Melanonychia on a toenail: what should you know?

The colour can run lengthwise from the base toward the tip, or appear as a broader area of pigment. A single toenail may be affected after repeated pressure, a knock, or irritation from footwear. Several nails can show pigment in people with naturally deeper skin tones or from medicines and other health conditions. The band itself is a sign, not a diagnosis, and its appearance over time helps a clinician interpret it.

Take a clear photograph in good light and record when you first noticed the change. Compare the band as the nail grows, without scraping, filing, bleaching, or applying strong home remedies. Wear shoes with enough toe room and avoid picking at the nail. A dermatologist can examine the nail, the surrounding skin, and the nail base; further testing may be considered when the pattern is unclear.

Arrange a dermatology assessment if a new band is widening, becoming uneven, changing colour, spreading onto the skin beside the nail, or occurring with splitting, bleeding, pain, or a persistent sore area. Seek prompt care for rapid change or a dark mark that does not grow out with the nail. These features do not identify the cause by themselves, but they deserve direct examination.

Ask what features were seen on examination, whether an old injury or medicine could explain the pigment, whether monitoring is suitable, and what change should bring you back sooner. If a procedure is discussed, ask what part of the nail is sampled and how healing will be managed.