Perfectionism seems to have its roots in those messages young children think they hear from important adults in their lives. There is also pressure from the media and from peers that contribute to perfectionistic thinking (i.e., the "Barbie body" phenomenon). And I have a hunch that some children's temperaments make them more susceptible to perfectionism. These temperament qualities can be noticed as early as infancy in babies who react strongly by exploding from calm to full-blown wailing in a matter of seconds.
-Reva Friedman-Nimz, "Done to Perfection," Understanding our Gifted, Summer 2006
Friedman-Nimz discusses perfectionism as a continuum with three dimensions: beliefs, explanations, and expectations. In her article, she also includes a brief questionaire to determine where on this continuum one falls, especially in regard to these dimensions.
Friedman-Nimz states that there are three irrational beliefs held by those who are plagued with dysfunctional perfectionism:
1 - It is necessary to be loved by and approved of by everyone (important to that person).
2 - One's competence and achievement are related to self-worth.
3 - It is catastrophic when things don't go as they should.
I've not only been a parent of a perfectionist but still deal with it frequently myself.
I think that gifted children in particular are susceptible to the second point. So often, they are viewed as weird by other children and adults. When someone does recognize their gift, they feel as though that is the entire reason why someone would like them. Without their gift, they feel like they'd be nothing. (Ironically, if they weren't gifted, they may not be shunned as often by peers.) The child's self-worth is determined by their abilities, and they need their abilities to earn the love of those they care about.
An article in New York Magazine entitled, "How Not to Talk to Your Kids: The Inverse Power of Praise," discusses how adults tend to react to children. When parents or teachers tell a child they are smart rather than emphasizing their effort, the child will tend to think things should come easily. They will become discouraged and quit if they don't. Likewise, Friedman-Nimz discusses telling a child, "Good girl!" versus, "Good job!" sets up this dynamic. It creates a situation where children feel their inherent abilities are necessary to gain the love and acceptance of those around them. Telling them that their effort is recognized helps the child feel cared for whether or not they reach the brass ring. They will be more likely to make an effort int he future.
Finally, dealing with the third point takes some patience and modeling on the part of the parent. Some children inherently react with anger and frustration to an unexpected outcome. The only way to deal with this, in my experience, is to explain your thought processes to the child about how changes are not always bad and sometimes may be good. It takes time, but it can be highly effective. If a parent models an easy-going attitude to changes, the children will pick up on it...eventually.