The common belief is that the nails mirror the state of the body’s organs. In fact, this seems to have been accepted as a medical fact by most people for hundreds of years. Some doctors and scientist reject these claims and disprove this theory while others believe it wholeheartedly and base their diagnosis and treatment on this philosophy (for example: Chinese medicine).
When did “nail diagnosis” begin?
The idea began in Ancient Greece when Hippocrates suggested that bodily imbalances were reflected on the fingernails. He believed that each nail corresponded with an organ in the body such as the kidneys, lungs, or liver. Ancient China took things one step further when they stated every small change within your nails was linked with an illness elsewhere in your body.
Every culture has its own unique take on the connection between your nails and your health. For example: in ancient Egypt, a long nail indicated good health while short nails meant illness was imminent; in India, yellow or brown nail color means liver disease is present; and in Taiwan, horizontal lines that fork at the end of the nail mean asthma.

Is there real science behind “nail diagnosis”?
It turns out these associations aren’t as crazy as they might sound. As modern medicine has developed, it’s become clear that some kind of link does indeed exist. Let’s explore this subject further…
It’s interesting to note that doctors in ancient times would only prescribe leeches if the patient saw any black spots on their fingernails. Modern-day physicians no longer use this method but it does seem plausible that what you see on your nails reflects what’s going on inside your body. After all, nails have been examined by doctors for signs of infections or scarring due to trauma so why wouldn’t it work with illnesses?
Studies have shown a possible correlation between certain health issues or illnesses and what you see on your nails. For example: horizontal lines, white spots, brownish staining, grooves/ridges, broken nails, clubbed nails (and onycholysis) which are all strong indicators of health issues elsewhere in your body.
Vertical nail ridges might indicate lung disease while spoon-shaped nails could indicate anemia. The presence of white spots may be an indication of low zinc levels. Liver disease is often accompanied by yellow-brown discoloration of the entire nail or just the lunula. Vertical ridges that turn into koilonychia (spoon-shaped nails) may be a symptom of psoriasis. Horizontal lines accompanied with brittleness or breaking nails might indicate lung disease, while vertical lines accompanied by white spots might indicate heart disease. Clubbing of the nails, which is often seen in patients with respiratory diseases, significantly increases the risk of cancer.
Chronic kidney disease can cause spoon-shaped, pitted, or curved nails that are brownish or yellow-brown discolored on at least one-third to three-quarters of the nail. Pulmonary hypertension causes clubbing on more than half of affected nails where they are also smooth and pale pink. Repeated trauma can lead to longitudinal ridges of which there are five degrees based on how deep the ridges go into the nail bed.
The only correlation that seems to have some scientific evidence behind it is vertical ridges which can be an indicator of lung disease. The medical literature suggests that the most common cause of vertical ridges is benign respiratory diseases such as asthma, emphysema, and chronic bronchitis.
When you look at your nails for signs of illness, you need to consider several factors: What do they normally look like? How many changes have there been in them? How long has this change persisted for? Was there any specific incident that caused the problem (for example; infection, trauma, or reaction to medication)? Here are some differences between healthy nails and other conditions:

Healthy Nails
- Oval shape with a white crescent near the cuticle called lunula
- Broadly attached to underlying tissues resulting in blood flow within the nail
- No visible specks on the nails
- Oval and symmetrical shape
- Brittle with longitudinal ridges that don’t reach into the center of the nail bed (if they do, it could be a melanoma)
Osteoporosis
- Thinner nails and brittle with horizontal ridges (not to be confused with Beau’s lines which indicate temporary illness)
Cancer
- White spots caused by keratin debris due to an interruption in blood flow within the nail; this is more common if the cancer is present in bones such as breast cancer, lung cancer, or leukemia. Other symptoms can include thinned-out nails and pain.
Liver disease
- Reddish-yellow discoloration accompanied by vertical ridges which may not go all the way to the cuticle.

Diabetes
- Smoother nails with longitudinal ridges that reach into the center of the nail bed (may also be koilonychia but this is more common in patients with psoriasis).
Psoriasis:
- Vertical lines accompanied by spooning of the nails; caused by stiffening of connective tissues within upper dermis. Also, can cause diffuse redness in some parts along with pitting, thickening, shedding and separation of nails from underlying tissue.
Pachyonychia congenita
- Inflammation of the pulp due to abnormal keratinization which is accompanied by abnormally thick, hard nails.
What are the signs of cancer?
Doctors have been aware of a possible association between certain diseases and abnormalities within our nails for many years. However, only recently have studies been carried out to investigate this link more thoroughly. One recent study looked at over 100 patients and their nails and found that cancerous cells were present within 1 or more of the 37 test subjects.
This is a fascinating discovery as it provides doctors with another way to diagnose these very challenging diseases. The study was published in the International Journal of Dermatology.

How can the nails help distinguish between types of cancer?
To understand how this works, we need to look into skin diseases such as psoriasis, melanoma and lichen planus (a chronic pruritic papulovesicular dermatitis). People suffering from these can often have nail changes too including: yellow lines creeping across your nails; white streaks running down them; and pitting – small dents all over the surface of your fingernails.
Doctors are now aware of this link, which helps them to distinguish between different types of cancer within an early stage. This is important because the sooner you treat the disease, the higher your chances of survival will be. I recommend that you visit a dermatologist if any of these symptoms appear.
Conclusion
I hope that was helpful and provided you with some interesting insights into how our nails can reflect what’s going on inside our bodies. In order to keep yourself healthy, doctors recommend eating a healthy diet rich in vitamins and minerals, exercising regularly and maintaining a positive mental attitude!
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