While your nails may not be your first stop for clues about how you are doing, they can reveal a lot about you health.
What do healthy nail look for? Dana Stern M.D. says that “normal” fingernails must have white tips and a subtle shine. , Assistant Clinical Professor of Dermatology at Mount Sinai Medical School ,, tells SELF. Your nails should be flesh-colored. This means they should be tan, pink, or brownish. Dr. Stern says that the cuticles are healthy and moisturized. “Hangnails are absent.”
If your nail color, shape, or structure starts to look a bit odd for reasons beyond normal wear–say, you spent all weekend deep cleaning the house or you’re really due for a manicure–then it’s possible your fingernail health may indicate a deeper issue with your overall health, Dr. Stern says. Here are the most common nail problems that potentially signal something that’s more than skin-deep, according to dermatologists.
1. There are small dents on the nail’s surface.
Small dents on the surface of your nail bed are called pitting, and when they show up with no apparent pattern or reason, this could indicate an autoimmune disorder, conditions in which the body mistakenly starts attacking healthy cells, leading to inflammation.
For example, pitting is typically connected to psoriasis (a skin condition that causes scaly patches to appear on the skin) and psoriatic arthritis (a type of arthritis that commonly affects people with psoriasis). The phenomenon could also be linked to connective tissue disorders such as Reiter’s syndrome, which is a form of arthritis that is triggered by infection elsewhere in your body. When pitting shows a regular pattern, it can be a sign of alopecia areata, a type of hair loss caused by an autoimmune response, according to the Mayo Clinic.
If what you’re noticing isn’t quite pitting but is instead deep lines or grooves in your nails, you might be dealing with a phenomenon known as Beau lines. While some lines can be normal on nails, Beau lines are noticeable and run lengthwise along the nail. These can appear after really intense stress to your nail makes it stop growing (or grow more slowly than usual) for some time, according to the American Academy of Dermatology Association (AAD). Causes of this can include high fever, which is why there’s been concern about “COVID nails,” or what some experts think may be Beau lines manifesting after COVID-19 infection.
2. Your nails look like spoons.
This is called koilonychia, and it can be a completely normal age-related change to your nails, Dr. Stern says. But it may also indicate iron-deficiency anemia or other disorders in which iron is not metabolized correctly, like hemochromatosis and Plummer-Vinson Syndrome, which happens after long-term, chronic iron-deficiency anemia1. Your doctor may recommend treatment if you are diagnosed with low iron levels. “Anyone who suddenly develops spoon-shaped nails should have a workup by their physician,” Dr. Stern says.
3. Your nails are white.
When the part of the nail closest to the cuticle is solid white and the distal part (the farthest section that’s still attached to the nail bed) is pink, this is called half-and-half nails, which Dr. Stern says is also called Lindsay’s nails.
Experts are still investigating the possibility that Lindsay’s nails could be genetic. Sometimes, however, half-and-half nail color can indicate a more serious condition such as chronic kidney disease. When two-thirds of the nail is completely white and just a sliver on the end of the nail bed is pink, it’s called Terry’s nails2. “This can be indicative of cirrhosis, congestive heart failure, or diabetes mellitus,” Dr. Stern says.
4. You have black or brown stripes on your nails.
A dark brown or black stripe along your nail, or brown pigments surrounding the nail, will most often be benign moles or pigmentation. This is most common in people with darker complexions because they tend to have more pigment-producing melanocytes in their skin and nails3. When the melanocytes are stimulated, usually through trauma to the cuticle (aggressive and repetitive cuticle pushing, cutting, picking, or biting), “these cells begin to produce pigment, appearing as a brown, length-wise band in the nail,” Dr. Stern explains.
But this could indicate melanoma. Dr. Stern states that melanoma is most commonly associated with skin cancer. However, it can also occur in the nails. “The thumb, index finger, and great toenail are the most common digits to have melanoma.”
Since it’s very difficult to distinguish early melanomas from benign pigments, “it is imperative to see a dermatologist for a thorough exam and consultation” if you notice this symptom, Dr. Stern says. If the dark streak is growing or changing in any way, such as widening or becoming darker, this is especially important. This is also key to keep in mind if you have dark skin, as you can be more vulnerable to getting melanoma on your hands and feet (which can present on your nails). Nail melanoma tends to be diagnosed late, but if you catch it early, it’s often treatable.
5. Your nails are yellow.
Dr. Stern points out that nail polish can cause nails to turn yellow most often. This is a relief! But it’s also an instance where you can tell more about your health from your nails and signal that you have a very rare issue called yellow nail syndrome, according to the National Organization for Rare Disorders. Dr. Stern explained that yellow nail syndrome causes nails to appear thickened and have a yellow-to-green hue. Dr. Stern explains that yellow nail syndrome can cause nails to appear thicker than normal and lack a cuticle. Dr. Stern explained that bronchiectasis refers to a condition where the airways become narrower, flabby, and scarred due to damage. It can be caused by a medical issue such as an infection. This can also affect nail growth. Dr. Stern explains that yellow nail syndrome can also be caused by bronchiectasis, which is a chronic condition. Problems with the lymphatic system can impact circulation, preventing “oxygen, nutrients, and blood from getting to extremities,” Dr. Stern explains, and sometimes causing yellow nail syndrome.
6. Your nails become blue or green.
Discolored nails that are blue or green can indicate a range of health concerns, depending on the specific color. According to the AAD, having blue nails could indicate that you don’t have enough oxygen. This can be caused by many medical conditions such as pneumonia. However, blue nails can also be a sign of poisoning. This is known as argyria or silver poisoning. It only occurs if your body is constantly exposed to silver. If you have a bacterial infection, your fingernail might turn greenish-black. The medical name for this is paronychia, and it can happen if bacteria gets into a cut near your cuticle and infects the skin under your nail, according to the Cleveland Clinic. Your skin around your nails may become inflamed and swollen. Typically, you’ll need to see a doctor to get an antibacterial medication or else the infection will become worse.
7. Your nails are developing in a downward direction.
If your nails are curving down and have a noticeable rounded edge–kind of like upside down spoons–this could be a sign of a condition called clubbing, according to Mount Sinai. Clubbing can cause your tips to appear reddened or swollen from the clubbing. It can feel like your nail beds aren’t attached properly to the bed, and may even feel soft.
Clubbing can be caused by a deficiency in oxygen, which can also occur with other lung or heart diseases. Although lung cancer is the most common, it can also be caused by congenital heart disease or infections of the heart and lung. It may also be a sign of IBD or another inflammatory problem in the GI tract, like celiac disease.
8. Your nails may separate from their nail bed.
This condition, called onycholysis, is typically painless and is usually more likely to happen if you have longer nails. The most common cause is simply trauma to the nail, such as too much nail filing or irritation from chemicals used during manicures.
Onycholysis can also be caused by a fungal infection in the nail, and it’s sometimes associated with psoriasis, according to the AAD. Dr. Stern says that sudden separations can occur in multiple nails and could be indicative of hyperthyroidism, a hormone condition that affects your metabolism.
There may be many reasons why your nails are separating from their nail beds. Your doctor might not be able explain it if you only have a physical exam. So, you may have additional testing, such as a blood panel, to figure out what’s going on.
9. There are ridges on the middle of your nails.
If you notice ridging or stripes on the middle of your nails (this sort of looks like a washboard) and y