Bambin Gesù

Pollen and mould: 40% of children suffer, molecular tests to map allergens

Pollen seasons go well beyond spring while symptoms become earlier and more prolonged: customised therapy with immunotherapy

by Ernesto Diffidenti

18 March 2026

3' min read

Translated by AI

Versione italiana

Key points

Tougher diagnoses with overlapping seasons
New molecular technologies for allergen mapping
Temporal, mould and new pollen
The Bambino Gesù data

3' min read

Translated by AI

Versione italiana

One of the most obvious effects of climate change is the anticipation of pollination. Plants that used to start releasing pollen in mid-February can now do so as early as January or, in some cases, even during the Christmas period. At the same time, allergy seasons tend to extend well beyond the traditional spring with grasses sometimes having a second flowering after the summer.

The result is an allergy season that progressively extends cwith direct effects on children's health and with increasingly shorter break periods for the allergic children.

In Italia, pollen allergies are among the main causes of allergic rhinitis in children, recalls the Bambino Gesù Children's Hospital. Studies of the school population indicate that sensitisation to at least one airborne allergen affects almost 40% of adolescents, while allergic rhinoconjunctivitis affects about 18%. Considering that in 2024 there were about 7 million children between 0 and 14 years of age in Italy, it is estimated that pollen-allergic children may be between 1.2 and 2.7 million and of these, 7,500 come to the outpatient clinics of the Bambino Gesù for pollen allergy, while another 2,500 are evaluated in allergy counselling during hospitalisations or visits for other diseases. About 1,000 patients are being treated with allergen-specific immunotherapy.

'Climate change has completely changed the way we observe and manage pollen allergies,' explains Alessandro Fiocchi, head of Allergology at the Bambino Gesù. Pollen seasons are longer and less distinguishable from each other and this means that allergic children have earlier and more prolonged symptoms'.

Diagnoses more difficult with overlapping seasons

This transformation has important consequences for diagnosis, especially in children who are often sensitised to several pollens at the same time. When pollen seasons overlap, it becomes more difficult to identify the pollen responsible for the symptoms based on the child's medical history alone.

"Many children today are allergic to several pollens and, with seasons overlapping more and more, the mere observation of symptoms is no longer sufficient to identify the allergen responsible," Fiocchi emphasises. "This is why we are using increasingly advanced molecular diagnostics that allow us to precisely identify individual allergenic components.

New molecular technologies for allergen mapping

To cope with this new complexity, molecular diagnostics are playing an increasingly important role alongside traditional tests - such as skin testing and the search for specific IgE in blood.

These examinations make it possible to identify not only the pollen responsible, but also the individual allergenic molecules within it. Some of these components are in fact associated with more intense forms of allergy or an increased risk of developing asthma.

The Laboratory of Clinical Analyses at the Bambino Gesù Children's Hospital is among the first to have developed advanced diagnostic panels that analyse hundreds of allergens simultaneously, offering a true 'map' of the patient's sensitisation and allowing personalisation of therapies, including allergen-specific immunotherapy.

Temporal, moulds and new pollens

Climate change is also favouring the spread of allergenic plant species in areas where they were previously rare or absent. One example is ragweed, originally from North America, which has spread to many parts of Europe in recent decades and is now responsible for numerous cases of respiratory allergies in northern Italia and other regions of the country.

Rising temperatures, changes in humidity and more frequent extreme weather events can also influence the presence of moulds in the environment. In some cases, phenomena such as so-called 'thunderstorm asthma' can occur: during particularly intense thunderstorms, pollen can fragment and release large quantities of allergenic particles into the air, possibly leading to peak asthma attacks.

The Bambino Gesù data

An increase in cases has also been observed in recent years. In 2019, there were approximately 5,000 paediatric respiratory allergy patients followed by the Bambino Gesù, with 670 children undergoing immunotherapy. After a reduction in admissions between 2020 and 2021 due to the pandemic, there was a strong upturn in diagnoses between 2022 and 2023, followed by a further increase between 2024 and 2025, in parallel with longer and more intense pollen seasons.Every year, allergy clinics also intercept about 5,800 new cases of pollinosis: about 370 children begin immunotherapy while over 5,500 patients are managed with other therapeutic strategies and followed by the family paediatrician.

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