The top warning sign for nail health that you should never ignore, according to a dermatologist

Our nails play a crucial role in safeguarding our fingers and toes from injury, while also aiding in gripping objects. Beyond their decorative function, they can reveal a lot about our general health, says Dr. Shari Lipner, a dermatologist at Weill Cornell Medical Center who specializes in nail health.

Conditions like nutritional deficiencies, autoimmune disorders, and even heart or liver diseases can show up through changes in the nails. Dr. Lipner emphasizes the importance of periodically checking your nails and taking breaks from polish to spot any changes in their shape, color, or texture. While many nail irregularities are harmless, they can also signal an underlying health condition.

Important Red Flag: A Dark Vertical Line on Your Nail

One particular nail health warning that should never be overlooked is a sudden appearance of a dark vertical line on the nail, says Dr. Lipner. This condition, known as melanonychia, appears as a dark brown or black streak on the fingernails or toenails, which results from a pigment deposit in the nail matrix.

Though these lines are generally normal, particularly in individuals with darker skin tones, there could be a serious underlying issue. In rare cases, a dark vertical line could be a sign of a nail cancer called nail unit melanoma, Dr. Lipner explains. This form of melanoma, which originates in the nail matrix, often starts as a thin black or brown streak. The risk increases if only one nail is affected or if the line is unique to a single finger or toe.

Why You Should Be Concerned

While most nail streaks are benign and related to aging, injury, or a harmless growth, its essential to seek professional evaluation as the exact cause can't be self-diagnosed. Its critical to have the condition assessed by a dermatologist, particularly if the line develops suddenly or shows any signs of change.

Nail unit melanoma, although rare, is one of the most common forms of melanoma in people with darker skin. Unlike other types of melanoma, its typically linked to genetics rather than UV exposure and is often diagnosed in later stages when it becomes more aggressive. In fact, reggae legend Bob Marley tragically passed away from this form of melanoma, which began in his big toenail.

How to Stay on Top of Your Nail Health

Dr. Lipner suggests regularly inspecting your natural, unpolished nails, which means taking breaks from manicures and pedicures. Using nail polish continuously can make it harder to spot any irregularities, she notes. Aim for a nail check at least once a month to identify any changes or unusual signs in your nails, cuticles, and surrounding skin.

While not all changes in the nails are indicative of a serious issue, its important to be vigilant about signs like streaks, discoloration, growths, dents, ridges, or nail lifting. If any of these appear, its best to consult a dermatologist for further evaluation.

Author: Logan Reeves