Singing the blues: is it really cyanosis?

A patient with a bluish tinge to the skin is alarming to a medical provider. Such a patient may be severely hypoxemic, which is a medical emergency. However, there are other causes of bluish coloring, both acute and chronic. We present a case of a patient who was referred for care because he appeared blue. We discuss common and uncommon causes of bluish appearance and suggest a diagnostic approach to such patients.