• nail
• A dark area that becomes wider or changes
• Bleeding without an obvious injury
• Persistent pain or swelling around a nail
• The nail separating from the nail bed
• Significant nail destruction
• Rapidly changing pigmentation
• A persistent unexplained growth around the nail

A new or changing dark streak can occasionally be associated with melanoma of the nail unit, although there are many benign causes of nail pigmentation as well

That is one reason a changing dark streak deserves professional assessment rather than internet diagnosis.

Can Nutritional Deficiencies Cause Nail Changes?

 Nutrition