In a tearful interview with presenter Janette Manrara, Dowden added that she was “heartbroken” about the decision.
“Being back with the Strictly family was the best rehab.”
She said she hoped she would be “back dancing in some capacity, maybe in a group number, by the end of the series”.
Fellow pro Lauren Oakley will take her place, pairing up with Dowden’s celebrity partner, JLS singer JB Gill.
Oakley stood in for Dowden last Saturday, with the pair performing a Bruno Mars medley and scoring 39 points.
Dowden said Gill was “so talented, like he picks up the routine so fast, it’s unbelievable”.
“But, most importantly, he just loves to dance.
“He’s enjoying his magical, Strictly journey, and honestly, I can’t wait to watch them just continue, in JB’s words, he’d say – ‘That’s dope’.”
On Instagram, Gill praised Dowden for her “fight and determination” and said he had “nothing but admiration” for her.