10/05/2011 05:21 pm ET | Updated Dec 05, 2011

Adele Cancels Tour Due To Illness: But What Is A Vocal Cord Hemorrhage?

British singer Adele has canceled her U.S. tour because of a vocal cord hemorrhage.

She wrote on her blog that she was diagnosed with a hemorrhage -- "which is like a black eye on the vocal chord" -- back in May that caused her voice to "switch off like a light."

Even though she rested for a month after that, Adele wrote that her voice problems started back up again in September, and that she has the hemorrhage again.

She wrote:

The fact is i have never been able to fully recover from any of the problems that ive had and then continue to rest even once im recovered, because of my touring commitments.

A vocal cord hemorrhage is considered a "vocal emergency," according to the Mount Sinai School of Medicine, and can only be healed by resting your voice until it is resolved.

It is caused by the rupturing of blood vessels on the surface of the vocal cord, which then causes blood to fill the vocal cord soft tissues. It manifests as an abrupt loss of voice after a strenuous vocal activity -- like singing or yelling -- and should be treated right away by a doctor, according to the Mount Sinai School of Medicine.

Singing is affected by a vocal cord hemorrhage because the blood makes it difficult for the vocal cords to vibrate, Dr. Gaelyn Garrett, medical director of the Vanderbilt Voice Center, told ABC News. If the hemorrhage, which is like a bruise, isn't allowed to heal, though, it could cause scarring and could permanently affect the voice, ABC News reported.

Garrett told ABC News what happens when one of her patients suffers from a vocal cord hemorrhage:

"I'll put someone on complete voice rest for a week," said Garrett, adding that "complete" means no singing and no talking. "Then I'll check them again in a week to make sure there's no recurrent bleed."

American Idol winner Jordin Sparks was also diagnosed with an acute vocal cord hemorrhage back in 2008, ABC News reported. She was put on vocal rest and had to drop out of a tour with Alicia Keys.