Hay fever can drive you up the wall - with constant sneezing and irritability.

       But for some, the annual snot-fest has started early.

       Unlike seasonal allergies in spring - which are triggered by grass and flower pollen - February allergies are often due to tree pollen, indoor allergens or changes in temperature.

       While most associate hay fever with spring and summer, some trees begin releasing pollen as early as January, peaking in February and March, depending on weather conditions.

       Some have already been complaining about sneezing over the social media forums.

       A user @Hemlock Dreams wrote on X, formerly known as Twitter: “The last couple of times I've been out, I've been sneezing and wheezy, like I've got a cold.”

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       According to the UK Health Security Agency (UKHSA), many studies have suggested that some types of pollen and other allergens could be released earlier in the year and for longer durations as temperatures rise.

       For some types of pollen, this may mean levels high enough to trigger hay fever as early in the year as January or February.

       Last year, the incidents were reported as early as in February.

       The UKHSA stated: "Research suggests that with increasing temperatures, oak and grass pollen seasons may start even earlier, meaning that some allergy sufferers could begin to experience hay fever and other reactions as early as January/February.

       "The UK is also facing a threat from changes in the geographical distribution of allergenic plants, due to climate change, with invasive species such as ambrosia (common ragweed) being on the watch list. A single ragweed plant can produce a billion grains of pollen per season and its pollen causes strong allergic reactions."

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       Pollen grains are tiny particles produced by flowering plants for reproductive purposes - some plants transfer pollen to other flowers of the same kind by means of insects, while many rely on wind to carry pollen grains through the air to their destination.

       Pollen contains proteins and a significant number of people have an allergic reaction to these proteins (most commonly hay fever, but also allergic asthma and eczema).

       In the UK, it is estimated that every year, millions of people feel the ill effects of pollen exposure.

       Meanwhile, the UKHSA, the Met Office, and several universities have collaborated on researching various aspects of pollen.

       According to the research, careful cutting regimes of grass could make a significant difference in the amount of grass pollen produced, with more work needed in this area to find out the health impact of such a change.

       - Sneezing and a runny or blocked nose

       - Itchy, red, or watery eyes (allergic conjunctivitis)

       - Itchy throat, mouth, nose, or ears

       - Coughing

       - Fatigue and feeling generally unwell

       - Headaches and sinus pain in severe cases