Hay fever

Contributed by Dr Anthony Crockett, GP and hospital practitioner, Great Western Foundation Hospital, Swindon.

Section 1: Epidemiology and aetiology
Hay fever is a symptom complex caused by allergic inflammation of the nasal mucosa.

The provoking allergens are usually grass, pollen or tree aeroallergens so symptoms characteristically occur at the same time of year in affected patients, corresponding to the relevant seasonal allergen load. Hay fever is more properly termed seasonal allergic rhinitis.

Hay fever affects over three million people in the UK1 and is most prevalent in children and young adults. It is more common in atopic individuals, those with a family history of atopy and hay fever, in first-born children, in higher socio-economic classes and in those with positive allergy skin prick tests.

Hay fever is increasing in prevalence, as are other manifestations of atopy, as predicted by the hygiene hypothesis.

This proposes that relatively sterile childhood environments, including immunisations and antibiotic use, encourage the development of allergic, Th2-driven phenotypes, leading to eczema and food allergies in early infancy and the later development of asthma and hay fever.

Hay fever develops only after several seasons of aeroallergen exposure and rarely appears before three years of age.

Aetiology
The symptoms of hay fever arise from the immediate IgE-mediated mast cell degranulation and release of mediators in response to exposure to aeroallergens to which the individual has previously been sensitised by prior exposure (see figure). These mediators induce sneezing, rhinorrhoea, nasal itch and block.

The late-phase reaction is eosinophil-driven and results in nasal obstruction, nasal hyperreactivity and possible loss of the sense of smell.

There are no long-term structural changes to the nasal tissues as a result of chronic hay fever, even if not treated.

Section 2: Diagnosis
The diagnosis of hay fever is based on the presence of one or more of the following symptoms, which must be present for at least one hour a day for at least two weeks: nasal congestion, rhinorrhoea (anterior and posterior), sneezing and itching.

Hay fever can be classified by severity and chronicity and is usually described by both adjectives, for example 'intermittent, severe' or 'persistent, mild'.2 This classification is useful for choosing management options.

Diagnosis is usually straightforward. A detailed history of the characteristic symptoms of nasal itch and block, sneezing and rhinorrhoea occurring in the spring or summer or at the same time each year in the same individual and which worsen on exposure to specific allergens, is usually sufficient.

Rhinorrhoea is usually clear and bilateral; if purulent, consider infection; if unilateral consider a cerebrospinal fluid leak.

Nasal block is usually due to bilateral anterior nasal tissue oedema and inferior turbinate enlargement.

Examine the nose to exclude a deviated nasal septum, nasal polyps (which are insensitive - test with an orange stick) or septal collapse (consider cocaine abuse).

Crusting can occur in nose-pickers or secondary to nasal steroid use. Some children may develop a transverse nasal crease secondary to wiping their noses with an upward brush of the hand (the atopic salute).

In more severe cases there may be fatigue, headache, sleep disturbance and impaired senses of smell and taste.

There may be other atopic manifestations, especially eczema and asthma. Good control of hay fever may improve asthma control and vice-versa.

There is often an accompanying allergic conjunctivitis with red, itchy, gritty eyes worse on exposure to pollens.

Sticky eyes with profuse mucus or visual problems do not usually occur with uncomplicated allergic conjunctivitis, and should lead to consideration of an alternative diagnosis.

Allergen testing
In most cases of hay fever, the diagnosis and successful management can be made on the basis of a careful history and examination. In more severe or refractory cases, or if considering immunotherapy or allergen avoidance, allergen testing is required.

Skin prick tests are quick and have a specificity and sensitivity of over 70 per cent. They are useful for common aeroallergens and should include house dust mite, cat, dog, pollens, grasses and trees.

Oral antihistamines such as cetirizine should be stopped for five days prior to testing. Total IgE and specific IgE tests are not affected by recent antihistamine ingestion.

Hay fever has a considerable negative effect on the quality of life of patients, including poor school and work performance. These effects are often underrated.3

Section 3: Management
Current management is generally either pharmacological or environmental. Immunotherapy is not common in the UK, but is used more in the rest of Europe and in the US.

Periorbital oedema and allergic conjunctivitis as a result of hay fever

Medication
Oral antihistamines (OAH) are safe, effective, fast-acting and mostly free of side-effects. Second-generation OAH are preferred as they are less sedating, usually last 12-24 hours and their onset of action is not significantly slower than the older first generation OAHs (such as chlorphenamine).

They are effective for relief of most of the symptoms of hay fever. They are best taken regularly, and ideally started before the maximal seasonal exposure to any known provoking allergens. OAH can be combined with any of the nasal therapies.

Inhaled antihistamines (IAH) are as effective as OAH but need to be taken regularly, often up to four times a day; small children do not always tolerate topical therapy.

Intranasal corticosteroids (INCS) are also safe and effective but have a slower onset of action. Again, they are less tolerated by children (and some adults).

Their use can result in nasal crusting or even bleeding; temporarily stopping the therapy allows the nasal mucosa to recover, and directing the spray upwards and outwards minimises these effects.

Anticholinergic intranasal sprays (ACNS) are beneficial when anterior rhinorrhoea is particularly troublesome; ACNS can be combined with INCS or IAH. Nasal decongestants may provide symptomatic relief but should be used only for a few days at a time as their use is associated with rebound mucosal irritability and oedema.

Intranasal cromoglicate is less effective than INCS, but may be a suitable alternative if INCS are not tolerated, or in patients already receiving high-dose topical steroid therapy for their concomitant asthma and eczema.

A short course of oral corticosteroids can provide rapid and effective relief, and is indicated if symptoms are severe or the patient has an imminent important event such as an examination or a wedding; 30-40mg per day for five days for adults, 1-2mg/kg for three to five days for children.

Hay fever with asthma may respond to regular leukotriene receptor antagonists - if there is no improvement after 28 days, do not continue.

Nasal douching with saline is not popular in the UK, but is used elsewhere to good effect and there is good evidence of its efficacy.5 It is safe and inexpensive (see box, below).

Environmental
The aeroallergens that commonly provoke hay fever in the UK are ubiquitous, and complete allergen avoidance is impossible.

Minimising allergen exposure is not easy, and to use this mode of therapy requires dedication and perseverance and is rarely compatible with a normal lifestyle.

Many patients like to feel they are doing everything they can to help themselves, but there is very little evidence to support the efficacy of allergen avoidance.6

Immunotherapy
Allergen immunotherapy should be considered for patients with allergic rhinitis who have demonstrable evidence of specific IgE antibodies to clinically relevant allergens.

Its use depends on the degree to which symptoms can be reduced by avoidance and medication, the amount and type of medication required to control symptoms, and the adverse effects of medications.

Allergen immunotherapy may prevent the development of new allergen sensitisations and reduce the risk for the future development of asthma in patients with allergic rhinitis. Most patients who wish to consider this therapy will need referral to an allergy specialist.

Relative efficacy of drugs used in hay fever (modified BSACI guidelines)4
OAHINCSINAHINAChINCr
Rhinorrhoea***********
Sneezing*******-*
Itch*******-*
Block*****-*
Eye symptoms****--***
Onset time1 hour12 hours15 mins15 mins15 mins
Duration12-24 hours12-48 hours6-12 hours4-12 hours4-6 hours
OAH = oral antihistamines (e.g. loratadine, cetirizine)
INCS = intranasal corticosteroids (e.g. beclometasone, fluticasone, budesonide)
INAH = intranasal antihistamines (e.g. azelastine)
INACh = intranasal anticholinergic agents (e.g. ipratropium)
INCr = intranasal cromogens (e.g. nedocromil, sodium cromoglicate)

Section 4: Prognosis
Most hay fever improves with time, probably due to acquisition of natural immune tolerance.

It is not known whether active medical management affects the natural history of hay fever, although immunotherapy certainly suppresses the symptoms for several years.

The most effective management is pharmacological. INCS and OAH, used separately or together (in more severe cases), will provide effective relief for the majority.

Treatments are more effective if used continuously throughout each patient's known or suspected hay fever season.

Most patients, and especially with more severe hay fever, should start therapy a few weeks before the likely onset of their symptoms and should continue until their season has ended.

New treatments
Sub-lingual immunotherapy has been shown to be effective when used in patients who are allergic to single grass or weed allergens.

A new nasal corticosteroid, fluticasone furoate, is effective for treating nasal and ocular symptoms of hay fever, and is licensed from the age of six years.

The anti-IgE drug omalizumab is currently only licensed for certain types of asthma but may have a role in more severe hay fever. It is expensive and can only be given by injection.

Finally, prospective trials may or may not show that more aggressive and early treatment of hay fever in atopic subjects leads to reduced asthma incidence or severity.

Nasal douching: Advice for patients

  • Take a mug full of tepid, previously boiled water.
  • Add a pinch of salt and a pinch of sodium bicarbonate and mix well.
  • Pour some into the palm of your hand and gently sniff up into your nose.
  • Repeat at least three times on each side.
  • Gargle with the remainder of the solution, allowing the fluid to slip over the soft palate as it is expelled. This will help to help clear the postnasal space.

Source: Royal National Throat, Nose and Ear Hospital

 

Resources

References

1. Allergic rhinitis: common, costly, and neglected. Lancet 2008; 371: 2,057.

2. Bousquet J, van Cauwenberge P, Khaltev N. Workshop Expert Panel. Allergic Rhinitis and its Impact on Asthma (ARIA). in collaboration with the World Health Organization. Executive summary of the Workshop Report. Allergy 2002; 57: 841-55.

3. Blaiss MS. Cognitive, social, and economic costs of allergic rhinitis. Allergy Asthma Proc 2000; 21: 7-13.

4. Scadding G, Durham S, Mirakian R et al. BSACI guidelines for the management of allergic and non-allergic rhinitis. Clin Exp Allergy 2008; 38: 19-42.

5. Taccariello M, Parikh A, Darby Y, Scadding G. Nasal douching as a valuable adjunct in the management of chronic rhinosinusitis. Rhinology 1999; 37(1): 29-32.

6. Sheikh A, Hurwitz B, Shehata YA. House dust mite avoidance measures for perennial allergic rhinitis. Cochrane Database Syst Rev 2007, Issue 1. Art. No.: CD001563.

Further reading

Wallace DV, Dykewicz DB, Bernstein DI et al. The diagnosis and management of rhinitis: An updated practice parameter. J Allergy Clin Immunol 2008; 122(2): S1-S84.

For an archive of all GP clinical reviews visit www.healthcarerepublic.com/clinical/GP.

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