Hi Heather,
I am also going through one such situation. At times understanding why the other person is behaving that way actually helps. Sometimes people do such things to protect themselves from their own mistakes, so that by highlighting yours their mistakes are hidden. False sense of satisfaction gets created there.

If there is no such thing, try talking to that person directly once – how you feel when he/she does that. Take help of people at office who can support you. Worst case contact HR. No company likes to have employees who demean other employees morale.

If nothing works, Its time to quit this place. !!! But one of the above might help.