Warmer UK climate triggers early allergy alerts and brings the threat of new pollens

Warmer UK climate triggers early allergy alerts and brings the threat of new pollens

A leading expert says highly allergenic birch pollen is already sparking Met Office alerts this week. Grass pollen, the UK’s biggest cause of hay fever, is also likely to arrive this month due to the mild weather. As Britain’s weather warms and new plant species arrive, it’s vital we know which pollens, spores and insects may trigger our individual responses.

The mild, if distinctly wet, winter and spring means the UK’s Met Office has already issued warnings for birch pollen this week. Birch pollen is described as ‘highly allergenic’ by Asthma UK and can trigger allergic symptoms in up to 16% of people. Most commonly, birch pollen will cause hay fever, but it can also trigger allergic asthma, conjunctivitis and even pollen food syndrome (a sensitivity to plant-based foods that can cause a severe reaction).

Unfortunately, this is likely to herald a bad year for allergies, warns a leading expert. Mild weather and a lack of frost mean grass pollens – the main cause of hay fever in the UK – look set to arrive as early as this month, according to the UK Health Security Agency (UKHSA). That’s not the end of concerns about the impact of climate change on UK pollen levels. Higher overall temperatures mean new plant species are arriving from warmer countries, introducing new potential allergens for people who have not been previously exposed to their pollens.

Dr Avinash Hari Narayanan (MBChB), Clinical Lead at London Medical Laboratory, says: ‘Britain’s warming climate means we all need to get used to an earlier start to the hay fever season and to prepare for new pollens from warmer climates, as new species of plants and trees move northwards.

‘A new study published in the journal “Science of the Total Environment” has analysed rising temperatures in central England over the last 52 years and their impact on allergenic pollen. It has found rising temperatures have been associated with earlier seasons and increasing intensity for some pollens. Warmer seasonal average temperatures were associated with higher amounts of birch pollen, as well as an earlier start-of-season for birch and grass pollens.

‘Ironically, some measures being introduced to counteract global warming could also  increase our exposure to potential allergens. To help meet the UK’s target of offsetting carbon emissions, the Government plans to increase woodland cover in the UK from 13% to 19% by 2050. Fast-growing, non-native conifers are being recommended by some scientists. The introduction of new trees could expose us to new pollens.

‘With rising overall pollen levels and the arrival of new species, it’s important everyone knows their own potential allergy triggers. In allergy testing, the primary type of antibody looked for is Immunoglobulin E (IgE). IgE is produced by the immune system in response to exposure to an allergen. When someone is allergic to a substance, their immune system mistakenly identifies this harmless substance as a threat and produces IgE antibodies specific to that allergen.

‘These antibodies bind to the surface of cells involved in the body's immune response. Upon subsequent exposure to the allergen, these cells are triggered by the allergen-bound IgE to release histamine and other chemicals, leading to an allergic reaction with symptoms including itching, swelling and difficulty breathing. In rare cases, these responses can lead to anaphylactic shock, a potentially life-threatening reaction.

‘How can we learn which pollens and substances may trigger each of us as individuals? Allergy testing was once costly and difficult to access, but the evolution of immunology and technology has vastly improved things. Today, a single finger-prick blood test will identify a wide array of potential allergic triggers, including pollen, pet hair and both plant and animal-derived allergens. For example, London Medical Laboratory’s Allergy Complete is the UK’s most comprehensive allergy test, analysing 295 allergens.

‘As species from warmer climes become established in the UK, more of us will become exposed to new pollens. That’s why the Allergy Complete test covers not just typical British trees, but many non-native varieties too. These include pollens from trees as diverse as Arizona cypress and mountain cedar, the latter being a notorious trigger for “cedar fever” allergy in parts of America.

‘The test also measures our reaction to grass, weed and flower pollens, as well as a wide variety of insect venoms, including those produced by bees and wasps, which can prove fatal. Everything from dust mites to fruit, eggs, nuts, fungi and moulds are also covered. It can be taken at home through the post, or at one of the many drop-in clinics that offer it across London and nationwide in over 120 selected pharmacies and health stores. For full details see: https://www.londonmedicallaboratory.com/product/allergy-complete