Asthma and allergies affect millions in the UK and abroad. Understanding what drives allergic reactions, both inside the body and in the wider environment, will strengthen the ability of public health policymakers to address and limit the impact of these conditions. Here, Professor Sheena Cruickshank introduces ‘Britain Breathing’, a mobile phone app that can help individuals understand their allergies better, and give scientists a clearer picture of allergy and asthma across the country.

• Allergies and asthma are caused by the inappropriate reaction of the immune system to perceived threats, such as particles of pollen and dust.
• Environmental factors such as pollution can worsen symptoms.
• Mobile phone apps, such as Britain Breathing’ can help track and monitor allergy symptoms, and combine them with environmental data to better understand their causes.
• Better data will enable health policymakers to adapt to the growing challenge of asthma and allergies across the world.

For people in the UK, June hails the start of the glorious British summer, but for many, the reality of struggling through weeks and months of seasonal allergies is upon them. In the UK, approximately one in four people live with asthma and seasonal allergies i.e. hayfever (allergic rhinitis) and asthma. Asthma alone is estimated to affect 5.4 million people across the UK and allergies are the most common chronic conditions in Europe.

The culprit underlying all the suffering allergies and asthma cause is the immune response. The immune response has developed to be able to deal with an array of disease causing germs but when the immune system goes rogue, it can itself cause diseases, including allergy.

Allergies are defined as an inappropriate immune response to something harmless it should be ignoring- we call these triggers allergens. The immune response to allergens triggers activation of specialised immune cells (called ‘mast cells’) that release an arsenal of chemicals, including histamine. Histamine and other chemicals trigger mucus production, muscle contraction and recruitment of even more immune cells to the site which causes inflammation. The actions of all these immune cells are what causes the symptoms those of us with allergies and asthma are so familiar with.

An allergy, if not well managed, carries an increased risk of also developing asthma. Asthma is a long term lung condition that causes sensitivity of the airways and around 80% of asthma sufferers are thought to have allergy-induced asthma. In asthma, the airways become inflamed and narrow on exposure to certain triggers, which can be common allergens such as pollens, house dust mites or pets. This, in turn, leads to difficulty in breathing.

Allergies and asthma have a hugely detrimental effect on daily life. Disability-Adjusted Life Year (DALY) is one way to quantify the burden of disease from both its effect on mortality and well-being, with one DALY being roughly equivalent to one lost year of “healthy” life. The total DALYs across a population give you a snapshot of the burden of that condition for a population, and asthma is linked with 23.7 million DALYs globally, making it one of the 30 most significant conditions world-wide.

Building a better picture of UK allergies with ‘Britain Breathing’

Many people do not know what triggers their allergies and there is a shortage of qualified clinical immunologists able to diagnose the problems. Tracking and monitoring symptoms of allergies can be really helpful in both helping to identify the allergens triggering the reaction as well as monitoring the symptoms to help with their management.

We have developed a free mobile phone app called Britain Breathing that enables users to record their symptoms in a simple and straightforward way. The data is shared anonymously with the project team. Using the app enables users to consider their allergy causes, track the days they are better or worse and hopefully be able to better manage their allergy as a result, by either avoiding triggers or using appropriate medication.

This large data set (capturing information on timing and location of allergy symptoms) is combined with other publicly available data (such as weather, pollen or pollution statistics) to help us build a better understanding at a national level of allergy and allergy triggers.  From these data, we can build a clearer picture of the pattern and frequency of allergy incidence across the UK.

Meeting the challenge of asthma and allergy

One of the biggest concerns now is that incidence of allergies and asthma have been increasing on a year by year basis. For example, the World Health Organization have estimated there are 300 million individuals living with asthma worldwide which will increase to 400 million by 2025. The reasons for this increase are not clear and genetics alone are unable to account for such a rise. Anticipating the likely growth of populations with asthma and allergies, and mapping them to the places where cases are most likely to increase, should be an immediate priority of public health planners at national and international level.

The environment is thought to play a critical role. Air borne microbes, different pollens, pollutants from cars and industry or in the home may all be combining to create an allergenic cocktail to both trigger and even worsen symptoms. Lots of studies have shown that fine particulate matter are associated with severe asthma attacks and a need for hospitalisation. Particulate matter is a complex mix of both biological and chemical factors and unpicking which are most damaging is of critical importance. New pollution sensors and cross-disciplinary research bringing together diverse teams of scientists are enabling researchers based in the Manchester Environmental Research Institute to start to address such questions.

Health inequalities also have a huge impact on allergies and asthma and the number of severe attacks. A recent survey showed that almost double the people in lower income bands (below £20,000) comparing to those in the highest incomes (over £70,000 PA) suffered more than two asthma attacks in the past 12 months. This adds a further argument to calls for more use of so-called ‘deprivation’ indexes to apportion relevant health and air quality spending – ensuring those who need relief the most, are the ones who will receive it the soonest.

It is also notable that some of the most deprived areas may be nearer sources of pollution such as roads and industry. Indeed, our preliminary analysis of the Britain Breathing dataset that allergy and asthma symptoms tend to be worse in urban areas than they are in the country. Work in the ward of Brunswick in Greater Manchester, funded by UKRI, is partnering with the community and training community-based researchers to explore links between air quality and health.

Postscript: COVID-19, pollutants, and health

During the current COVID-19 crisis and lockdown, there has been a huge difference in both road use and the levels of pollutants. Although domestic car use has reduced, freight has increased as people change their habits, are unable to drive as much but are increasingly ordering online. Greater uses of bonfires and barbeques has also been reported.

Collectively, this change has been associated with a reduction in NO2 from diesel cars but levels of particulate matter have stayed fairly constant.  What does this mean for our health and how does this affect our allergy and asthma symptoms? We are in a unique position to find out as, with the Britain Breathing app, the data collected has an approximate location together with the anonymised allergy symptoms.

The more people that use the app, the better the data we can collect. This data can not only help us, as individuals, to manage our own symptoms, but can help researchers explore the links between the environment and our health. As cities look to develop infrastructure to try and support greener cities and reduced car use, this type of data is absolutely critical to help shape these policies and help us to be as healthy as we can be.

The Britain Breathing team:

Sheena Cruickshank is a Professor of Immunology, Caroline Jay is a reader in Computer Science and Dave Topping is a reader in Environmental Sciences at the University of Manchester and a co-lead of the Manchester Urban Observatory. Dr Ceri Harrop is an expert in public engagement working with Brunswick residents to research health and air quality. All scientists are based at the University of Manchester and the Manchester Environmental Research Institute.

Take a look at our other blogs exploring issues relating to the coronavirus outbreak.

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