I was reading an article on the Millenials generation the other night... narcissism happened to be discussed. That aside, no, I don't really think it is healthy in general, though there probably is a healthy amount for the average human. Think of it this way - every human is a narcissist to a certain degree, but it is the people that an extremity that really have problems.

"inordinate fascination with oneself; excessive self-love; vanity"

By definition it's self-love to a degree that's not healthy. It's definitely different from self-confidence, which is (generally) positive.

High self-esteem and confidence is good but by definition narcissism is an extreme obsession with oneself, and it is classified as a personality disorder. Most of those are not good.

I'll be the dissenter here. What's not healthy in an extreme obsession with oneself? The state of being a narcissist, in and of itself, is not unhealthy. Perhaps we would view it as a psychiatric problem, but I think it all depends on what that obsession pushes them to do. I don't think that it's true to say that, 100% of the time, narcissism is unhealthy. And as long as there exists a single instance where it is not unhealthy, yes, it can be viewed as "healthy narcissism." If it comes at the cost of a relationship with another person, I don't think that's necessarily unhealthy. People who aren't narcissistic choose to do that all the time. If it comes at the cost of a job or a person's livelihood, then perhaps it is.