IU performs during her concert at the Seoul World Cup Stadium in Seoul, Sept. 20, 2024. Courtesy of EDAM Entertainment

K-pop singer and actor IU is drawing public attention for a rare ear disorder after worsening symptoms of patulous Eustachian tube (PET) dysfunction forced her to postpone her upcoming album release and cancel a scheduled September concert.

With news of her ear condition already having disrupted her highly anticipated comeback plans, many are asking what exactly PET dysfunction is and why it poses such a devastating setback for a vocalist.

On Monday, the 33-year-old artist opened up about her ongoing struggle on the fan communication platform Berriz.

"While it does not affect my daily life, the symptoms persist day and night, making it difficult to maintain my condition when singing," IU wrote, apologizing to fans for the schedule changes.

PET dysfunction occurs when the Eustachian tube, which connects the middle ear to the back of the nose and usually remains closed except during swallowing or yawning, stays abnormally open.

This allows air and sound to flow continuously into the middle ear, causing autophony, a condition where a person hears their own voice or breathing abnormally loudly inside their head.

"Patients hear their own voice echoing as if they were in a cave, making it an extremely agonizing and critical condition for singers who are sensitive to sound," Jung Jin-sei, a professor at Severance Hospital, previously explained.

"If the feeling of fullness in the ears or echoing temporarily disappears when bending forward at 90 degrees, there is a very high possibility of PET dysfunction."

Medical experts say the condition is rarely present from birth and is most often triggered by external factors, particularly sudden weight loss and fatigue. When people lose weight rapidly from extreme dieting, the fat and muscle tissue surrounding the Eustachian tube shrink, preventing the tube from closing properly and keeping it stuck open.

Because of this, the disorder is relatively common among young, slim women. Professionals who rely heavily on their voices, such as singers, teachers and call center agents, are especially sensitive to the symptoms. Physical activity can also worsen the condition, as heavy breathing during exercise echoes much more loudly inside the head.

Treatments range from simple habit changes, like gaining weight and drinking more water, to surgery or medical procedures for severe cases if basic care doesn't help.