Episodic unilateral mydriasis and headaches.

When anisocoria is associated with headaches, it usually heralds serious central nervous system pathology such as tumors, aneurysms, or herniation. But when a patient has isolated, episodic unilateral mydriasis and migraine, such a patient may be reassured and further workup undertaken only if symptoms worsen or change. We present a 17-year-old who had severe headaches and episodic pupillary dilation, and review the current literature on the topic.