occur.
- Intranasal antihistamines (INAH)
INAH like olopatadine and azelastine offer rapid relief (within 15 minutes) and are particularly effective for AR symptoms in children. However, their high cost and limited availability in South Africa pose challenges. The combination intranasal spray mometasone/olopatadine, approved for use in South Africa, offers a promising solution.
- Topical nasal decongestants
Decongestants such as phenylephrine and oxymetazoline provide short-term relief by causing vasoconstriction in the nasal mucosa but can lead to rebound congestion if used beyond 5 to 10 consecutive days. They should be used cautiously, preferably alongside INCS.
- Leukotriene receptor antagonists (LTRAs)
LTRAs, effective for nighttime symptoms, are less effective than INCS for overall symptom control and QoL. They are not recommended as first-line treatments unless accompanied by conditions like asthma.
- Allergen immunotherapy (AIT)
AIT, including sublingual (SLIT) and subcutaneous (SCIT) options, is the only disease-modifying treatment for AR. It aims to desensitize individuals to allergens, reducing symptom severity, medication needs, and the progression from AR to asthma. Treatment generally lasts at least 3 years and may be extended based on individual response.
- Advanced treatments
For severe cases, consider immunotherapy, omalizumab, or surgery. Immunotherapy should be considered after optimizing pharmacotherapy and allergen avoidance.
COMBINATION THERAPY
The current recommendation for moderate to severe AR includes combination intranasal therapy, which combines an INCS with an intranasal antihistamine. This approach addresses multiple pathways of allergic inflammation and symptoms: corticosteroids target inflammation and blockage, while antihistamines alleviate itchiness, runniness, and sneezing.
THE ADHERENCE ISSUE
Adherence to nasal sprays can be challenging due to forgetfulness or preference for oral antihistamines. Immediate symptom relief from combination therapy can address these issues, providing quicker feedback on efficacy and encouraging consistent use. The 2016 ARIA guidelines advocate for combination therapies as initial treatment for moderate to severe AR, now extended to younger patients due to both scientific and psychological reasons. Proper use of nasal sprays involves aiming the spray towards the back and sides of the nasal cavity, avoiding the nasal septum to prevent irritation and epistaxis.
CONCLUSION
Effective management of allergic rhinitis involves a multifaceted approach: accurate diagnosis, appropriate classification, and tailored treatment plans. Intranasal combination therapies offer immediate and long-term benefits, enhancing patient adherence and improving treatment outcomes. Proper medication use, patient education, and lifestyle adjustments are essential for managing AR effectively. In South Africa, addressing the unique challenges of AR management requires a comprehensive understanding of local constraints and the adoption of evidence-based treatment strategies.
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REFERENCES
Levin, M, 2024. What’s new in AR management? [Webinar video] 6 June 2024. Available at: https://event.webinarjam.com/go/replay/765/2or8obmrqclr0agxmfk
Richards, G, et al, 2024. Allergic rhinitis: Review of the diagnosis and management: South African Allergic Rhinitis Working Group. South African Family Practice. (Online) 2078-6204.
NHS UK Website. (2024, February 19). About betamethasone tablets. Nhs.uk. Available at: www.nhs.uk/medicines/betamethasone-tablets/about-betamethasone-tablets
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