Cognitive and visual diagnostic errors in dermatology: part 1.

Sir William Osler famously, and ironically, stated that 'Medicine is a science of uncertainty and an art of probability'. The processes by which each physician metes out diagnostic uncertainty and navigates probabilities in dermatology is far from uniform. While certain ubiquitous cognitive and visual heuristics can enhance diagnostic speed, they also create pitfalls and thinking traps that introduce significant variation in the diagnostic process. Discussed in this part of a two-part article are various cognitive and visual heuristics as they pertain to skin disease, with an introduction and special attention paid to the heuristic methods classically applied by dermatologists. How to best address error and improve our thought processes will be addressed in part 2.