The sovereign and Prince Philip were then supposed to visit Rome on Wednesday and Thursday, where they were to meet Italian President Giorgio Napolitano.
They were due to receive a ceremonial welcome and attend a private lunch, before visiting ancient monument the Pantheon.
On a statement published on his website, the Italian president wished the monarch a speedy recovery and thanked her for her attempts to visit him in Rome before he leaves his post in mid-May.
Queen Elizabeth was last admitted to hospital 10 years ago.
She had an operation at King Edward VII’s Hospital to remove cartilage from her left knee on December 12, 2003 and had some benign facial lesions removed at the same time.
She was last forced to pull out of an investiture ceremony — where she presents honours including knighthoods — in October last year due to a bad back.
On Thursday she presented a host of British Olympic stars including heptathlete Jessica Ennis and long-jumper Greg Rutherford with honours.
The monarch celebrated her diamond jubilee in 2012, marking her 60 years on the throne. This year further ceremonies will be held to mark the six decades since her 1953 coronation.