Cracks & Lines on Nails: What Do They Mean?

Having strong, smooth nails is about much more than beauty. How your nails look and feel can clue you in on your overall health and well-being. If you are wondering what those discolorations or lines on your nails happen to mean (and if they are a cause for concern), read on. Board-certified dermatologist and nail expert Dana Stern, MD helps us take our nail health into our own hands.

White Lines on Nails

White spots, streaks and faint white lines on nails are nothing to worry about. But some white lines can be of concern. Dr. Stern breaks down the different types of lines on your nails that indicate it’s time to see a dermatologist.

Mee’s Lines: White bands that follow the contour of the lunula (half moon). Arsenic poisoning is the classic cause; however, there are also many other potential medical causes including certain vitamin deficiencies and infections.
Beau’s Lines: Horizontal depression in the nail plate due to growth arrest of the nail from illness, fever or trauma.

Dark Lines on Nails

Dark brown or black stripes down the length of the nail could be benign pigmentation, moles or freckles. For example, splinter hemorrhages are black, length-wise lines that look like splinters but are most commonly due to trauma. So while it is normally nothing, “the pigmentation can be a melanoma of the nail,” says Dr. Stern, “which most commonly appears on the thumb, index finger and big toenail.” Dr. Stern recommends seeing a dermatologist if there is a single pigmented band (brown or black) on a single nail or if you see a brown pigment surrounding the nail—as these could be an indication of skin cancer.

Onycholysis (Nail Separating From the Bed)

Those at-home manicures could be doing more harm than good. Nails separating from the nail bed is a telltale sign that you need to take a step back from vigorously cleaning under the nail. Other possibilities? “Trauma (skiing, tennis, hiking) or certain diseases (psoriasis),” Dr. Stern tells us and recommends a strict irritant-avoidance regimen.

How to Treat: Dr. Stern tells us: No nail polish, no filing and no cosmetic treatments for a few weeks, keeping the nail clip short. Be sure to keep the nails clean and dry by avoiding soaking them in water. Doctor’s orders!

Onychauxis (Thickening of the Nails)

Our nails thicken as we age. And while many may think a thick nail means fungus, thick and misshapen nails can appear from repetitive friction on the nail over time. “In fact, only 50 percent of ‘abnormal’ looking toenails are fungal. Proper diagnosis is key!” says Dr. Stern.

Brittle Nails

Cracked, split, thin nails: all in the same family. Brittleness is an all-too-common complaint, and, unfortunately for us, there are many potential causes. Genetics and aging play a huge role, as well as anything that puts a strain on the nails throughout time. This could be due to:

Excessive exposure to chemicals such as dish soap and nail polish remover.
Water. “Nails are extremely absorptive of water, even more so than skin,” says Dr. Stern, “and too much water exposure can put tremendous strain on the delicate nails.”
Certain medical conditions: hypothyroidism, Raynaud’s Disease and protein deficiency. Dr. Stern adds that in these cases, they usually result in a sudden change in nail quality.

How to Treat:

Wear gloves for household chores like washing dishes.
Avoid excessive use of hand sanitizers containing alcohol.
Do not remove nail polish more than once a week and do so with a non-acetone nail polish remover.
“A diet with an adequate amount of protein will help,” Dr. Stern explains. Added bonus? “A 2–3mg [supplement] of biotin daily may help with nail growth and strength.”

Discolored Nails

Yellow nails? Discolored looking? Your nail polish is usually the culprit! Yet nails can also turn color due to stains from tobacco, henna or self-tanning products. A non-cosmetic cause can be yellow nail syndrome. Yellow nail syndrome nails appear thick and yellow/green in which case it’s time for a visit to the doctor’s office.

How to Treat:“Nail polish stains can be lightened by using a dilution of hydrogen peroxide,” Stern explains. “Combine three to four tablespoons of hydrogen peroxide and one-half cup of water and mix them well. Soak your nails in the solution for two minutes. Using a soft toothbrush, gently scrub your nails. Then rinse them with water. Repeat two to three times during the week if needed.”