Dr Amir Khan has urged hay fever sufferers to take their antihistamine tablets now as he issued a warning over winter hay fever. The doctor, a regular guest on ITV morning show Lorraine, told today's host Christine Lampard that people should take their tablets now to reduce their symptoms when summer comes.

The doctor, who also appears regularly on Good Morning Britain, issued the advice as he warned people that they could be suffering with winter hay fever without realising. The TV doctor said some of his patients tell him they have been telling him they have had a cold for three months - but this is not what they are suffering from.

Instead, he said many people have winter hay fever without realising it. He told viewers: "So many people come and see me and say i’ve had a cold for three months. This cold has not gone away, but actually they haven't got a cold, they've got winter hay fever - an allergic reaction.

"So instead of to pollen they're allergic to things in their home, so things like house dustmite, mould, that kind of thing that’s around the house. And so they get the symptoms of what feels like a cold but is slightly different.

"The mucus is clear rather than this kind of pale green or yellow colour. They may still get sinus pain, they may still get a runny nose - that tickly cough because the mucus drips back - but it’s actually this winter hay fever."

He said it could also be something else. "The other thing it could be, and this is really common, is silent reflux, and we've mentioned this before, but this is where acid manages to get all the way up to your throat and irritate your airways and your mucus membranes and make you produce more mucus, cough.

"It feels like a cold, it doesn’t feel like acid reflux. You don't get any of those heartburn symptoms up here [points to throat].

"It feels like a cold. So is it winter hay fever or is it silent reflux? Let us do some detective work as your doctors and we can figure that out."

Then he turned to his warning to hay fever sufferers who have issues in the summertime.

"And the other thing I will say to you is if you do suffer with hay fever in the summertime, now is the time to start taking your antihistamines. Don't wait until your immune system ramps up - it's much harder to bring it down.

"Start it now, stop that ramp up, take it regularly, reduce your symptoms in the summer."

What is hay fever and what are the symptoms?

According to the NHS, hay fever is a is "a common allergy that causes sneezing, coughing and itchy eyes. You cannot cure it, but there are things you can do to help your symptoms, or medicines you can take to help."

They warn hay fever can last for weeks or months, unlike a cold, which normally goes away after 1 to 2 weeks. That tallies with what Dr Amir Khan said today.

The NHS says that symptoms are "usually worse between late March and September, especially when it's warm, humid and windy. This is when the pollen count is at its highest."

• pain around the sides of your head and your forehead
• sneezing and coughing
• itchy throat, mouth, nose and ears
• a runny or blocked nose
• itchy, red or watery eyes
• feeling tired
• loss of smell
• headache

There is currently no cure for hay fever and you cannot prevent it, the NHS says. However, you can do things to ease your symptoms when the pollen count is high. See the NHS website for more.