Despite being the one who was the costume expert, Pirrina only applies the costume of the haggard old woman on Kachorra, who uses it to take on the persona of Alma.
Kachorra's nickname is puppy dog in Spanish. Natalia Oreiro thought it was cute, and liked that it was with at "K" not a "C" because she isn't a dog.
There is a picture of Natalia Oreiro during her time promoting "Tu Veneno" that is hidden in the corner of Jose's room by the light switch.
The character of Josefina listens to the music of the band Divididos. Kachorra says that is a good band. This is a reference to Natalia Oreiro's real life. She had just gotten married to Ricardo Mollo the lead singer of the band.
This was supposed to be Natalia Oreiro's big return to novellas after not acting for two years. She had finished Muñeca Brava, which was a massive worldwide hit, and decided to focus on her music. She toured for two years, and then decided to return to acting with Kachorra. While the show was not the hit she expected it would be, it was still popular.