How common is discoloured nails in melanonychia?

Melanonychia describes pigment that creates a brown, grey, or black colour in the nail, often as a stripe running from the base toward the tip. It may affect one nail or several. The pigment can involve the nail plate, the skin beneath it, or the skin beside the nail.

Possible causes include normal pigment variation, repeated injury, medicines, inflammation, and other nail conditions. Rarely, pigment can be linked to melanoma of the nail unit. Colour and pattern need an examination because photographs and home checks cannot establish the cause.

Take dated photographs of the nail in good light and record whether the band is changing in width, colour, or shape. Avoid biting, picking, aggressive manicures, and unprotected chemical exposure. Keep the nail products-free before an examination so the surface and surrounding skin can be seen.

Arrange a clinician or dermatologist appointment for a new pigmented band, pigment in one nail that is evolving, or uncertainty about a longstanding mark. The clinician may use magnification and decide whether monitoring or sampling is needed.

Seek prompt review if a band widens, develops uneven shades, has an irregular edge, or extends onto the skin at the nail fold. New pigment in one nail, especially when it is changing, should not be dismissed as a cosmetic stain.

Get urgent help for severe pain, rapid swelling, pus, fever, or bleeding after injury. These signs suggest an additional nail or skin problem that may require immediate treatment.

Does this pigment pattern fit melanonychia, or could it be staining or injury? Should the nail be photographed for follow-up or sampled? What changes in the band or nearby skin should prompt an earlier appointment?