Flu is a common viral infection that’s spread by sneezes and coughs, said the NHS.
While people can catch flu all year round, it’s more common in the winter months.
Cold and flu symptoms tend to overlap, and it can be difficult to tell which is which.
But, there are four key warning signs that differentiate a cold from the flu, it’s been revealed.
Having a moderate to high fever is one of the signs that your cold is actually the flu, said The Online Clinic’s GP, Dr Lizzie Kershaw-Yates.
While it’s not the case for everyone, most cases of the common cold don’t include a fever, she said.
You should also look out for the shaking chills, and severe fatigue. Some patients with a cold may have muscle aches, but are unlikely to feel drained of energy.
Persistently feeling nauseous, or actually vomiting, could both be signs of the flu, added the GP.
“One of the biggest differences between the two illnesses is how quickly your symptoms develop,” said Kershaw-Yates.
“If your symptoms gradually develop over a few days, then it’s likely you just have a cold. If they came on suddenly and severely – you could have the flu.”
If you think you have a cold you should use over-the-counter medications to relieve symptoms, including antihistamines and decongestants.
It’s also crucial to drink plenty of fluids and avoid dehydration, she added.
There’s usually no need to see a doctor if you have a cold, and it usually clears up within seven to 10 days.
But, you should speak to a doctor if your cold hasn’t improved after a week, if you develop a high fever, or if your fever doesn’t go down at all.
Most people with flu won’t need to see a doctor either, she said. But, people who are at risk of some complications should call their doctor when their symptoms first develop.
Call a doctor if you have flu and have a weakened immune system, are pregnant, are are over 50 years old.
“You should also see a GP as soon as possible if you find that your flu symptoms are becoming severe,” said Kershaw-Yates.
“See a doctor if you show any signs of pneumonia which include trouble breathing, chest pain, green mucus when coughing, high persistent fever or a severe sore throat.
“At risk groups such as the elderly and those with compromised immune systems are normally vaccinated against seasonal flu. The seasonal flu vaccine is a ‘best guess’ of what the virus circulating in the community is going to look like.”
You can get the flu jab at your local GP, or at some pharmacies. Most children between the ages of two and 10 receive the flu vaccination on the NHS. Boots UK is now offering the vaccine to those aged 10 to 16 for the first time.