Korn [ tickets ] frontman Jonathan Davis has contracted a rare blood ailment that will keep him sidelined for several weeks and has forced his band to cancel the remaining dates of its in-progress UK tour.

"This is the short version of what happened," Davis wrote in a letter posted at Korn's website. "I started getting these weird bruises all over my body about two weeks ago. I was getting very weak after the shows so I saw a doctor in London on Friday. He took some blood tests and when the results came in they rushed me to [a London-area] hospital.

"It turned out I have ITP [Idiopathic Thrombocytopenic Purpura]. It's too hard to spell, but basically it's a blood infection where because of an allergic reaction, my blood platelets--the stuff my bone marrow produces to help my blood clot--were really low. I mean, way low. Most humans have between 140 and 400 in their cells. I had 5 ... no joke ... FIVE. If I continued to headbang on stage I could have had a brain hemorrhage and dropped dead on the spot."

Davis went on to say that his platelet count has been going up and that his doctors have told him that he should be able to resume performing in "a few weeks," but that he is unable to perform or travel right now. Doctors should "know more in a day or two," he added.

According to a press release from the band's publicist, "plans call for the band to come back to Europe as soon as possible when their schedule permits.

"I want everyone to know that we will do our very best to come back soon to play dates we are unable to play this tour," Davis added.

On Saturday, Davis' bandmates--bassist Reginald "Fieldy" Arvizu, guitarist James "Munky" Shaffer and drummer David Silveria--performed as scheduled at the UK Download Festival. The trio played an abbreviated set that featured guest vocalists Corey Taylor (Slipknot, Stone Sour [ tickets ]), Dez Fafara (Devildriver), Jesse Hasek (10 Years), Benji Webbe (Skindred), M. Shadows (Avenged Sevenfold) and Matt Heafy (Trivium).

Korn has been on the road to support last year's "See You on the Other Side," which features the hit singles "Coming Undone" and "Twisted Transistor." Last month, the band issued "Live on the Other Side," a DVD that captures its Nov. 25, 2005 performance at New York City's Hammerstein Ballroom.

Despite Davis' current condition, Korn still expects to headline this year's Family Values Tour [ tickets ], according to the group's publicist. The North American festival trek launches July 27, and features fellow hard-rock acts Deftones [ tickets ], Stone Sour, Flyleaf [ tickets ] and Dir en Grey.