Toe nails getting black lines running from top to bottom. Also under nails in hands are turning slightly dark recently.

Question

In some cases, black lines on the nails may be caused by melanoma. Most commonly, dark stripes down a person's nail are due to a symptom known as linear melanonychia. The condition occurs when pigments in the nail known as melanocytes make excess pigment. This causes the nail beds to darken. Fingernails are made by living skin cells in your fingers. So a skin condition such as eczema may lead to fingernail ridges. Skin dryness can also cause these ridges. If your body is low in protein, calcium, zinc, or vitamin a, a deficiency can sometimes be revealed by ridges in your fingernails.

Sajeev Kumar · Accepted Answer

In some cases, black lines on the nails may be caused by melanoma. Most commonly, dark stripes down a person's nail are due to a symptom known as linear melanonychia. The condition occurs when pigments in the nail known as melanocytes make excess pigment. This causes the nail beds to darken. Fingernails are made by living skin cells in your fingers. So a skin condition such as eczema may lead to fingernail ridges. Skin dryness can also cause these ridges. If your body is low in protein, calcium, zinc, or vitamin a, a deficiency can sometimes be revealed by ridges in your fingernails.