The 'Who'd Have Known' singer said that she has been struggling to perform after being diagnosed with laryngitis and bronchitis.
Allen told the Daily Star: "I've had laryngitis and bronchitis for about two months and I've just been doing so many gigs and just not resting.
"I have been to an ear, nose and throat specialist a few times and they stuck a big camera down my throat. It's not very nice."
Allen confirmed yesterday that she plans to take "one or two years off" from music after her remaining live dates.