Allergy and sinus medication encompasses a broad range of treatments used to manage some of the most common conditions seen in UK clinical practice. Allergic rhinitis affects around one in five people in the UK, while sinusitis — often a complication of allergies or viral infections — causes significant discomfort and lost productivity each year. From over-the-counter antihistamines and intranasal corticosteroids to prescription-only options and saline irrigation, understanding which treatment is appropriate, how to use it correctly, and when to seek professional advice is essential for safe and effective self-management. This guide covers the key options available in the UK, aligned with NHS and NICE guidance.
Summary: Allergy and sinus medication in the UK includes non-sedating antihistamines, intranasal corticosteroids, decongestants, and saline irrigation, selected according to symptom type and severity in line with NICE guidance.
- Intranasal corticosteroids (e.g. fluticasone, mometasone) are the most effective treatment for moderate-to-severe allergic rhinitis and nasal blockage, per NICE recommendations.
- Second-generation antihistamines (cetirizine, loratadine, fexofenadine) are preferred over sedating first-generation options such as chlorphenamine for daytime allergy symptom control.
- Topical nasal decongestants should not be used for more than five to seven consecutive days due to the risk of rebound congestion (rhinitis medicamentosa).
- Montelukast carries an MHRA safety warning for neuropsychiatric reactions including mood changes, sleep disturbances, and — rarely — suicidal ideation; patients must be counselled before starting.
- NICE advises against routine antibiotics for acute sinusitis, as most cases are viral and resolve within two to three weeks with supportive care.
- Seek emergency care (999 or A&E) if sinus symptoms are accompanied by eye swelling, visual changes, sudden severe headache, confusion, or neck stiffness.
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Understanding Allergies and Sinus Conditions in the UK
Allergic rhinitis affects around one in five people in the UK, while chronic rhinosinusitis is defined by symptoms persisting 12 weeks or longer; the two conditions frequently overlap but have distinct clinical features and management pathways.
Allergic conditions and sinus problems are among the most common reasons people seek medical advice in the UK. Allergic rhinitis — often called hay fever — affects approximately one in five people in the UK at some point in their lives, according to NHS estimates. It occurs when the immune system overreacts to airborne allergens such as pollen, dust mites, pet dander, or mould spores, triggering an inflammatory response in the nasal passages and airways.
Sinusitis (more precisely termed rhinosinusitis) involves inflammation of the sinuses — the air-filled cavities around the nose and eyes. It may develop as a complication of a cold or allergic rhinitis, or arise independently. Acute sinusitis typically resolves within a few weeks. Chronic rhinosinusitis is generally defined as the presence of two or more symptoms — including nasal obstruction or nasal discharge, and often facial pain/pressure or reduced sense of smell — persisting for 12 weeks or longer, supported by clinical examination or investigation. Chronic rhinosinusitis may occur with or without nasal polyps, and each subtype has distinct management implications.
The overlap between allergic rhinitis and sinusitis is clinically significant. Persistent nasal inflammation from allergies can impair sinus drainage, creating conditions that favour infection or chronic irritation. However, it is important to distinguish between the two, as their symptoms differ in important ways:
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Sneezing, nasal itch, and itchy or watery eyes are characteristic of allergic rhinitis rather than sinusitis
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Facial pain or pressure, purulent (discoloured) nasal discharge, and reduced or lost sense of smell point more towards rhinosinusitis
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Nasal congestion and blockage and runny nose (rhinorrhoea) are common to both conditions
Non-allergic rhinitis (for example, vasomotor or irritant rhinitis) can produce similar nasal symptoms without an allergic trigger, and may require a different management approach. A GP can help distinguish between allergic and non-allergic causes and guide patients towards the most effective treatment pathway.
When to seek urgent help: Seek emergency care (call 999 or go to A&E) if sinus symptoms are accompanied by swelling around the eyes, visual changes, severe unilateral headache, confusion, or neck stiffness, as these may indicate rare but serious complications such as orbital or intracranial involvement.
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| Medication Type | Examples (UK) | Main Use | OTC / POM | Key Side Effects | Important Warnings |
|---|---|---|---|---|---|
| Second-generation antihistamines | Cetirizine, loratadine, fexofenadine | Sneezing, nasal itch, watery eyes in allergic rhinitis | Mostly OTC; fexofenadine 180 mg is POM — check with pharmacist | Headache, mild GI upset; minimal sedation | Avoid alcohol; check drowsiness warnings before driving |
| First-generation antihistamines | Chlorphenamine | Allergic rhinitis; short-term symptom relief | OTC | Significant sedation, dry mouth, urinary retention, blurred vision | Do not drive or operate machinery; not preferred for routine use |
| Intranasal corticosteroids | Beclometasone, fluticasone, mometasone | Moderate-to-severe allergic rhinitis; nasal blockage; rhinosinusitis | OTC and POM | Nasal dryness, mild irritation, occasional nosebleeds | Use correct technique; monitor growth in children; caution with CYP3A4 inhibitors (e.g., ritonavir) |
| Topical nasal decongestants | Xylometazoline nasal spray | Short-term nasal congestion relief | OTC | Rebound congestion (rhinitis medicamentosa) if overused | Do not use for more than 5–7 consecutive days |
| Oral decongestants | Pseudoephedrine | Nasal congestion | Pharmacy-only (P); subject to restrictions | Raised blood pressure, palpitations, insomnia, anxiety | Avoid in hypertension, cardiovascular disease, hyperthyroidism, or with MAOIs; rare risk of PRES/RCVS (MHRA 2024) |
| Leukotriene receptor antagonists | Montelukast | Allergic rhinitis with coexistent asthma; second-line use | POM | Sleep disturbances, mood changes, anxiety | MHRA warning: risk of neuropsychiatric reactions including depression and suicidal ideation; counsel patients before starting |
| Saline nasal irrigation | Isotonic or hypertonic saline rinses | Adjunct for allergic rhinitis and sinusitis; clears mucus and allergens | OTC | Generally none; well tolerated | Suitable for adults and children; use alongside other treatments |
Types of Medication Used to Treat Allergy and Sinus Symptoms
Intranasal corticosteroids are first-line for moderate-to-severe allergic rhinitis and nasal blockage, while non-sedating antihistamines are preferred for sneezing and itch; decongestants, saline irrigation, and leukotriene antagonists serve as adjuncts or alternatives.
A range of allergy and sinus medications is available in the UK, spanning over-the-counter (OTC) products and prescription-only medicines (POMs). The choice of treatment depends on the nature, severity, predominant symptoms, and duration of the condition, in line with NICE and BSACI guidance.
Antihistamines are effective for allergic rhinitis, particularly where sneezing, nasal itch, and eye symptoms predominate. Second-generation, non-sedating antihistamines — such as cetirizine, loratadine, and fexofenadine — are preferred over older first-generation options such as chlorphenamine, which cause significantly more sedation. Most second-generation antihistamines are available without prescription from pharmacies; however, some strengths remain prescription-only (for example, fexofenadine 180 mg is a POM in the UK — check with your pharmacist). For nasal blockage or persistent or moderate-to-severe symptoms, antihistamines alone are often insufficient.
Intranasal corticosteroids (e.g., beclometasone, fluticasone, mometasone) are considered the most effective treatment for moderate-to-severe allergic rhinitis and for nasal blockage, as recommended by NICE. They reduce nasal inflammation directly at the site of action and are available both OTC and on prescription. Regular, consistent use is essential — benefits may take several days to become fully apparent. If a single treatment is insufficient, combining an intranasal corticosteroid with a non-sedating antihistamine is a recognised, evidence-supported strategy.
Intranasal antihistamines (e.g., azelastine nasal spray) and combination intranasal sprays containing both azelastine and fluticasone are available on prescription and may be considered where standard treatments have not provided adequate relief.
Decongestants, such as xylometazoline nasal sprays, relieve nasal congestion by constricting blood vessels in the nasal mucosa. Topical nasal decongestants should not be used for more than five to seven consecutive days due to the risk of rebound congestion (rhinitis medicamentosa). Oral decongestants containing pseudoephedrine are subject to pharmacy restrictions in the UK; they are not suitable for young children, and age restrictions apply — always check the patient information leaflet (PIL) or ask your pharmacist.
Saline nasal irrigation is a simple, well-tolerated adjunct that helps clear mucus and allergens from the nasal passages. It is suitable for both adults and children and is often recommended alongside other treatments for both allergic rhinitis and sinusitis.
For more severe or persistent allergic disease, a GP may consider leukotriene receptor antagonists such as montelukast — particularly in patients with coexistent asthma or those who cannot tolerate standard therapies. Montelukast is not a routine first-line treatment for allergic rhinitis. The MHRA has issued an important safety warning: montelukast is associated with a risk of neuropsychiatric reactions, including sleep disturbances, mood changes, depression, and suicidal thoughts. Patients and carers should be counselled about these risks before starting treatment, and any concerning changes in mood or behaviour should be reported to a GP promptly.
For appropriate patients, a GP or specialist may refer for allergen immunotherapy, which aims to desensitise the immune system over time and can provide longer-term benefit.
How to Use These Medicines Safely and Effectively
Correct technique for intranasal corticosteroid sprays — including directing the nozzle away from the septum and using consistently every day — is essential for efficacy; oral pseudoephedrine carries serious contraindications and a 2024 MHRA warning regarding rare cerebrovascular events.
Using allergy and sinus medication correctly is essential to achieving the best outcomes and minimising the risk of side effects or treatment failure. Many patients do not experience the full benefit of their medication simply because it is not being used as directed.
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For intranasal corticosteroid sprays, correct technique is critical. Patients should:
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Prime the device before first use by actuating it into the air until a fine mist appears, as directed in the PIL
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Blow the nose gently before use to clear the nasal passages
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Tilt the head slightly forward rather than tilting it back
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Direct the nozzle towards the outer wall of the nostril, away from the nasal septum, to reduce the risk of nosebleeds
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Sniff gently after actuation to draw the spray into the nasal passages, but avoid forceful sniffing or blowing the nose immediately afterwards
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Use consistently every day during the allergy season, even when symptoms feel mild
Patients taking intranasal fluticasone or mometasone who are also prescribed potent CYP3A4 inhibitors (such as ritonavir or cobicistat, used in HIV treatment) should seek pharmacist or GP advice, as these combinations can increase systemic steroid exposure.
For antihistamines, non-sedating options are generally preferred for daytime use. If symptoms are predominantly nocturnal, a once-daily evening dose may be sufficient. Patients should check the label for drowsiness warnings and avoid alcohol or other sedating medicines if affected. First-generation antihistamines such as chlorphenamine can significantly impair driving ability and should not be taken before operating machinery or driving.
Oral decongestants containing pseudoephedrine should be avoided in patients with hypertension (particularly severe or uncontrolled hypertension), cardiovascular disease, hyperthyroidism, severe kidney disease, or those taking monoamine oxidase inhibitors (MAOIs), as serious interactions and adverse effects can occur. Recent MHRA and EMA safety communications (2024) have highlighted a rare but serious risk of posterior reversible encephalopathy syndrome (PRES) and reversible cerebral vasoconstriction syndrome (RCVS) associated with pseudoephedrine. Patients should stop taking pseudoephedrine and seek urgent medical attention if they experience a sudden severe headache, vomiting, confusion, or visual disturbances.
Pregnant or breastfeeding women should always consult a pharmacist or GP before starting any allergy and sinus medication, as safety profiles vary. Similarly, parents should seek professional advice before administering these medicines to young children, as age restrictions apply to many products. Reading the PIL carefully and seeking clarification from a healthcare professional when in doubt remains the safest approach.
Possible Side Effects and What to Watch For
Intranasal corticosteroids are generally well tolerated, but decongestants carry cardiovascular risks and montelukast is associated with neuropsychiatric reactions; call 999 immediately for eye swelling, sudden severe headache, or signs of serious allergic reaction.
Like all medicines, allergy and sinus medications carry the potential for side effects, though many people tolerate them well when used appropriately. Being aware of what to expect — and when to seek further advice — is an important part of safe self-management.
Antihistamines may cause:
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Drowsiness (more common with first-generation types such as chlorphenamine)
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Dry mouth, blurred vision, or urinary retention (anticholinergic effects, particularly with older antihistamines)
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Headache or gastrointestinal upset with second-generation options
Intranasal corticosteroids are generally well tolerated. The most commonly reported side effects include nasal dryness, mild irritation, and occasional nosebleeds. These can often be minimised by using correct technique (see above). Systemic absorption is low at recommended doses; however, prolonged high-dose use — particularly in children — should be monitored by a healthcare professional, as there is a potential for effects on growth and adrenal function. Recurrent nosebleeds or persistent hoarseness should prompt a technique review or discussion with a pharmacist or GP.
Decongestants carry a more notable side-effect profile, including raised blood pressure, palpitations, insomnia, and anxiety. Rebound congestion following prolonged use of topical nasal decongestants is a well-recognised problem that can be difficult to resolve without gradual withdrawal. Rare but serious cardiovascular and cerebrovascular events have been reported with oral pseudoephedrine (see above).
Montelukast has been associated with neuropsychiatric reactions including sleep disturbances, nightmares, anxiety, depression, and — rarely — suicidal ideation. Any such symptoms should be reported to a GP without delay.
These medicines are generally safe when used as directed, but some carry important warnings and rare serious adverse effects. Always read the PIL and seek advice from a pharmacist or GP if you have any concerns.
Patients should seek same-day GP or NHS 111 advice if they experience:
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High fever alongside sinus symptoms, or symptoms that worsen after initial improvement
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Severe facial pain that is not responding to OTC analgesia
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Symptoms that persist beyond 10–12 weeks despite treatment
Patients should call 999 or go to A&E immediately if they experience:
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Swelling around the eyes, visual disturbances, or double vision
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Sudden severe headache, vomiting, confusion, or altered consciousness
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Signs of a serious allergic reaction to the medication itself, such as rash, swelling of the face or throat, or difficulty breathing or swallowing
Suspected side effects from any medicine can be reported to the MHRA via the Yellow Card Scheme at yellowcard.mhra.gov.uk or through the Yellow Card app. This helps the MHRA monitor the safety of medicines used in the UK.
NHS Guidelines and Accessing Treatment in the UK
NICE recommends a stepwise approach starting with pharmacy-led OTC treatment; antibiotics are not routinely prescribed for acute sinusitis, and referral to ENT or an allergist is indicated for chronic or complex cases not responding to 8–12 weeks of intranasal corticosteroids.
In the UK, the management of allergic rhinitis and sinusitis is guided by NICE clinical guidelines (including NICE CKS: Allergic rhinitis, NICE CKS: Sinusitis, and NICE NG79 on antimicrobial prescribing for acute sinusitis) and NHS recommendations, which emphasise a stepwise approach — starting with the least invasive, most cost-effective treatments before escalating to specialist care where necessary.
For mild-to-moderate allergic rhinitis, NICE recommends selecting treatment based on predominant symptoms and severity. A non-sedating antihistamine is appropriate where sneezing, itch, and eye symptoms predominate; an intranasal corticosteroid is preferred where nasal blockage is the main concern or symptoms are persistent or moderate-to-severe. If one treatment is insufficient, combining both is a recognised and evidence-supported strategy.
Acute sinusitis is predominantly viral in origin, and NICE NG79 advises against the routine prescribing of antibiotics. Most cases resolve within two to three weeks with supportive measures, including adequate hydration, saline nasal irrigation, and OTC analgesia such as paracetamol or ibuprofen. Steam inhalation is not recommended by NICE due to limited evidence of benefit and the risk of scalding. Antibiotics may be considered if symptoms are severe, if there is no improvement after 10 days, or if symptoms worsen after initial improvement (a pattern sometimes called "double-worsening"). In some cases, a back-up antibiotic prescription may be appropriate, to be used only if symptoms do not improve as expected.
Accessing treatment in the UK is straightforward for most patients:
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Community pharmacies are the first port of call for mild symptoms; pharmacists can recommend appropriate OTC allergy and sinus medication, advise on correct use, and identify when further assessment is needed
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NHS 111 can provide urgent advice outside of GP hours or when symptoms are worsening
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GP consultation is recommended for persistent, severe, or recurrent symptoms, or where OTC treatments have failed
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Referral to an ENT specialist or allergist may be arranged for complex cases, including chronic rhinosinusitis not responding to 8–12 weeks of intranasal corticosteroids with or without saline irrigation, recurrent acute sinusitis, unilateral symptoms, nasal polyps, unexplained epistaxis, or where allergen immunotherapy is being considered
The NHS also offers allergy testing through specialist services for patients with unclear triggers or severe disease. Patients are encouraged to keep a symptom diary to help identify patterns and triggers, which can significantly improve the effectiveness of any allergy and sinus medication regimen.
Frequently Asked Questions
What is the most effective allergy and sinus medication available in the UK?
Intranasal corticosteroids such as fluticasone or mometasone are considered the most effective treatment for moderate-to-severe allergic rhinitis and nasal blockage, as recommended by NICE. For sneezing and itch, a non-sedating antihistamine such as cetirizine or loratadine is appropriate, and combining both is a recognised strategy when one treatment alone is insufficient.
Do I need antibiotics for sinusitis in the UK?
No — NICE guidance advises against routine antibiotic prescribing for acute sinusitis, as most cases are caused by viruses and resolve within two to three weeks with supportive measures such as saline nasal irrigation and OTC analgesia. Antibiotics may be considered if symptoms are severe, worsen after initial improvement, or fail to resolve after 10 days.
Are nasal decongestant sprays safe to use long term for sinus congestion?
No — topical nasal decongestants such as xylometazoline should not be used for more than five to seven consecutive days, as prolonged use causes rebound congestion known as rhinitis medicamentosa, which can be difficult to resolve. For longer-term nasal congestion, an intranasal corticosteroid is a safer and more effective option.
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