The number of people with allergies has risen continuously over the past 60 years, with higher incidence rates among children. Today, more than one billion people worldwide are affected by allergies, and it is expected that by 2050, 1 in 2 people will suffer from allergies1.


Rapidly increasing prevalence

The increasing prevalence and intensity of allergies is a trend that has continued in the industrialised world for more than 60 years. Allergies currently affect over 13% of the world’s population, and an estimated 20% to 30% of the developed world2.

Allergies impact quality of life and can trigger asthma

The limitations resulting from the body’s reaction to allergens are multifaceted but share one common theme: the patient’s quality of life is no longer what it used to be.
People who are sensitised to aeroallergens develop allergic rhinitis with symptoms such as a runny nose, itching, watery eyes, respiratory congestion and fatigue. A possibly less well-known and often underestimated consequence is that allergies put people at a greater risk of developing asthma.

People with allergic rhinitis are three times more likely to develop asthma than other people, and the risk for patients with house dust mite-induced allergic rhinitis is about six times higher than those whose allergic rhinitis is caused by grass pollen2.

Too many patients are not treated

Allergic rhinitis affects approximately 10% to 30% of adults and 40% of children2. Only approximately 12% of people suffering from allergic rhinitis are treated with allergen immunotherapy (AIT) products due to low awareness among primary care prescribers, a complex treatment pathway and a market that is dominated by lower cost symptomatic treatments. AIT is the only treatment that addresses the underlying cause of allergy and may provide both rapid (within a few weeks) and long-lasting improvement of all symptoms, whereas symptomatic treatments (such as antihistamines and corticosteroids) temporarily relieve some allergy symptoms.

With a modest proposal rate, the AIT market is still underdeveloped, representing approximately €1bn or 12% of the global allergic rhinitis market and is expected to grow by 2% annually in the coming years3.

Market growth is expected to result from an increased awareness of respiratory allergies, easier access to allergists, the expanded range of administration modes as well as a growing middle class in developing countries that will gain access to medical treatment.


Innovation in science and technology is creating new medical opportunities

Biologics, gene therapies and other new molecularly targeted compositions are starting to deliver on their promise to enable more precise diagnostics and more tailored treatments. The increasing development of patient-friendly treatments (shorter treatment lengths, ease of use) should improve AIT penetration in the allergic rhinitis patient population and their adherence.

In addition, advances in the areas of genetics and informatics are driving a transformation in our understanding of the disease. Innovations in technology also present opportunities to address the growing volume of regulatory requirements more efficiently and more effectively.

Rise in allergies gaining attention from payers, providers and regulators

As more patients seek treatment for their allergies, the AIT industry has gained greater attention from the healthcare community. Healthcare providers are seeking more clinical evidence related to the safety and effcacy of AIT; payers are tightly controlling access and increasingly requiring data about the economic benefit to maintain coverage for treatment; and regulatory bodies are intensifying their scrutiny and enacting more stringent requirements of biologics manufacturers.


1. Bousquet, J., Burney, P.G., Zuberbier, T. et al. (2009). GA2 LEN (Global Allergy and Asthma European Network) Addresses the Allergy and Asthma Epidemic. Allergy. 64: 969–977
2. World Allergy Organization. “White Book on Allergy: Update 2013” — 3. Market size (€1bn) and expected growth (2%): global data and internal estimates share of AIT market in the global allergic rhinitis market (12%): Visiongain report 2018.




Why is climate change an important aspect of allergology?

Climate change affects the disease pathology both directly and indirectly. Temperatures, humidity or atmospheric pressure have a direct effect on the disease; humidity, for example, has a significant impact on asthsma. And, by impacting the risk factors for allergic diseases (pollen, mould, allergen proliferation, chemical air pollution), climate change has an indirect influence on allergic diseases and can contribute to the development of childhood asthma or cause severe complications for people with asthma.

Increased pollution levels linked to soil desertification, forest fires, urbanisation and traffic, fossil fuel production, etc. also affect the molecular structure of pollen. Air pollution, by damaging the outer membrane of pollens, causes pollens to release microparticles which harm our mucous membrane and bronchial airways and can, in turn, trigger asthma. Pollens become increasingly allergenic as a result of climatic conditions and increased CO2 levels; when CO2 increases, plants produce more pollen and, notably, pollen with a higher allergenic potency.

We have been studying the evolution of allergens in relation to climate change for many years now. For example, for pollen, botanists have collected a lot of data and pollen count series that show the evolution linked to climate change. Pollens are increasing, plants are migrating geographically, depending on the climate, and adapting their molecular structure to go where it is better for them in terms of pollination with longer seasons and earlier in the year (February instead of March). We also have similar data on moulds and mites.

What role does the exposome play on the health of each individual?

I have been working on the exposome for quite some time now. The exposome is the set of environmental risk factors (e.g. physical, chemical, biological, dietary, climatic or geographical, social, economic or contextual) an individual is exposed to throughout his or her entire life and the interactions of which may or may not lead to the development of a pathology. Obviously, each individual's genetic profile plays a role in the development of pathology but not all diseases are monogenic and, in particular, asthma and allergies are multifactorial and multigenic.

In allergology, we are quite advanced on these issues because we have been studying them for a long time. All the environmental factors potentially involved are taken into account and treated by big data, artificial intelligence, etc. We have made more progress in the field of allergic diseases than in other disciplines because it is a multidisciplinary science involving clinical observations as well as all the sciences related to exposures (allergens, botany, etc.).

To this set of environmental risk factors should also be added the consideration of crucial periods in the life and development of the individual (pre-conception, pregnancy, first 100 days, adolescence, menopause, old age etc.).

Why take an interest in this and consider these interactions?

Because we are dealing with multifactorial diseases and we can thus identify a risk profile that is useful for both understanding allergic diseases and their prevention. Moreover, this work has made it possible to identify avoidable exposomes on which we can act through prevention measures.

We must not forget that the World Health Organisation insists on the importance of identifying the “vulnerable populations”, i.e. individuals who are particularly weakened by inequalities and who must be taken into account by the public authorities in order to be protected.




Call to action: Air pollution, asthma, and allergy in the exposome era

Isabella Annesi-Maesano,
MD, PhD, DSc, Cara Nichole
Maesano, PhD, Benedetta
Biagioni, MD, Gennaro D’Amato,
MD, Lorenzo Cecchi, MD, PhD