Understanding Green/Black Spots on Feet: Causes & Treatment

Green or black spots appearing on the feet that won't wash off are most likely caused by a fungal infection called tinea nigra, which is not serious. It is caused by a fungus called Hortaea werneckii, which lives on healthy skin but can appear as black spots on the tops of the feet and under toenails. It can also affect the hands, arms, and other body sites.

While it is mostly seen in warmer climates and in those who wear shoes without socks for long periods, tinea nigra is generally harmless. It is treatable with antifungal creams, powders, or lotions and normally does not cause complications or recur.

However, if you have spots on your feet that concern you, it is best to see a healthcare professional to rule out any other potential causes or receive appropriate treatment.