Doctors are reporting a change in the way the flu is presenting as a new strain spreads across the UK. Hospital admissions linked to the flu rose sharply at the beginning of the year, with an average of 2,924 people a day admitted by January 4. Four hospital trusts have declared critical incidents, citing ongoing and intense pressure on services. These include three trusts in Surrey and one in Kent.Surrey Heartlands Trust said winter pressures had been made worse by a rise in flu and norovirus cases. NHS national medical director Professor Meghana Pandit said the situation remains difficult, with hospitals seeing another increase in patients admitted with flu and other respiratory infections last week.She said it is still vital for people to seek medical help when needed and reminded the public that there are many chances to get vaccinated against flu. Health Secretary Wes Streeting also stressed that flu can be dangerous, especially for older adults, young children, and those with existing health problems. He urged everyone who qualifies to get their flu vaccine as soon as possible, calling it the best form of protection.Doctors Report Unusual Symptoms As New Flu Strain Spreads Across The UKDoctors say this latest flu strain appears to be causing different symptoms. The virus, known as subclade K, is a variant of the A H3N2 type of influenza.Dr Mark Loafman told NBC Chicago that many patients are experiencing much higher fevers than usual. He said the fever can last five to seven days, which is longer than people typically expect and is a cause for concern.In some cases, doctors say the fever does not respond well to common medicines such as paracetamol or ibuprofen. Lung specialist Dr Juanita Mora said this strain is linked to very high temperatures, a severe and persistent cough with heavy phlegm, vomiting, diarrhoea, and widespread joint and muscle pain.Doctors have also noticed a rise in stomach-related symptoms, including nausea and vomiting, often referred to as gastrointestinal or GI issues. Dr Loafman said that, based on what doctors are seeing, adults infected with the subclade K strain seem to be showing more signs of GI illness than usual.According to the NHS, flu symptoms usually appear suddenly and tend to be much more severe than those of a common cold. While most people start to recover within about a week, the illness can feel particularly harsh while it lasts.Key Symptoms of FluThe main symptoms usually begin abruptly and include:A sudden high temperature of 38C or higherBody aches affecting muscles and jointsExtreme tiredness or exhaustionA dry coughA sore throatHeadachesProblems sleepingReduced appetiteNausea, vomiting, or diarrhoea, which are more common in childrenHow To Treat Flu at HomeMost people can deal with flu symptoms at home without needing to see a doctor. The NHS advises the following self-care measures:Rest and Sleep: Allow your body time and energy to fight off the infection.Stay Warm: Use extra layers or blankets to maintain body warmth.Hydration: Drink plenty of fluids to prevent dehydration. Your urine should be pale yellow or clear.Pain Relief: Paracetamol or ibuprofen can help reduce fever and ease aches. Avoid taking combination flu medicines alongside paracetamol tablets, as this can lead to taking too much.Sore Throat Relief: Gargle with salt water if you are an adult, or have hot drinks such as lemon and honey to ease discomfort.