What causes numbness of middle toe?

Something localized: It sounds like something related to that foot.See a podiatrist. Root pain (a radiculopathy) is a possibility if other symptoms are present.

Possible Neuropathy: Symptoms of neuropathy can range anywhere from numbness, tingling, or burning sensation, to an uncomfortable painful sensation of the extremities. For some, these symptoms are mild, while for others, they can be severe and disabling. Neuropathy can develop as a result of a pinched nerve, trauma, drug side effect, and some diseases such as diabetes. Get evaluated and professionally treated.