The announcement from America is certain to cause alarm to two generations of fans around the world. Dylan celebrated his 56th birthday last week, but to his admirers he has, in the words of one of his most beautiful songs, stayed "forever young".
His famous "never-ending tour" which sees him performing constantly, allied to a mystique engendered by years of elliptical statements and a refusal to give interviews, has cast him as one of the few Sixties' legends who has embraced neither middle age nor middle of the road.
Dylan complained of chest pains after celebrating his birthday last Saturday and was admitted to hospital straight away. He was diagnosed as suffering from histoplasmosis, a relatively rare disease. An infection of the sac around the heart, it produces symptoms similar to tuberculosis.
Dylan is being treated in an undisclosed hospital in the United States and is likely to remain there for some time, his British spokesman said. His UK tour to Cork, Glasgow, Newcastle, London, Birmingham and Sheffield has been cancelled.
Dylan's agent, Barry Dickens, confirmed the singer had been admitted to hospital at the weekend. He added he was waiting to speak to doctors in Los Angeles to try to find out the condition of the singer.
"It was his birthday at the weekend and he complained of chest pains," Mr Dickens said. "He went to hospital where he was admitted for treatment. In the 10 years I have represented him he has never complained about chest pains once."
"The infection is potentially fatal. He will remain at the hospital until his condition is stable and he has improved."
Though described by Mr Dickens as "potentially fatal", the disease afflicting Dylan is an obscure one whose effects are clearly variable.
A British specialist in the field said last night that the condition was rarely fatal but could be serious, tending to affect primarily the lungs.