As explained for “Ridged nails” the appearance of vertical ridges are caused by age and pose no threat, in worst cases dehydration and unhealthy blood flow are the main causes for it.
However, any dark lines appearing in vertical ridges causes concern for Melanoma.
Melanoma is a form of skin cancer. Melanoma usually appears to look like a black “Mole”, commonly understood as a cancerous mole. Cancer of this type are extremely lethal.
With a very fast speed of progression, late treatment can be life-threatening. However, with a speedy discovery and operation, this condition can be treated. Therefore, if you find a “mole” or “dark line” appearing on your nails, please visit a medical professional.
Even for rare cases, a speedy discovery and speedy treatment should be encouraged. Melanoma is one of the many possible causes of a symptom. Symptoms can be just a standard “mole” or stain.
Regardless of the situation, a speedy diagnosis from a medical professional is recommended.