This lady explains it quite well....
Histrionic personality disorder (HPD) is a mental health condition marked by intense, unstable emotions and a distorted self-image. The word “histrionic” means “dramatic or theatrical.”
For people with histrionic personality disorder, their self-esteem depends on the approval of others and doesn’t come from a true feeling of self-worth. They have an overwhelming desire to be noticed and often behave dramatically or inappropriately to get attention.
People with histrionic personality disorder often don’t realize their behavior and way of thinking may be problematic.
Histrionic personality disorder is one of a group of conditions called “Cluster B” personality disorders, which involve dramatic and erratic behavior.