These colours indicate illnesses

What do fingernails reveal about your health?

Fingernails are small mirrors of our health. They can provide important clues about our wellbeing. Fine longitudinal ridges, for example, are often harmless and a normal sign of ageing. However, they can also occur with certain conditions such as rheumatoid arthritis or liver problems.

Transverse ridges, also known as horizontal lines, often appear after recovering from illnesses like severe infections or extreme stress and are in a way the „Protokoll" of recent health challenges.

Brittle or soft nails often point to a nutrient deficiency. If nails repeatedly break or split, a vitamin deficiency or an underactive thyroid may be present. External factors such as frequent hand washing or contact with cleaning agents can also weaken nail structure.

Thin, soft nails can also indicate a lack of important vitamins and minerals such as iron, calcium or biotin.

Nail discolouration should not be ignored. Yellowish discolouration is usually harmless, while light brown tones can indicate a fungal or bacterial infection. Dark discolouration can be a sign of skin cancer and should be examined immediately.

The cuticle can also give insight into health. If it constantly splits, this can be due to excessive hand washing or insufficient care. A deficiency in vitamins, particularly iron and vitamin D, may also be the cause.

Why do white spots appear on nails?

White spots on nails are a common phenomenon often mistakenly linked to a deficiency of nutrients like calcium, protein or vitamins. This is a myth. In fact, these spots, medically called leukonychia punctata, result from damage to the nail matrix.

The nail root, known as the lunula, can be damaged by various influences. An over‑aggressive manicure, where the cuticle is pushed back or removed vigorously, can cause them, as can minor knocks to the nails. These spots are particularly common in people who bite their nails, or on the right hand of right‑handed people and the left hand of left‑handed people.

If the nail root is injured, the keratin layers of the nail do not grow together properly and small cavities form. These cavities fill with air and appear as white lines on the nail.

Fortunately these spots are harmless and disappear on their own once the nail has grown out. With some patience the affected areas can simply be filed or trimmed away.

Why do nails turn green?

Green discolouration of the nails, also called „greenies", is often a common sign of infection with Pseudomonas bacteria. These bacteria thrive in moist environments and produce greenish pigments such as pyocyanin and pyoverdin that deposit on the nail plate. The structure of the nail plate can be affected by the constant presence of the bacteria, which makes the discolouration appear more intense.

These infections are generally not painful and often affect only one or two nails. The colour can range from greenish to bluish or yellowish. If the infection is not treated, bacteria may spread and alter the structure and shape of the nail. In the worst case the nail can even detach from the nail bed.

The main cause of these green stains is often small injuries to the nails or cuticle that allow bacteria to enter. A weakened natural barrier of the nails also makes them more susceptible to such infections.

People who wear artificial nails are particularly prone to this. If the artificial nails are not applied correctly, moisture can collect between the artificial and the natural nail, creating an ideal environment for bacterial growth.

Why do nails turn yellow?

Yellow discolouration of the fingernails can have various causes and should not be ignored, as it often indicates health problems. Similar symptoms may also affect toenails, worsened by poor hygiene or tight shoes.

A common cause of yellow nails is nail fungus. This is caused by fungi that invade the nail and initially cause it to lose its natural shine. Over time the nail becomes thick, brittle and may even detach from the nail bed. If left untreated this can become painful and lead to complete loss of the nail.

Another possible issue is the rare yellow nail syndrome, in which nails turn yellow and become thick, cracked and slow‑growing. This syndrome is often associated with respiratory problems or fluid retention in the body.

Yellow nails can also be due to external factors, such as frequent application of coloured nail polish without a protective base coat, which allows pigment to penetrate the nail. Smoking can also cause this, as nicotine deposits on the nails.

Occasionally yellow fingernails can indicate a vitamin E deficiency caused by an unbalanced diet. In rarer cases a liver disease can cause yellow nails, often accompanied by yellowing of the skin and the whites of the eyes.

In some cases certain medications or chemical substances in hand creams and nail care products can also discolour nails. The pigment beta‑carotene, found in vegetables such as carrots, can also cause a temporary yellow tint with frequent contact that washes off with hand washing.

What does a black spot on the nail mean?

A black spot on the nail can mean different things depending on its cause. If the spot appears after a blow or injury, such as a jammed finger, it is usually a harmless bruise. This occurs when blood vessels under the nail are damaged. The blue or black discolouration often increases immediately after the injury but fades over time and eventually disappears on its own.

However, caution is advised if a dark spot occurs for no apparent reason and persists for a long time. In that case you should see a dermatologist to clarify whether it might be a melanoma, a particularly dangerous form of skin cancer. Any unexplained black spot or ridge on the nail should be taken seriously and medically assessed.

Discoloured nails: when to see a doctor?

If your nails become permanently discoloured or change significantly, it is important to consult a doctor. Such changes can sometimes indicate serious health problems. For example, clubbed nails, often linked to heart or lung disease, usually appear late in the course of an illness, when other symptoms like breathing or heart problems are already present. Timely treatment by a specialist can help clarify the causes of nail discolouration and initiate appropriate measures.

Nail changes should not be taken lightly. Especially dark discolourations under the nail require caution, as they can indicate a melanoma, i.e. skin cancer. Yellowish or brownish discolourations can also be a warning sign, as they are often caused by fungal infections that should be treated promptly.

With unusual nail changes it is advisable to consult a dermatologist early in order to detect and treat possible serious conditions in good time.

Nail discolouration: how to prevent and treat effectively

• Always use a base coat before applying coloured nail polish. This protects your nails from pigment penetration that can cause discolouration.
• When using cleaning agents, always wear rubber gloves. These protect not only your skin but also your nails from aggressive chemicals that can cause staining.
• If your nails are already discoloured, you can brighten them with lemon juice. Simply rub half a lemon directly over your nails or soak them in a mixture of lemon juice and water.
• A scrub can help with mild discolouration. Mix olive oil with coarse sugar and gently massage the mixture into your nails.
• Apple cider vinegar is another effective home remedy against nail discolouration. Mix a tablespoon of apple cider vinegar with lukewarm water and soak your nails for a few minutes.
• Use baking soda to remove stains naturally. Dissolve a packet of baking soda in warm water and soak your nails for about five minutes.
• Avoid smoking to prevent yellowish nail discolouration. Nicotine can deposit on nails and leave unsightly stains.
• Maintain a balanced diet to avoid nutrient deficiencies that can lead to discolouration. Vitamin E‑rich foods such as nuts and salmon are particularly helpful.
• If your nails are discoloured due to a fungal infection, use antifungal creams or polishes to treat the infection.
• Be cautious with hand creams and nail polishes that contain silver nitrate. This substance can turn your nails yellow.
• Use special polishes with light‑reflecting agents that can mask and simultaneously treat discolouration.
• To protect your nails from staining you can also rely on natural oils such as jojoba or almond oil, which strengthen and nourish your nails.
• For stubborn discolouration that does not respond to home remedies or care products, do not hesitate to consult a dermatologist or nail specialist.

Nail discolourations can be a sign of various health problems or external influences and should not be ignored. With proper care, a balanced diet and sensible use of home remedies, many discolourations can be treated or even prevented effectively. However, for persistent or unexplained changes it is important to seek medical advice in good time to rule out serious causes.