Hayfever or seasonal allergic rhinitis is a condition where the nasal mucosa has been sensitised, leading to chronic inflammation and irritation on allergen exposure. The allergens involved are pollens and spores.
It affects around 26 per cent of the population with onset under 30 years old and the UK has the second highest rate in Europe.
Exposure to the allergen causes sensitised mast cells to release histamine and inflammatory mediators. These increase cellular permeability and act on nerve endings and blood vessels.
Within minutes patients experience an acute response and a late response six to 12 hours later. Allergens can affect the nose, throat or eyes (see box for signs and symptoms).
Symptoms tend to occur on a seasonal basis dependent on the presence of airborne allergens. The main allergens are tree pollens, affecting 25 per cent of patients between March and May, and grass pollen, which affects 90 per cent of patients between May and July. 1
Risk factors for hayfever development include history of atopy and a family history of rhinitis. It is also associated with conjunctivitis, sinusitis and nasal polyps.
Perennial rhinitis presents with hayfever symptoms throughout the year. This is more common in adults and can be caused by dust mites. Occupational rhinitis occurs due to allergens at work.
Rhinitis medicamentosa is nasal congestion without sneezing or rhinorrhea caused by overuse of nasal decongestants. Infection usually presents acutely with upper respiratory tract symptoms, fever and green nasal discharge.
Nasal polyps are lesions arising from the nasal mucosa causing symptoms of obstruction and rhinorrhoea. Conditions such as cystic fibrosis and granulomatous disease can also present with nasal symptoms.
Diagnosis is made from a history of symptoms following allergen exposure. Tests are only recommended when the allergen cannot be identified.
Skin prick testing is preferable which assesses IgE bound to cutaneous mast cells. It gives a clear negative or positive response and is repeatable.
If this is unavailable, serum can be sent for allergen-specific IgE antibody test (RAST).2
|Signs and symptoms|
Allergen avoidance is the main method of management.
Patients should be advised to monitor pollen counts, use air conditioning and pollen filters. They should avoid fields and keep all windows shut.
Maintain a stepwise approach to treatment and guide treatment according the patient's quality of life.
Topical nasal antihistamines such as azelastine are better for rhinitis symptoms than oral antihistamines but do not relieve the other symptoms. These should not be used in children under five years.
Topical nasal steroids are more effective than antihistamines and can be used to prevent or control persistent symptoms.
Fluticasone is as effective as beclometasone and has a better safety profile. If they are used to control symptoms start treatment two weeks before allergen exposure is expected.1
Topical nasal decongestants should not be used for more than seven days due to the risk of rhinitis medicamentosa. They can be useful to open up the nose while waiting for other treatments to work.
Intranasal ipratropium should be used if watery rhinorrhoea is the most dominant symptom. Sodium cromogly-cate eye drops can be used for persistent ocular symptoms. A short course of oral steroids can be considered as a last resort.
Review patients two to four weeks after changing treatment to assess symptom control, compliance and technique.
Consider referral to an ENT surgeon if symptoms are unresponsive to treatment. Referral is also advised for patients with unilateral nasal symptoms especially with blood stained discharge or high nasal cavity crusting that could represent a tumour or foreign body. Also, refer if there is nasal perforation, ulceration or collapse.
Complications and prognosis
Hayfever can affect quality of life and in children it can contribute to sleep disturbance and learning difficulties. Chronic swelling of the nasal mucosa can prevent draining of the sinuses predisposing to sinusitis.3
Ten to 20 per cent of patients are cured spontaneously and most improve over time with a 40-65 per cent improvement rate over five to 23 years.3
- Dr Taylor-Walker is a GP locum in Leicestershire
1. Hayfever, Merec Bulletin, www.npc.co.uk/ebt/merec/therap/other/resources/merec_bulletin_vol14_no5.pdf
2. Allergy testing, Lab Test Online www.labtestsonline.org/understanding/analytes/allergy/test.html
3. Allergic rhinitis, Clinical Knowledge Summaries (January 2008), www.cks.nhs.uk/allergic_rhinitis