Doctors warn: This change in nails may be cancer! Don't take it lightly

When you cut your nails, have you ever noticed the subtle changes in your nails? In fact, nails also reflect the health of the body to a certain extent, such as the sudden growth of black lines on the nails...

Previously, a netizen shared a picture of his nails and asked for help: "Am I sick? A black line suddenly appeared on my nails in the past half month. At first, I didn't pay much attention to it. I thought it was dyed by a watercolor pen. But half a month later, I found that it was not a watercolor pen, but a growth inside the nail shell."

Image source: Weibo screenshot

Many netizens said that they also have it on their nails!

Image source: Weibo screenshot

What is this black line and is it something to worry about?

Putting aside the nonsensical factors such as clothing fading and drawing with markers for fun, there are actually some people who suddenly grow black lines on their nails, and the reasons behind this are a long story.

Let’s start with how nails grow

Have you ever noticed the white half-moon on your nails? There is a white half-moon-shaped structure at the base of the nail, scientifically called the "lunula" . The active cells that produce nails, also called "nail matrix", are just below this half-moon and the skin at the base of the nail.

Image source: Photo by the author

Don’t worry if you can’t see the half-moon . As long as the nails are growing normally, the half-moon exists objectively, it’s just hidden under the skin.

Image source: Photo by the author

The nail matrix continuously generates new nails at the root of the nails and pushes the old nails forward . This process allows our nails to continuously grow and renew towards the fingertips, which is also the reason why we need to trim our nails frequently.

Based on the growth principle of nails, we can easily understand that if there is bleeding under the nail, the formed blood scab will be slowly pushed forward by the new nail - I believe many people have had this experience.

As long as the nail matrix that produces the nail is not damaged, the nail can be restored to its original state even if it is pulled out - anyone who has had nail extraction can speak for this.

On the contrary, if the nail matrix suffers physical trauma, abnormal blood supply, malnutrition or other damage, the nails that grow during this period will also be abnormal.

Black lines on nails

Whether it is a blood scab or an abnormal nail, if these abnormal parts are slowly pushed to the front, it means that the nail matrix has returned to normal after experiencing a brief abnormality, and the abnormality is just an episode in the normal nail growth process.

If the black vertical line on the nail runs continuously from beginning to end, it means that there is a problem at the origin of nail growth , and the problem persists. There may be many reasons leading to this result.

Case 1: Simple activation of nail matrix melanocytes.

Normal nails are white and translucent, which is the color of the nail cells without pigment. There are silent melanocytes in the nail matrix that produces nails . If these melanocytes are activated for various reasons, they will produce melanin to dye the nails, and the nails will grow black lines like ink leaking from a printer.

Image source: Weibo screenshot

Factors such as inflammation (such as chronic paronychia), fungal infection (such as onychomycosis), trauma (such as onychophagia, shoe compression), tumors (such as Bowen's disease), drugs (such as lamivudine, chloroquine, arsenic, thallium, mercury, psoralen, etc.), pregnancy, and systemic diseases (such as Addison's disease, systemic lupus erythematosus) can all cause simple activation of melanocytes in the nail matrix, causing black lines to grow on the nails [1].

Case 2: Melanocyte hyperplasia

The mechanism of black nails in this case is the same as the previous one, both of which use melanocytes to continuously color the nails and produce black lines. However, there are some variables in the increase of cells.

If normal new cells replace old cells, it is metabolism; if too many new cells are produced, but their growth is relatively slow, their position is relatively fixed, and they do not cause damage everywhere, it is a benign lesion; if cell proliferation is out of control, they replicate rapidly and colonize everywhere, it is a malignant lesion or cancer.

Melanocyte proliferation that causes black lines on the nails can also be benign or malignant. Common benign lesions include freckles and nail matrix nevus, while malignant lesions are mainly nail melanoma.

Early nail melanoma is very similar to benign lesions in appearance, so distinguishing between benign and malignant lesions is a challenge for clinicians. In addition to fully understanding the medical history and related symptoms, doctors sometimes have to use dermoscopy, tissue biopsy and other methods to further determine the specific conditions of the lesions and give corresponding treatment measures.

By now, you should have discovered that the principle of black lines on nails is easy to understand, but the possible reasons behind it are too complicated. So if we or our family members are unfortunately affected, it is actually risky to judge by ourselves, and it is safest to go to the dermatology department for help.

References

[1] Tosti A, Piraccini BM, de Farias DC. Dealing with melanonychia. Semin Cutan Med Surg. 2009;28(1):49-54. doi:10.1016/j.sder.2008.12.004

[2] Leung AKC, Lam JM, Leong KF, Sergi CM. Melanonychia striata: clarifying behind the Black Curtain. A review on clinical evaluation and management of the 21st century. Int J Dermatol. 2019;58(11):1239-1245. doi:10.1111/ijd.14464

Planning and production

Author: Doctor Feidao Duanyu

Review | Cheng Fang, Chief Physician of Dermatology Department, Xingtai People's Hospital, Hebei Province, Feng Jun, Deputy Chief Physician of Dermatology Department, Sinopharm Tongmei General Hospital

Planning丨Yang Yaping

Editor: Yang Yaping and Wang Mengru

Proofread by Xu Lailinlin