6 surprising things your nails can tell you about your health

A hand with healthy fingernails

When people pay attention to more functionally important parts of the body like the liver, kidney, oral cavity or eyes, it becomes easy to forget seemingly less essential parts like the nails. 

Always check your fingernails; they might be telling you something you don’t know about the state of your health.

The nails are made up of a protein called keratin. They grow from underneath the cuticles. As new nail cells are formed, the older ones become hardened and eventually get pushed out towards the tips of the fingers.

Fingernails grow slowly, and for that reason, they can give clues about what is happening in the body. 

How to know a healthy nail

You might be wondering how you would know when your nails are healthy. Healthy nails are usually smooth and pinkish in colour. However, there can be variations in nails.

Nail variations can result from the genes, meaning they are passed from parents to their offspring. You might notice your nails have a few faint ridges (strip-like) running through their length. Such ridges are usually harmless. However, a prominent, dark streak underneath the fingernails could signify melanoma. 

Other typical signs of healthy nails are:

  • Nails without many ridges
  • Sturdy nails that don’t easily break
  • Nails with cuticles
  • Nails with folds that are not puffy
  • Nails without dark streaks underneath
  • Nails that are free of pits and grooves

Photo by Andrik Langfield on Unsplash

Generally, people are born with different variations in nail shape and colour. However, if you notice something different or unusual about your nails, you shouldn’t ignore it because it may be telling you something you do not know about the state of your health. 

6 things your fingernails can tell you about your health

Below are things happening to your body that your nails can tell you about.

1. Kidney disease

As shocking as it might sound, sometimes, kidney disease is evident in patients’ nails. Several changes in nail shapes and texture can be a sign of kidney disease.

A 2016 study found that a phenomenon called Lindsay’s nails was found in about 40% of people with chronic kidney disease.

Lindsay’s nail is also called “half and half nail” and was named after the researcher who first documented their occurrence in chronic kidney disease patients in 1967. 

Lindsay’s nails are white near the cuticles, while about 20-60% remaining part of the nails close to the tips are reddish-brown. 

It is unclear why the colour change in nails happens to some people with kidney disease; however, it is suggested that it may result from a higher concentration of the beta-melanocyte stimulating hormone

Also, a distinct white streak, just as in psoriasis cases (will be discussed later), can point to chronic kidney disease. 

2. Liver disease

Another condition called Terry’s nail was also mentioned in the 2016 paper published in the Journal of General Internal Medicine.

In contrast to Lindsay’s nails, people with Terry’s nails have about 80% of their nail bed whitish in colour with the remaining 0.5-3mm band at the nail tip reddish, brownish or pinkish. 

According to the American Academy of Family Physicians, about 80% of people with liver cirrhosis have this distinctive nail colouring associated with Terry’s nails. It commonly affects fingernails but has been reported in toenails as well. 

A study published in the Indian Journal of Dermatology also stated that Terry’s nail could indicate chronic renal failure and congestive heart failure.

Terry’s nail is believed to occur when there are more connective tissues than normal in the nail bed and fewer blood vessels, thus causing the nails to appear white. 

3. Fungal infection

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Yellow spots or yellow colouration of the nails can be an indication of a fungal infection. Fungal nail infections are called onychomycosis and can cause thickening and discolouration of nails. 

Dermatophytes cause fungal nail infections. Dermatophytes are a type of fungi that require keratin to grow. 

Fungal infections may cause nail brittleness. Even though they are more common on toenails, they can also be found on fingernails.

Fungal nail infections usually develop over time and are not easy to cure. Cracks in surrounding skin can allow fungi to enter and cause nail infections. Fungal nail treatment often requires oral prescription antifungal medication.

4. Psoriasis

Psoriasis is a skin disease characterised by the appearance of red, itchy, scaly patches on parts of the skin like the elbows, knees, trunk and scalp. Psoriasis can also affect the fingernails and the toenails. 

Psoriasis typically causes a yellow-red discolouration on the nails. The discolouration is called “salmon patch” or “oil drop”. 

Other nail changes that can indicate psoriasis include:

  • Beau’s lines: Lines that run horizontally from one side of the nail to the other.
  • Indentations: Pits or nicks on the nail plate (the hard part of the nail that covers the fingertips)
  • White areas: Distinct white spots, also called leukonychia, may form on the nails.
  • Skin thickening and nail loosening: The skin under the nails may thicken, causing the nails to become loose and dislodge from their bed.

5. Moles or melanoma

Sometimes nail discolourations appear as lines that run vertically from the cuticles to the nail tips. This pigmentation of the nails can be a sign of benign moles or cancerous melanomas. 

There are cases where nail pigmentation are caused by genetic makeup or ethnicity. Asians and African-Americans have more tendency to experience normal nail pigmentation changes associated with ethnicity. 

A dark streak underneath the nails usually appears in individuals with acral lentiginous melanoma (ALM), a melanoma that occurs on the hands and feet. It occurs when the skin’s melanocytes become malignant. Malignant is another term for cancerous.

According to a study, ALM has a lower survival rate than other melanoma types.1 The big toe and thumbs are usually affected, and as cancer progresses, the affected nail may crack or break. 

6. Low oxygen levels

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Nails are located on the extremities, far away from the heart. This makes them a great indicator of low oxygen levels in the blood. 

The nail bed can turn purplish-blue when the fingers don’t get enough oxygen. The colour can be seen through the translucent nail. 

Lack of oxygen may be temporary due to situations like temperature changes. For instance, when the weather is cold, it can cause the contraction of blood vessels in the fingertips, thus preventing enough blood containing oxygen to reach the fingertips. 

However, a persistent blueish colouration of the nails can mean a more serious underlying health condition.

Note that not all nail colour, texture, or shape changes indicate serious health complications. But, for the sake of safety, it is often best to see a physician if you notice something unusual about your nails, as pointed out above.


  1. Bradford, Porcia T et al. (2009). Acral lentiginous melanoma: incidence and survival patterns in the United States, 1986-2005.
  2. Centres for Disease Control and Prevention. (2020). Fungal nail infections.
  3. Fawcett, Robert and Hart Thomas. (2004). Nail abnormalities: Clue to systemic disease.
  4. Pitukweerakul, Siwadon, and Sree Pilla. (2016). Terry’s Nails and Lindsay’s Nails: Two Nail Abnormalities in Chronic Systemic Diseases.
  5. Witkowska, Anna B et al. (2017). Terry’s Nails: A Sign of Systemic Disease.