Photo by Tristan Perrier.

About 56 million years ago, primates began a complicated evolutionary process moving away from having claws at the end of their digits to having what they have today: nails. Made from a protein called keratin, claws and nails evolved as function necessitated. Hands and feet became refined and capable of much more delicate tasks, and nails were needed to enable those functions. 

Grooming is thought to be one of the reasons for the success of primates as a class of species, as ridding oneself of parasites leads to a longer and healthier lifespan. One theory suggests that as claws began to flatten out and cover the back of the fingertips and toe tips, offspring of those primates with flatter nails lived longer and healthier lives, producing more offspring with flatter claws, and so on, until all primates had nice flat nails, good for removing vermin from skin and hair.

Nails also provide an extra layer of protection and support at the back of the super sensitive fingertips and toe tips, conferring a subtler facility for grasping and manipulating objects. This added dexterity contributed to the brain growth of primates who became more and more adept at controlling features of their environment. So who knows where we’d be without our nails?

Our nails can help us in new ways in the modern world as well. They can give us some clues about our health, based on their appearance as well as their hardness, brittleness, or flexibility.

Giving clues about our health

Some nail anomalies can signal a health concern necessitating a visit with your provider.

Normal and harmless features of the nails include slightly raised ridges extending the length of the nail from cuticle to tip. These ridges may be more common as we age, but are nothing to worry about. Also normal is when the fingertip is injured on the nail side, a resulting bruise may appear and will “grow out” as the nail grows. (Calculating nail growth at a rate of about .14 inches a month for fingers and .07 inches for toes, you can figure out how long it’s going to take that ugly bruise from when your Great Dane stepped on your toes to grow out.)

However, some nail anomalies can signal a health concern necessitating a visit with your provider.

A dark streak running the length of your nail should be checked by your provider or possibly a dermatologist to rule out melanoma, the most dangerous type of skin cancer.

Pitted nails may be an indication of skin disorders such as eczema or psoriasis. They can also be found when a person is suffering from alopecia areata, an auto-immune condition causing hair loss. Nails, hair and skin are all made of keratin in one form or another.

Nail clubbing happens when the fingertips swell, causing the nails to grow over and around the swelling. This can be a sign of low blood oxygen, heart issues, lung disease, or cirrhosis of the liver.

A symptom of iron deficiency anemia, softened nails that turn up around the edges are also known as koilonychia. The same nail appearance can occur when the body absorbs too much iron from food. Sufferers of Celiac disease often have spoon nails.

“Terry’s Nails” causes most of the nail to appear white. This can happen through aging, but also can be a sign of liver issues, diabetes, or congestive heart failure.

Beau lines are deep grooves that run across the nail and are usually a sign that something has caused your nails to stop growing. Chemotherapy can cause Beau lines, as can zinc deficiency, high fever, and poor blood flow to the extremities.

Bluish nails are a sign of low blood oxygen levels.

Yellow nails can be caused by lung disease or rheumatoid arthritis, and can also be a sign of a serious infection resulting from the lack of cuticle at the base of the nail. The cuticle is a caulk-like layer of skin that keeps bacteria and other contaminants out.

Ram’s Horn nails can run in the family and show as an overgrowth of nail that bulges up and away from the fingertip or toe tip. They are often accompanied by poor circulation or psoriasis.

Nail separation occurs when the nail pulls away unnaturally from the fingertip or toe tip underneath it. Some medications can cause this condition, as can some products meant to harden or decorate the nails. They could also be a sign of psoriasis or thyroid disease.

Red half-moons present on the nail can be a warning sign for lupus, heart disease, or arthritis, among other things.

Redness and swelling around the nail or partial lifting of the nail off its bed can be a sign of infection that requires medical attention to treat.

Nails that are half pink, half white can be a sign of kidney disease.

Nail care

Nail care may be simple or may require extra vigilance on your part to maintain good hygiene and health.

Depending on what your hands and feet are exposed to, nail care may be simple or may require extra vigilance on your part to maintain good hygiene and health. Moisturizer may be applied to the nails when using it on your hands and feet. A protective nail hardener may be applied if appropriate. If your nails are a bit weak or brittle, a nutritional supplement of vitamin B7 may be helpful. 

Don’t bite your nails or your cuticles, and leave those hangnails alone. Keep infection-causing germs out, and save your teeth!

Avoid nail polish remover whenever possible. The harsh chemicals are not good for your nails.

Don’t allow your cuticles to be removed when getting a manicure or pedicure, as not having a cuticle can expose you to an infection.

Basic hygiene and common sense are adequate for nail care unless you notice any of the above signs, in which case, make an appointment with your primary care provider. Meanwhile, get back to that activity from which our civilization originally grew and prospered: picking bugs off ourselves and each other. 

Ann Constantino, submitted on behalf of the SoHum Health’s Outreach department.