Hay fever pills could cause little-known side effect as doctor issues warning

With hay fever season kicking off this week and the pollen count currently high in many states, sufferers are using all kinds of remedies, as well as medication to help ease their symptoms.

Around 67 million Americans are affected by seasonal allergies, with many turning to antihistamines, nasal sprays and decongestants to find some relief.

However, one doctor has revealed that antihistamines in particular can have a little-known side effect that's important to be aware of.

Antihistamines work by blocking the impact of histamine in the body, which is usually released when the body detects something it perceives as being harmful.

The NHS explains: "It causes blood vessels to expand and the skin to swell, which helps protect the body.

"But in people with allergies, the body mistakes something harmless – such as pollen, animal hair or house dust – for a threat and produces histamine. The histamine causes an allergic reaction with unpleasant symptoms including itchy, watering eyes, a running or blocked nose, sneezing and skin rashes."

Antihistamines can help stop the symptoms if taken before coming into contact with the substance, and can reduce the severity if taken afterwords.

Millions of people suffer with hay fever every year (Getty Stock Photo)

But there's actually a little-known side effect of taking the pills.

Turns out that antihistamines could actually increase your appetite, with Dr Crystal Wyllie, a GP at ZAVA Online Doctor telling the Daily Mail: "Histamine actually helps suppress appetite in the brain.

"When you take an antihistamine, you're blocking that effect, which may make you feel hungrier than usual. Over time, that can lead to increased calorie intake without you even realising it."

Experts explain that despite the link, any impact on weight is thought to be minimal.

One study from 2020 found those taking prescription antihistamines had a higher body weight, BMI and insulin levels, however Dr Wyllie explained it's important to be open minded about the 'bigger picture'.

"Weight and allergies appear to be linked in a two-way relationship,’ says Dr Wyllie.

"It’s important to look at the bigger picture rather than blaming a single medication."

Some antihistamines have been linked with an increase in appetite (Getty Stock Photo)

If you are concerned, Dr Wyllie explains that certain diet changes can help support your body against hay fever, but warns that this isn't a replacement for medication.

"Food isn’t a replacement for medication, but certain nutrients can help your body respond more calmly to allergens," she explained.

"Think of it as supporting your system from the inside out."

To help manage hay fever with diet, foods rich in vitamin C and omega-fatty acids, such as berries, kale and oily fish are a good starting point.