Respiratory allergies: what nurses need to know

Respiratory allergies are among the most prevalent chronic conditions in the UK, affecting an estimated 26% of adults. As demand on specialist allergy services grows, nurses are increasingly well placed to support diagnosis, guide patients through treatment options, and improve medication technique.

Respiratory allergies – known as allergic rhinitis or hay fever – have increased dramatically in the UK since the 1970s. And the UK now ‘has some of the highest prevalence of allergic conditions in the world,’ according to Katherine Knight, an advanced nurse practitioner in allergy at the Allergy Centre of Excellence (ACE),

One-fifth of the UK population is affected by one or more allergic disorders such as food allergy, asthma and eczema, but Ms Knight said that: ‘Respiratory allergies, in particular, have increased 2% every year with an estimated 15% of children and 26% of adults being affected.’

Professor Stephen Durham, a leading allergy specialist at Imperial College London, said: ‘The statistics may have plateaued over the last few years, but certainly between the 1970s and 2000s there was almost a four-fold increase in GP referrals for hay fever.’

The reasons for these increases aren’t entirely clear, but contributing factors may include the introduction of more pollen species such as ragweed; the increased planting of trees like birch and alder, whose pollens are potent allergens; and climate change, which is extending and intensifying pollen seasons.

Additionally: ‘Better recognition of the condition and rates of diagnosis also play a part,’ said Ms Knight, ‘as well as genetics and family history’.

Many experts also suggest the hygiene hypothesis as likely contributing factor. Prof Durham said: ‘The fact that we’re living in increasingly sterile environments means that we’re less exposed to microbes at birth. Consequently, this lack of exposure to microorganisms in early life results in an increased tendency to develop allergic disease.’

Rebecca Seal, food and health journalist and author of Irritated: The Allergy Epidemic and What We Can Do About It, said the problem is also being compounded by air pollution, which lowers the threshold for allergic reactions and can enhance IgE antibody production.

‘If you are exposed to air pollution, your lungs and nasal passages may be more inflamed in general, so anything else which irritates them is going to feel worse. But the other issue is that with pollen in particular, pollution has a couple of effects that intensify things even more.

‘[For example], some polluting particles bind with pollen grains and act like an adjuvant, creating a much bigger inflammatory reaction when the pollen comes into contact with someone who has an allergy.’

Of course, pollen allergies aren’t the only respiratory allergies said to have got worse. Ms Seal said: ‘Dust-mite allergy has become more common over the last 70 years, as our homes have become warmer, damper, and better insulated, with many more soft furnishings – ideal conditions for the mites to live.’

She added: ‘Mould allergies have increased for similar reasons – double glazing keeps homes warmer, but unless really well ventilated, homes also become wetter inside, too, and mould can grow on walls and behind furniture. Many of us don’t have space to dry washing outside, and that contributes to the build-up of moisture too.’

What’s the impact?

The impact of respiratory allergies on a patient’s quality of life, work, and wider health can be significant. Ms Seal said: ‘Calling respiratory allergies “mild” is not very helpful, or accurate.

‘Due to persistent nasal congestion, many people with respiratory allergies experience really poor sleep – particularly people with dust mite allergy, as dust mites live in beds – which can impact work or education, as well as people’s social life.

‘[Meanwhile], seasonal allergies can make it hard to get out into sunshine, to go on holiday or to exercise outdoors, and having pet allergies can make it hard to use public transport and visit houses where animals are allowed inside.’

Ms Knight added that in addition to affecting quality of life, allergic rhinitis elevates health risks as well: ‘It puts people at increased risk of developing asthma, because the upper and lower airways are connected, and those with pre-existing asthma often experience deterioration in asthma symptoms if allergic rhinitis is not well controlled.’

Respiratory allergies have also been shown to cause anxiety and depression, noted Ms Seal. ‘There is even some evidence to show that there is a link between the onset of hay fever in spring and an increased number of suicide attempts.’

Defining and diagnosing respiratory allergies

According to Professor Durham: ‘Allergy is defined first and foremost by symptoms on exposure to the relevant allergen.’ So, if you have a cat allergy, you develop symptoms on cat exposure, if you have a dog allergy, you develop symptoms on dog exposure.

Professor Durham emphasised the importance of examining a patient’s allergy history and the timing of symptoms when seeking to identify a potential allergen. Springtime symptoms are most likely due to tree pollen, summer symptoms to grass pollen, and autumn symptoms to weed pollen.

The most common perennial allergen – all year long rather than seasonal – is house dust mite, and symptoms are often triggered by activities that disturb high concentrations of mite particles, such as making the bed, dusting, or vacuuming.

Additionally, experts underscore the importance of distinguishing between allergies and conditions with similar symptoms like common colds and sinusitis.

Professor Durham said: ‘There’s a very characteristic triad of symptoms that is very specific for allergies — that’s itching or sneezing, watery discharge, and eye symptoms. That triad is almost pathognomonic of allergy. While 100 things can cause a blocked nose, there’s only one thing that causes that triad of itching or sneezing, water discharge, and eye symptoms.’

Once an allergy and potential trigger is identified, the first step is usually to recommend initial treatment options and avoidance measures for removing contact with the suspected allergen where possible. However, it’s important to be aware that not all avoidance measures are practical or reasonable.

Professor Durham said: ‘I’m a bit reluctant to recommend pollen avoidance strategies because it’s the best time of the year for most of us and what they should be doing is treating themselves and enjoying the summer.

‘But you can fit a pollen filter to your car, keep your windows shut, check pollen forecasts, and wash your hair when you come in in the evening because pollen can get stuck in your hair.’

Regarding house dust mite allergy, Ms Knight said: ‘Reducing house dust mite exposure includes regular washing of bed linen at 60°C, airing the bed and room each morning, regular vacuuming of carpeted areas and avoiding clutter in the sleeping area such as soft toys.’

Professor Durham added that avoidance measures for dust mite allergies are expensive, time consuming and may not work. ‘They’re more effective in children than adults. You really need to go the whole nine yards – hard floors, no heavy furnishings, damp dusting, hoovering the bed and mattress once a week, and mite-proof covers on the bed, duvet, and mattress.’

Most importantly, he stated, ‘you need a proper diagnosis first, and then patients can go to the Allergy UK website to find out how to do it properly’.

If symptoms don’t improve after trying medication and avoidance measures, then referral for diagnosis or specialist allergy services from an allergist or immunologist is usually required.

Diagnosis is usually confirmed by objective evidence of sensitisation to a specific aero-allergen through either specific IgE blood testing or skin prick testing. Skin prick testing involves applying a drop of allergen to the forearm and pricking through it – a positive result typically produces a wheal and flare reaction within around 15 minutes.

Treatments

In terms of treatments options, experts say that most hay fever patients can be managed effectively in primary care with second-generation antihistamines and intranasal corticosteroid sprays.

Antihistamines

Ms Knight advised that a non-sedating, long-acting oral antihistamine – such as cetirizine, fexofenadine, or loratadine – is the first-line treatment for mild-to-moderate seasonal allergic rhinitis and should be taken regularly rather than on an as-needed basis.

Meanwhile, she noted that first-generation antihistamines such as chlorphenamine should be avoided due to their sedative effects and short duration of action. Notably, antihistamines only address histamine-driven symptoms such as rhinorrhoea and nasal, eye, or skin itch, and have minimal effect on nasal congestion.

Professor Durham echoed this, warning against first-generation antihistamines, such promethazine and chlorpheniramine, which can cause drowsiness, obstructive sleep apnoea, and have even been linked to road traffic accidents.

Of the second-generation options, he recommended loratadine as a first choice due to its non-sedating profile. He added that cetirizine, while effective, causes sedation in around 20% of patients.

Meanwhile, fexofenadine, Professor Durham said, matches cetirizine for efficacy but with no drowsiness. However, he added that it is only available at the effective dose on prescription.

Professor Durham noted: ‘The only situation where sedating antihistamines may be helpful is for sedation in children with eczema who are experiencing intolerable itch, because as well as treating the itch, it also helps sedate them at night. But I wouldn’t use them otherwise.’

Intranasal steroids

Ms Knight described regular use of intranasal steroids as the mainstay of treatment for persistent nasal congestion, reducing inflammation and mucous production. ‘These should be used alongside oral antihistamine and saline nasal rinsing – taking care to use saline rinsing before and not after the nasal spray,’ she noted.

Professor Durham added that while intranasal steroid sprays are broadly similar across brands, combination sprays containing both an antihistamine and a steroid – such as dymista and ryaltris – are particularly effective.

Stephen Foster, general practice pharmacist and respiratory and allergy specialist, said: ‘Patients want to use decongestant nasal sprays such as sudafed and otrivine, which are ineffective against allergies. My personal preference is a corticosteroid nasal spray such as dymista, which has recently become available over the counter.’

It’s important to distinguish intranasal steroid sprays like dymista and ryaltris from fast-acting decongestants like sudafed and otrivine, which contain xylometazoline and oxymetazoline.

Not only is there scarce evidence for the use decongestant nasal sprays against allergies, but the Medicines and Healthcare products Regulatory Agency recently reduced maximum use from seven to five days – citing adverse effects following prolonged use.

In comparison, intranasal steroid sprays like dymista and ryaltris can be used for several months, as long as they’re prescribed by a doctor.

Mr Foster also highlighted that many patients use nasal sprays incorrectly. The correct technique involves leaning slightly forward, then taking a slow, gentle breath in through the nostrils – not a forceful sniff – when dispensing the spray.

Other treatments

Saline nasal irrigation can help wash allergens from the nose and is well tolerated in both children and adults. For eye symptoms, Ms Knight recommended over-the-counter mast cell stabiliser drops such as sodium cromoglycate, or tear supplement drops.

‘If mast cell stabiliser eye drops are not effective in controlling eye symptoms,’ said Ms Knight, ‘an eye drop containing both a mast cell stabiliser and antihistamine – such as olopatadine – can be prescribed.’

Both Ms Knight and Mr Foster reiterated that oral decongestants such as pseudoephedrine are not recommended, highlighting the lack of evidence to suggest they have benefits against allergies.

The future of allergy care: ‘it’s now!’

When asked what the future of allergy care could look like, Professor Durham said: ‘There have been major developments in allergen immunotherapy – it’s not the future, it’s now.’

He explained: ‘What this treatment involves is giving – either by injection or, via the sublingual route using tablets – grass pollen extracts or dust extracts, or indeed cat extracts, in increasing doses in order to induce a state of immunological tolerance.

‘You can dramatically reduce symptoms by starting at very low doses and increasing the doses to a maintenance level.’

Professor Durham continued: ‘If you take the treatment for three years – one tablet a day under the tongue – you get long-term disease remission for at least two years after stopping the treatment. There’s nothing else that can do that. If you stop the antihistamine or the intranasal steroid, the symptoms come back within days or weeks.’

Ms Seal highlighted that these immunotherapies are ‘really amazing’, but unfortunately, they are usually reserved for people with the very worst symptoms, because they’re expensive and there aren’t enough clinics or clinicians to administer them widely.

Professor Durham also conceded that while the treatment is effective for around 80% of patients, subcutaneous treatment must be routinely done in a health-care setting, which can impact adherence for some patients.

For this reason, an increasing number of patients are choosing sub-lingual treatment. However, Professor Durham said that around 40–75% of patients receiving sub-lingual treatment will suffer from side-effects such as itching and swelling of the tongue – some individuals will be unable to tolerate treatment for that reason.

Outside of immunotherapy, Ms Seal noted that there are some other treatments being researched that have real potential. These include: ‘some that smuggle allergens into the immune system in order to retrain it not to react – one group is using nanoparticles to do this, and another is using a plant virus.’

She said: ‘Even if [these new therapies] turn out to work, we are still going to need many more people to administer them, and more clinics and more expertise.’

Ms Seal added that the new National Allergy Strategy, which launched on 20 April, ‘calls for much better, wider training of non-specialists who can treat people with allergies really well locally, without them having to be referred to a centre a long way from their home, or having to sit on a waiting list for months or years.’

A version of this article was first published on our sister title, The Pharmacist.