On the clinical encounter with 'zebras' - the science and art of rare diseases.

Taught since medical school to concentrate on the more common disease entities, physicians may become insensitive to the possibility of encountering a rare disease ("zebra") or even an unusual presentation of one. The personal experience of one of the authors prompted this article, presenting an alternative view. We stress the need to carefully consider at times even rare diagnostic entities and their potentially unusual presentations. We discuss practical approaches to the special problems of these patients who are under-represented in the literature. In particular, using computerized searches when facing patients with unexplained symptoms, and adopting an honest, supportive attitude when uncertainty persists, seems important.