Melanoma can develop under and around both fingernails and toenails. While it’s considered rare, accounting for 3.5% of melanoma cases, it’s more common in people with skin of color, and is often diagnosed at a more advanced stage than melanoma on the skin. Melanoma usually starts as a dark spot or streak on the nail, typically the big toe or thumb, but it can be any digit. What starts as a small spot or streak may continue to grow, cause the nail to separate from the bed, or cause skin darkening near the nail. If you notice any new or changing spot or a spot that won’t heal, see your doctor. Learn more about skin cancer under your nails.