Hay Fever: Causes, Symptoms & Treatments
Hay fever is estimated to affect more than 10 million people in the UK[1], typically when the pollen count increases during the warmer and sunnier months of spring and summer.
Also referred to as allergic rhinitis, hay fever describes a group of symptoms that predominantly affect the nose and eyes and can be alleviated through certain lifestyle habits and the use of hay fever treatments.
This guide comprehensively covers the causes of hay fever and how its symptoms can be alleviated, based on the current understanding of this condition and the latest scientific research.
What is hay fever?
Hay fever is a common allergic condition triggered by an immune response to allergens such as pollen.
Hay fever symptoms are typically experienced when the body’s immune system mistakenly identifies allergens as being harmful and produces antibodies in response[2].
These antibodies subsequently send a signal to widen the blood vessels and ramp up the production of inflammatory chemicals such as histamine.
Hay fever may be broadly categorised as:
- Seasonal hay fever, which is typically caused by allergic sensitivity to airborne pollen, mould spores, and grass. Seasonal hay fever is most likely to occur in the months between the start of spring and the start of autumn, as this is when the pollen count typically increases each year.
- Perennial hay fever, which is usually caused by dust mites, pet hair and mould. As the name suggests, perennial hay fever can occur all year round.
What are the symptoms of hay fever?
The most common symptoms of hay fever are:
- A runny or blocked nose
- Itchy, red or watery eyes
- An itchy throat or mouth
- Sneezing and coughing
- Headaches
- Fatigue, which can occur as a result of a lack of sleep and/or poor sleep quality due to common hay fever symptoms such as nasal blockages
The frequency, duration, and severity of hay fever symptoms depend on the individual’s pollen immunity and the current levels of pollen in the air (known as the ‘pollen count’).
The daily pollen count may be tracked using our pollen count forecast tool which accounts for weather patterns and annual pollen production from 15 species of plants.
What causes hay fever?
Hay fever is primarily caused by allergens such as:
- Pollen
- Mould or fungi
- Dander or pet fur
- Dust mites
- Cigarette smoke
- Perfume
Hay fever can also be caused by certain genetic factors. For instance, if an individual’s parents have allergies, then they are more likely to experience allergy symptoms as well, including hay fever.
This is because inherited genes can predispose individuals to an overreactive immune system, particularly through certain genes that regulate the production and response of immunoglobulin E (IgE), a key antibody in allergic reactions[3].
In some cases, the children of parents with allergy-related diseases can be more likely to develop hay fever, even if the parents do not suffer from hay fever.
It is also worth noting that other respiratory and skin conditions like asthma and eczema, which are also often hereditary, do not increase the risk of developing hay fever.