What Do Your Nails Say About Your Health?

Farzollah Gholizadeh and Fariba Bayrami

Signs you shouldn’t ignore

Have you ever looked carefully at your nails for a few seconds before cutting them?

What colour are they? Smooth, or ridged? Strong, or do they break easily? How much of the white moon (lunula) at the base can you see? Do your nails grow fast or slowly? Has a spot, pit or change in colour appeared that wasn’t there before?

Nails are not just part of how our hands and feet look. They are slow-growing tissues, and so they can sometimes carry the trace of the body’s state weeks or even months earlier.

In Sina–Unani medicine and other schools of traditional medicine, observing the body’s outer appearance has been one of the important tools for understanding a person’s inner state. The colour, texture, shape and quality of the nails were considered together with the skin, tongue, hair, eyes, pulse and other signs.

Today’s medicine also takes nail changes into account in many skin diseases and in some general disorders of the body.

But the important point is this:

The nail doesn’t diagnose disease on its own; the nail gives clues.

The art of diagnosis is understanding these clues and assessing them together with the body’s other signs.

Why can the nail give information about the body?

The nail plate is made largely of keratin and grows from the nail matrix (the nail root).

Normal nail growth depends on many factors, including:

• Sufficient, balanced nutrition
• Blood circulation
• Oxygenation
• The health of the tissues around the nail
• The body’s general condition
• Age
• Hormones
• Diseases
• Medicines
• Environmental and chemical factors

So changes in the body’s condition can sometimes show in the nail’s colour, growth rate, thickness, strength or shape.

The nail is not like a blood test that gives a precise, numerical result; it is more like a slow-moving logbook that records some of the body’s changes over time.

What does a healthy nail usually look like?

A healthy nail usually has a relatively smooth surface, a suitable texture and a colour that matches the natural colour of the skin and nail bed.

It shouldn’t be overly brittle, constantly peel in layers or separate from its bed for no reason.

Of course, the shape and thickness of the nail, and even how much of the moon (lunula) shows, vary from person to person.

That is why there is a very important principle in the science of signs:

Change compared with the person’s own normal state is often more important than comparing their nails with other people’s.

If someone has had nails of a particular shape for years, that feature is not necessarily a sign of illness. But if the same nail changes clearly within a few months, it becomes worth looking into in more detail.

The first thing the nail shows us: colour

One of the first steps in observing the nail is looking at its colour.

The nail can look whiter, paler, yellow, blue or purple compared with before, it can darken, or coloured lines and spots can appear on it.

Each of these changes can have many causes.

For example, marked paleness of the nail bed can, together with other signs, sometimes draw our attention to the state of the blood.

Yellowing of the nail can have different causes, from dyes and external substances to fungal infection and some diseases.

An unusual blue or purple colour of the nails can draw attention to oxygenation and blood circulation.

But none of these colours on its own is a definitive diagnosis.

Colour is the beginning of the questioning, not the end of the diagnosis.

White spots: not always calcium deficiency

One of the most common beliefs is that every white spot on the nail means calcium deficiency.

This interpretation is oversimplified.

White spots can appear after small knocks to the area where the nail forms, and they can have other causes too.

The type, number and location of the spots, whether they recur, whether there are other changes in the nail and the person’s general condition all matter.

A more thorough assessment also looks at nutritional status, the absorption of nutrients and some micronutrients; but a deficiency of a particular substance cannot be diagnosed just by looking at a white dot.

What do brittle nails tell us?

Brittle nails are one of the most common complaints.

Sometimes the cause is very simple:

Frequent contact with water, detergents, solvents and cleaners such as nail polish and acetone, frequent manicures, knocks or a dry environment.

But if the brittleness is severe and persistent, we need to look at a bigger picture.

Nutritional status, iron and other nutrients, thyroid problems, skin diseases and the person’s general condition may be considered in the assessment.

From the point of view of traditional medicine too, the quality and strength of the nail, together with other signs, matter in assessing the quality of the tissues’ nourishment and the body’s moisture–dryness balance.

Nail ridges: lines that sometimes record the body’s history

Especially with age, some lengthwise lines can be normal.

But not all ridges are the same.

Sometimes clear crosswise lines appear on several nails. Changes like these can show that the nail’s normal growth was disrupted for a time.

This disruption may have followed a serious illness, a fever, marked physical stress or other conditions.

Interestingly, because the nail grows slowly, the position of the line on the nail can sometimes give a specialist a clue as to roughly when the disruption happened.

So the nail sometimes carries part of the body’s past on it.

Small pits in the nail

Sometimes the nail surface looks like a surface with many tiny dots pressed into it.

This can be seen in some skin diseases and inflammatory diseases.

What matters is this: in a proper assessment of signs, we don’t look only at the pit itself; the skin, hair, joints, the number of nails affected and other signs should also be examined.

A single sign usually carries limited meaning.

When the nail changes shape

Sometimes the problem is not only colour or brittleness; the overall shape of the nail changes.

The nail can become overly domed, hollow like a spoon, thickened, separated from its bed, or its curve can change markedly compared with before.

These changes matter more especially when:

they are new, they affect more than one nail at the same time, or they come with other general signs.

Some changes in nail shape can draw the practitioner’s attention to the state of the blood, lungs, heart, thyroid or nutrition, or to skin diseases.

But exactly at this point, simple observation must give way to interpreting patterns.

The nail and anaemia

Some nail changes, together with other signs, can lead us to examine iron and the state of the blood.

For example, if a change in nail shape or brittleness comes with pallor, tiredness, weakness, dizziness, palpitations or a reduced capacity for exertion, investigating anaemia becomes more important.

What matters is this: anaemia is not diagnosed by looking at the nail; the nail can only be one of the clues.

The nail and the thyroid

Thyroid disorders can also affect the skin, hair and nails.

A change in growth rate, brittleness, a change in nail quality or separation of the nail from its bed can in some cases be seen together with thyroid disorders.

If nail changes appear in the same period as changes in weight, tolerance of cold or heat, heartbeat, energy, sweating, skin and hair, examining them becomes even more worthwhile.

Again the same principle repeats:

The nail should be read with the body, not apart from it.

The nail and diabetes

In people with diabetes, many factors can affect the nails and the surrounding tissue.

Changes in peripheral blood circulation, a greater tendency to some infections and impaired tissue repair are among the factors that make nail care, especially toenail care, more important.

In a person with diabetes, a change in nail colour, thickening, fungal infection or damage around the nail should be examined more carefully.

The nail, liver and kidneys

Some systemic diseases can also cause changes in the nail’s appearance.

Particular patterns of colour or appearance change have been reported in some liver and kidney diseases.

But these signs gain real value when they come with a change in skin and eye colour, swelling, itching, changes in urine, general weakness or other signs.

So seeing a differently coloured nail never means a diagnosis of liver or kidney disease.

The nail, heart and lungs

Some important changes in nail colour and shape can draw attention to oxygenation, the heart and the lungs.

For example, a newly starting blue or purple colour of the nail bed, or a marked, gradual change in the shape of the fingertips and nails, is not something that can be explained by temperament alone.

Medical assessment is important, especially if it comes with shortness of breath, weakness or a reduced capacity for exertion.

The nail, digestive system and absorption of nutrients

One of the important principles of Sina–Unani medicine is that the quality of the body’s tissues depends largely on the quality of digestion and nutrition.

The nail is no exception to this rule.

If the digestive system cannot digest and absorb nutrients properly, the skin, hair and nails can be affected over time.

In today’s medicine too, some digestive disorders and absorption problems can occur together with deficiencies of iron, zinc, vitamins or other nutrients, and can indirectly affect the nail.

So to understand the cause of a nail change, we sometimes need to take the question beyond the nail:

How is digestion? How is appetite? How are the bowels? Are there signs of weight loss or poor absorption?

The nail’s growth rate is a sign too

Nails grow at a certain rate, but this rate is not the same for everyone.

Age, season, nutritional status, general health, diseases and many other factors affect it.

So a slowing or marked change in nail growth, especially together with other changes in the body, can be part of a bigger picture.

Sometimes what matters is not whether growth is “slow or fast”, but change compared with the usual growth rate of the person’s own nails.

What does the white moon at the base of the nail tell us?

The light, crescent-shaped area at the base of some nails, called the lunula or nail moon, is a natural part of the nail’s structure.

Its size and how much of it shows vary from person to person, and even between the fingers of the same person.

So whether the moon is small or large should not on its own be used to diagnose illness.

But in the traditional science of signs, the moon, the colour of the nail bed, the quality of growth and the nail’s other features are observed together.

Its diagnostic value increases when several consistent changes are present at the same time.

Can temperament also be looked for in the quality of the nail?

In Sina–Unani medicine, the diagnosis of temperament never rests on a single organ.

Even so, the quality of the nail can be part of the whole set of signs.

In general, more dryness, brittleness and roughness, together with other signs, can point to increased dryness in the body.

On the other hand, the quality of the tissue, growth, colour and the state of the nail bed should be assessed together with the skin, hair, body build, body temperature, sleep, digestion, pulse and other signs.

So you cannot say that a person is definitely Demevi, Safravi, Balgami or Sevdavi just by looking at their nails.

Diagnosing temperament is diagnosing a pattern, not a sign.

Which matters more, fingernails or toenails?

Both matter, but their conditions differ.

Toenails are affected more by shoes, pressure, knocks, moisture and fungal infection.

Fingernails are exposed more to water, detergents, chemicals, manicures, nail polish, gel and everyday damage.

So before linking any nail change to an internal disease, local factors must be ruled out.

Has one nail changed, or all of them?

This is a very important question.

If only one nail has changed, local factors such as a knock, infection or damage become more likely.

If more than one nail at the same time shows a similar change, paying attention to the body’s general factors becomes more important.

This rule is not absolute, but it is one of the simplest principles for starting to observe the nail properly.

A new change matters more than an old feature

Suppose a person has had thin nails since childhood.

That is not the same as someone who has always had strong nails and whose nails have become thin and brittle in the last six months.

In the science of signs, the important question is always:

What has changed compared with the past?

Sometimes this one question is worth more than dozens of scattered observations.

Which changes should not be ignored?

It is better to have some nail changes examined, especially when they are new, persistent or progressive:

• A sudden, marked change in nail colour
• Nails turning blue or purple
• A new, changing dark line on one nail
• A marked change in nail shape
• The nail separating from its bed for no clear reason
• Excessive thickening
• Inflammation, pain or pus around the nail
• More than one nail changing at the same time
• Slow healing of wounds around the nail, especially in people with diabetes

In particular, a new and changing brown or black band on a nail should not be put down only to temperament, a knock or a nutritional deficiency; it should be assessed by a doctor, preferably a dermatologist.

Five simple questions for reading the nail

When you notice a change in your nail, ask these before drawing any conclusion:

• Has the nail’s colour changed compared with before?
• Has its shape or thickness changed?
• Is one nail affected, or several?
• Did the change appear suddenly, or gradually?
• In the same period, was there also a change in the skin, hair, energy, weight, breathing, digestion or other parts of the body?

These five questions can turn a simple observation into a more careful clinical view.

Don’t read the nail apart from the body

One of the biggest mistakes in the science of signs is assigning a particular disease to every nail change.

For example:

“This spot means a deficiency of such-and-such vitamin.” “This line means the liver.” “This colour means the kidneys.”

The body doesn’t work that simply.

One sign can have several causes, and one disease can cause many different signs.

So in clinical diagnosis the nail should be assessed together with the skin, hair, tongue, lips, eyes, pulse, sleep, appetite, digestion, elimination, sweating, body temperature and the person’s general condition.

This is where the difference between seeing a sign and understanding a sign appears.

Conclusion: nails are silent, but not without messages

We look at our hands every day, but we rarely think that the nails also record part of our body’s history.

The colour, shape, surface, thickness, strength, growth rate, moon, lines and changes of the nail can give us clues about the state of the skin and tissues, nutrition, the blood, circulation, oxygenation, hormones and some internal diseases.

But the most important principle is:

Don’t diagnose a disease by looking at a single sign.

The nail won’t tell you “You have this disease”.

The nail says:

“Something has changed here; look more carefully.”

In the science of signs, this “looking more carefully” is the beginning of diagnosis.

When the nail is read together with the skin, tongue, hair, lips, eyes, pulse, secretions, digestion, sleep and the body’s other signs, a much more complete picture emerges.

Many people look at their body every day, but far fewer know the body’s language of signs.

Getting to know this language is too wide a subject for all its details to be covered in one article. Types of lines, colours, spots, changes in shape, the relationship between several signs and how to tell simple changes apart from important ones are each subjects of their own.

The aim of this article was only to open a window:

The body sometimes speaks through signs before it speaks through pain.

And the nails are one of the places worth learning to read in this conversation.

For further reading

Detailed subjects such as the science of signs of the nails, skin, tongue, lips, hair, eyes and the body’s other outward signs, and how to assess them together in diagnosis, are covered more fully and step by step in Dr Kalan’s “Elaim & Delail” book and course (currently in Turkish).

Curious about your own baseline? Take the free temperament test.

References

• Ibn Sina. Al-Qanun fi al-Tibb; sections on temperament, the humours, evidence and the body’s signs.
• Al-Razi, Muhammad ibn Zakariya. Al-Hawi fi al-Tibb.
• Jurjani, Sayyid Ismail. Dhakhira-yi Khwarazmshahi.
• Aqili Khorasani, Muhammad Husayn. Khulasat al-Hikma.
• Wollina U, Nenoff P, Haroske G, Haenssle HA. The Diagnosis and Treatment of Nail Disorders. Deutsches Ärzteblatt International. 2016.
• Singal A, Arora R. Nail as a window of systemic diseases. Indian Dermatology Online Journal. 2015.
• Tully AS, Trayes KP, Studdiford JS. Evaluation of Nail Abnormalities. American Family Physician. 2012.
• Lipner SR, Scher RK. Evaluation of nail lines: Color and shape hold clues. Cleveland Clinic Journal of Medicine. 2016.
• Dr Kalan scientific and educational sources on the science of signs, temperament and traditional medicine.