Seven Signs of Healthy Nails

Sudden changes in the crescent moon in a short period of time, clubbing of the fingers, inverse nails (spoon-shaped nails), long-term paleness of the nail bed, yellow/grey nails with thickening of layers, abnormal changes in the subungual black line, and recurring periungual redness and swelling. There is really no need to apply the rest of the sayings such as "more crescents means longevity" and "vertical nail lines = bad liver and kidneys".

Let’s talk about the crescent moon that people ask about the most. I usually tell patients that the core logic of looking at nails is always that “sudden changes” are more important than “natural abnormalities.” You have only had one crescent moon since you were a child, and you have eight crescent moons and suddenly only have one crescent in two weeks. They are completely different things. There are currently two mainstream views in the academic community regarding the clinical significance of lunula: most dermatologists believe that lunula are new keratin cells of the nail matrix, which will be exposed more if they metabolize faster. Staying up late, dieting and losing weight, and hormone fluctuations during the menstrual period may cause the size and number of lunula to change. As long as they do not suddenly disappear and pop up within a few weeks, there is no need to worry about it. ； Nutrition scholars suggest that if there are less than 2 crescents for a long time, and you are accompanied by dizziness and dark eyes when you squat down or stand up, it is best to check for iron deficiency anemia. The two statements are not conflicting. The core is that only sudden changes are worthy of vigilance. Oh, by the way, some people asked if the white spots on the nails are due to zinc deficiency? Most of them are caused by minor trauma to the nails. For example, if you pinched your finger when closing the door, it will grow out on its own after a while. It has nothing to do with zinc deficiency or anything like that. Many people have asked, by the way.

Last month, I saw a 40-year-old smoker who was brought in by his family. They said that the front ends of his nails were bulging like small hammers. He didn't take it seriously, saying it was not painful and it didn't hurt, so why spend the money? Later, it was found that he had early interstitial pulmonary fibrosis. Fortunately, he was discovered early. This kind of hyperplasia, hypertrophy, and arched bulge at the end of the nails is called clubbing. It is not entirely related to heart and lung problems. A small number of people are congenital and have been like this since childhood. There is no problem at all. But if it gradually becomes like this in adulthood and is accompanied by chest tightness, frequent wheezing, and long-term coughing, you must have your heart and lungs checked in time. The specificity of this signal is still very high.

There is another type of nail that is rarely seen but very typical, which is inverse nail, also called spoon-shaped nail. The entire nail is concave in the middle and the edges are raised. It is so concave that it can hold a drop of water. I met an older brother at a construction site who ate instant noodles all year round. When he came here, all ten of his fingernails were spoon-shaped. It was found that he had severe iron deficiency anemia. After taking iron supplements for three months, the nails slowly grew back. Of course, not all inflamed nails are anemic. Many housekeepers and hairdressers who have been exposed to detergents and disinfectants for a long time will also suffer from temporary inflamed nails due to long-term corrosion of their nails. If you change your working habit of wearing gloves, you can slowly recover.

Many people think it's anemia when they see white nail beds. In fact, it's not necessarily true. If you freeze outside for half an hour in winter, your nail beds will turn white. If you warm up and turn pink immediately, it's completely fine. If the nail bed is pale all year round, and it takes two or three seconds for blood to return after pressing, and the lips and lower eyelids are also white, it is most likely anemia. If the fingertips are also accompanied by coldness and numbness all year round, it is best to check the peripheral circulation. Many peripheral neuropathy in the early stages of diabetes will also have pale nail beds and numb fingertips.

Let’s talk about nail discoloration and layering. Many people think it’s onychomycosis when they see their nails turn yellow and gray. They buy antifungal medicines and apply them on their own, but they don’t work for more than half a year before they come to the hospital. I once had a patient who had been taking anti-tuberculosis drugs for a long time, and her nails turned yellow, which was not a fungal infection at all. There was also a little girl who had manicures for half a year. She did not remove her nails and just polished off the surface and applied new ones every time. Her nails turned yellow like old tree bark. She stopped doing manicures for two months and was fine. Only when the nail discoloration is accompanied by thickening, scum removal, and a hollow area under the nail, it is most likely to be a fungal infection, that is, onychomycosis. This kind of disease can only be confirmed by a fungal microscopy. Don't injure the nail bed by using medicine indiscriminately.

When it comes to nail problems, we cannot avoid the most feared black line under the nail. Many people think that they are going to get melanoma when they have a black line. They are so scared that they can't fall asleep after scrolling through their mobile phones all night. It’s really unnecessary. Most of the subungual black lines are onychomycosis, just like someone drew a straight black line under your nail. As long as the long-term width of this line does not exceed 3mm, the color is uniform, the edges are neat, and there is no sudden widening or the periungual skin turns black, don’t worry about it. If there are sudden changes like the ones just mentioned, go to the dermatology department for dozens of dermoscopy checks. The current consensus in the academic community is that when the subungual black line suddenly widens more than 5 mm without any trigger, the boundary is blurred, and it is accompanied by nail bed ulceration, you need to be highly vigilant about the possibility of melanoma.

Finally, let’s talk about a common problem that everyone often encounters, which is the inexplicable redness, swelling and pain around the nail. Many people think it is paronychia. Just cut the ingrown nail and apply povidone iodine and it will be cured. However, if it grows repeatedly and becomes swollen again within two weeks of recovery, accompanied by small pits on the nail surface and skin peeling on the fingers, it is best to check whether it is periungual inflammation caused by psoriasis or eczema. I once had a patient who suffered from recurring paronychia for half a year. He cut his ingrown toenail until it bled several times. In the end, he was diagnosed with psoriasis. Early detection and early intervention can control it well.

In fact, having said all this, you don’t need to stare at your nails every day. Many people have vertical lines and small crescents on their nails, which are due to natural or normal metabolic fluctuations. If they really have organic problems, most of them will be accompanied by other physical symptoms. Don’t scare yourself. If you are really unsure, go to the dermatology department for a consultation. It costs more than ten yuan, which is much more reliable than searching online for a long time and wondering.