Tree pollen and pollen food syndrome
The two main types of pollen which affect the majority of people with hay fever are tree pollens and grass pollen.
The types of trees most likely to release pollen that triggers hay fever are alder, birch, hazel and horse chestnut. The first tree pollens of the year typically release and cause hay fever symptoms in February, but sometimes as early as January.
Pollen counts are influenced by several factors including climate and this can mean the start of the pollen season varies from year to year.
Birch pollen and Pollen Food Syndrome
In spring birch tree pollen is highly allergenic and planting birch trees near homes or in school grounds can sensitise susceptible people.
75% of people with birch allergy also have pollen food syndrome (also known as oral allergy syndrome). This is because the main allergen in birch pollen (Bet v 1), is highly cross-reactive to many plant foods. It’s been shown that birch pollens contain proteins of similar structure to those present in many different fruits, vegetables, nuts and even spices.
People who have pollen food syndrome will usually experience mild itching and/or swelling of all or part of the lips, tongue, mouth or throat but reactions can sometimes be severe and include nausea and vomiting. Symptoms usually start within minutes of eating and settle down within an hour.
If you think you may have pollen food syndrome, you should speak to your GP. They may refer you to a consultant allergist to ensure you receive a correct diagnosis and appropriate treatment.
For more information on pollen food syndrome, please click here.
Allergic Eye Disease
Many people suffer from allergic conjunctivitis, either seasonally (seasonal allergic conjunctivitis) or all year round (perennial allergic conjunctivitis).
The main symptoms are itching, burning, watering and redness of the eye, and puffiness of the eyelids. The cause is exposure to a substance to which a person has become allergic, known as an allergen. For most of those affected seasonally, these symptoms are part of their hay fever, and the cause is the same. Tree pollens (or other pollens from grass, weeds or shrubs) land on the eye surface and trigger the release of substances such as histamine, which cause the symptoms.
For more information on allergic eye disease, please click here.