Speculation about the 74-year-old royal's fingers was ignited in 2021, when a photograph of him pulling a pint of beer during an engagement in South London gave fans a glimpse at his swollen hands. Taking to Twitter, one fan wrote: "I've never noticed the hands of Prince Charles until this photo! Is he ok? They are so swollen."
The King himself has taken a lighthearted approach to his hands' condition in the past, having jokingly referred to himself as having "sausage fingers" in a letter to a friend after his son, William, the Prince of Wales, was born.
He wrote: "I can't tell you how excited and proud I am. He really does look surprisingly appetising and has sausage fingers just like mine," as quoted in the biography Charles, The Man Who Will Be King by Howard Hodgson.
In fact, King Charles III's fingers and hands have since become some of the most Googled terms for the royal in the UK - but what is the cause for the apparent inflammation?
Why are His Royal Highness' fingers so big?
His Majesty's swollen fingers could be for a number of reasons, from temporary fluid retention due to a sudden change in temperature to arthritis. Other causes of a "sausage" like finger can be high blood pressure, or even having a diet that is high in salt.
Arthritis is a disease that affects the tissues of your joints. The chronic inflammatory disease causes the joint lining to swell, causing pain, stiffness and loss of function.
According to the NHS, other symptoms can include warm red skin over the affected joint as well as weakness and muscle wasting. There is no cure for arthritis, though medication and physiotherapy can help alleviate the symptoms.
Though it's not confirmed that the King suffers from a form of arthritis, other royal fans have noticed his hands appear particularly swollen when he travels abroad to warmer climates.
According to Cornwall Live, King Charles III himself is reported to have also made reference to his enlarged digits during a trip to Australia in 2012, dubbing them his "sausage fingers" after hours of flying to the tropical climate.
The symptom of "sausage fingers" is actually linked to Dactylitis, a secondary disease that can be caused by a number of conditions and infections, most commonly psoriatic arthritis.