What should you know about total melanonychia?

Melanin made in the nail unit can colour the growing nail. Pigment may involve one nail or several, and it can look brown, black, or grey. Causes include normal variation, injury, inflammation, medicines, infection, and changes in pigment-producing cells. The appearance alone cannot establish the cause.

A clinician examines the nail, surrounding skin, and other nails, and may ask when the colour began, whether it is changing, and whether there was trauma or a new medicine. Some cases need monitoring; others need sampling to clarify the diagnosis.

Arrange a dermatology assessment, especially if the pigmentation is new, changing, or limited to one nail. Take clear photographs over time, remove nail polish before examination, and bring a list of medicines and relevant medical conditions.

Avoid repeatedly scraping, drilling, or traumatising the nail to remove the colour. Do not self-treat a dark nail with bleaching products, because this can irritate the skin and obscure useful changes.

Seek prompt review if pigment spreads onto the surrounding skin, becomes irregular, widens toward the cuticle, or is accompanied by nail lifting, bleeding, pain, or a persistent lump. Rapid change or a nail change after significant injury also deserves assessment.

Ask what features support the suspected cause, whether dermoscopy or a nail sample is needed, how the nail will be monitored, and what change should bring the appointment forward. Ask how to protect the nail while it grows out.