What Causes Brittle Toenails with Ridges?

The status of our health can be determined by our nails. Strong and durable toenails indicate physiological wellbeing. On the other hand, brittle and ridged nails indicate systemic disease, nail injury or poor underlying health. In some cases, ridged nails may have no discernible cause.

Given the number of risk factors, it can be difficult to determine the reason for nail abnormalities. However, studying the type, color and location of the ridges can narrow down the list of causes.

We’ll explore the various causes of toenail ridges and brittle nails so that you can determine what is wrong. We’ll then look at whether it’s possible to get rid of toenail ridges for good.

Why Do I Have Ridges on My Toenails?

5-10% of American’s develop ridges on their nails, so it’s a common toenail condition. Brittle toenails are typically a precursor to developing ridges.

The known risk factors for developing toenail ridges include:

Vitamin or Mineral Deficiencies
Aging
Trauma or Injury to the Nail
Over Washing or Excessive use of Nail Polish
Kidney Disease
Genetics (vertical nail ridges can be inherited and may develop in early childhood)
Autoimmune Disorders (i.e., Rheumatoid Arthritis, Thyroid Conditions)
Medication Side Effects
Fungal Toenail Infections
Diabetes
Suddenly Becoming Unwell – Heart attack, Stroke, Pneumonia, etc.
Nail Psoriasis or Eczema
Chemotherapy
Chronic or Extreme Stress

Multiple factors often interact to cause toenail ridges to develop. For example, a chronically stressed individual who injures their toenails during sports is likely to lead to brittle toenails with ridges. This is because chronic stress slows down the body’s natural healing process.

Psoriasis and eczema might not necessarily cause ridges in and of themselves, but if people with these conditions regularly get their nails wet, the imbalance of moisture can aggravate psoriasis or eczema, which can lead to ridges developing on the nails.

When trying to determine the cause of toenail ridges, notice whether they appear towards the base or the tip of the nail. If the ridges begin right at the base of the toenail, this would indicate that the damage has been caused recently.

If the ridges are localized towards the tip of the nail, this might suggest that the cause happened in the recent past, because nail growth has occurred since that time.

Remember, toenails grow at a slow rate of approximately 0.05mm per day, so it can take six months to grow out any nail damage. This means that toenail ridges could indicate an ongoing health concern or one that occurred as many as six months ago.

You might still be feeling bemused by the number of potential causes for ridged nails. Studying the direction and texture of the ridges will make the deciphering process a lot easier. We’ll start by defining the differences between horizontal ridges, vertical ridges, and concave nails with ridges.

What Causes Horizontal Ridges on the Nails?

Horizontal ridges on the nail are a more significant concern than vertical ridges. There are four categories of horizontal ridges – Beau’s Lines, Mee’s Lines, Muehrcke’s Lines, and Lindsay’s Lines.

It’s important to distinguish each type of horizontal line because they indicate different causes.

1) Beau’s Lines

Beau’s lines are depressed ridges than run horizontally across the nail. They run parallel to the whites of the nails, but they are not necessarily neat or uniform ridges. There may be peaks and troughs within the ‘lines.’

If you have Beau’s lines in your nails, you’ll be able to feel a depression in the nail where the line is. This is not the case with Mee’s Lines, Muehrcke’s Lines, and Lindsay’s Lines.

Beau’s Lines may be caused by one of the following factors:

Chemotherapy – Chemotherapy is invasive and dehydrating for the nail and can cause many nail changes – including Beau’s lines. Scientists discovered that by measuring the distance between the lines, it’s possible to determine when a patient’s last chemotherapy session took place. The rate of nail growth slows down in cancer patients, so their ridges or ‘Beau’s lines’ may persist for longer than six months.

Beau’s lines caused by chemotherapy look like the output of a pulse monitor – the edges are jagged, and there are lots of peaks and troughs in the lines.

Stressful Experiences – This is likely due to the intense physiological changes that occur during periods of high stress.
Severe Physiological Events or Infections – Pneumonia and heart attacks are both known causes of Beau’s lines in the nails.
Rheumatoid Arthritis – Several studies have shown that sufferers are more likely to develop Beau’s lines when their condition flares up.
High Fever/Chills – Fever can cause Beau’s lines to occur in the nails. Once the person has returned to good health, the nail should grow at a normal rate, and they should grow out.
Diving – Studies have shown that divers are more susceptible to developing this type of nail ridge. Scientists aren’t sure why Beau’s lines occur in divers, but it’s likely to be due to the stressful physiological effects of immersion and pressure.
Zinc Deficiency – Zinc is vital for strong nails, and many nail conditions involve a zinc deficiency. In cases where someone eats a healthy balanced diet, deficiency may still occur due to absorption problems.
Injury or Trauma to the Nail – Sports injuries or accidents can cause trauma to the nail, which may lead to Beau’s lines. If the lines are isolated to one or two nails, this indicates that the lines have been caused by injury rather than systemic illness.

Remain vigilant of the potential causes of Beau’s lines, but remember that toenail ridges don’t always point to an underlying health concern.

2) Mee’s Lines

Unlike Beau’s lines, Mee’s lines are not depressed into the nail. Instead, they are characterized by a horizontal line of pigmentation in the nail. The line appears white and does not disappear when pressure is put on the nail.

Mee’s lines are typically caused by:

Arsenic Exposure or Thallium Exposure
Renal Failure – Kidney problems can cause various changes to the nails, including Mee’s lines, Muehrcke’s lines, and Lindsay’s lines. Renal failure causes inflammation and iron deficiency in the body, which is thought to have an impact on nail health.
Chemotherapy Treatment
Diabetes – Diabetes impairs circulation. The nail matrix needs a reliable blood supply to encourage healthy nail growth, so diabetes patients often develop these lines on their nails.
Trauma or Damage to the Nail – Mee’s lines on the toenails may be caused by dropping a heavy item of the feet.

3) Muehrcke’s Lines

These lines look similar to Mee’s lines, but they are situated on the nail bed rather than on the nail. When the nail grows, they will stay in the same place. Muehrcke’s lines are easily diagnosed because they disappear when pressure is placed on the nail.

Common causes include:

Chemotherapy Treatment – Studies have shown that Muehrcke’s Lines develop in patients being treated for Hodgkin’s Lymphoma. Treatment severely dehydrates the nail bed.
Sickle Cell Anemia – This is a severe form of anemia that is inherited. Iron deficiency anemia is linked to many nail conditions, though it is not thought to cause Muehrcke’s lines.
Renal Failure

4) Lindsay’s Lines

Lindsay’s lines are characterized by a horizontal brown band that covers the nail. Unlike Beau’s lines, the brown band is not indented into the nail – it is a band of pigmentation. The brown band usually covers half of the nail, and these bands are more common in fingernails than toenails.

Lindsay’s lines can indicate:

Renal disease
Hyperthyroidism – Hyperthyroidism is the reason behind many nail conditions, including Lindsay’s lines and Onycholysis. Onycholysis (Plummer’s nails) occurs when the nail separates from the nail bed. Hyperthyroidism is usually the cause of this condition. It’s essential to treat Onycholysis to prevent infection growing between the nail and the nail bed.
Heart Attack – These lines can occur after a heart attack, and may persist for many months
Smoke Stains – Lindsay’s lines on the fingernails can be caused by excessive smoking.

Having horizontal ridges doesn’t confirm one of these conditions. There may be alternative causes, or there may be no discernible cause. However, given that horizontal ridges can sometimes indicate a severe disease, it is vital to seek a medical diagnosis when they do arise.

What Causes Vertical Ridges on the Nails?

Onychorrhexis is the medical term given to brittle nails with vertical lines or ridges. They are less likely to indicate a severe illness. The risk factors include:

Aging – As we age, the moisture in our nails deteriorates.
Mechanical Causes – These include injury and trauma, but also over-washing and applying nail varnishes regularly.
Genetics – Studies have shown that vertical nail ridges may be an inherited trait. They may occur in the absence of brittle nails, so may not require treatment or intervention.

Although they rarely indicate illness, they may indicate the presence of psoriasis or eczema. People go for years without a flare-up of psoriasis, but then suddenly find their nails have become affected.

Psoriasis is an autoimmune condition which can cause patches of skin to become red, flaky and itchy. Some people who have psoriasis will develop ‘pitting’ down the middle of their nail. This will give the appearance of a long concave ‘ridge’ running vertically down the nail.

What Causes Concave Toenails?

Dry, brittle nails can sometimes develop into a condition called Koilonychia – or spooned nails. Rather than developing external ‘ridges,’ the toenail turns inwards, so that it sits like a spoon on the nail bed. The nail will also become whiter in color.

Concave toenails are almost always caused by iron deficiency. Chronic stress can amplify the effects of this deficiency by inhibiting proper absorption of iron and zinc from the diet.

If you want to determine whether you have this condition, try applying pressure to the nail. If the whiteness of the nail disappears under pressure, this may indicate Koilonychia.

‘Clubbed nails’ are the opposite of concave nails, but they are mentioned here because they can indicate a severe heart condition.

Clubbed nails are oversized nails, that can cause the ends of the fingers or toes to appear swollen. They should always be presented to a doctor for a medical diagnosis.

Why Do I Have Dry and Brittle Nails?

Fragilitas Unguium (dry, brittle nails) is a condition experienced by most people. Brittle nails are typically a precursor for nail ‘ridges’ so it is useful to understand how and why nails become brittle.

A nail will be strong and healthy if its water content is about 18%. If the water content drops below 16%, the nail can become very brittle. There is a fine line between healthy, supple nails and brittle, dehydrated nails.

To prevent water loss from the nails, you should adhere to these recommendations:

Limit Excessive Hand Washing or Foot Bathing – Constantly making nails wet and then drying them again can lead to dehydrated, brittle nails. It’s common for people who have their hands in and out of the soapy water to develop brittle nails.
Limit the Use of Nail Varnish – The chemicals in nail polishes or varnishes are dehydrating.
Try to Modulate Temperature – Switching between very hot and cold environments can have an impact on the nails. If you are unable to modulate temperature, make sure you cover your fingernails and toenails to protect them against extreme weather conditions.

Brittle nails almost always have a discernible cause, though ridges on the nails can leave patients and podiatrists perplexed. We’ll continue to discuss the reasons for nail ridges in more depth.

1) Vitamin and Mineral Deficiency

Various vitamin and mineral deficiencies cause brittle nails and nail ridges. For example, iron deficiency anemia can cause brittle and concave nails.

Other signs of iron deficiency anemia include fatigue, pale skin, and cold extremities. Zinc deficiency, on the other hand, is associated with horizontal Beau’s lines on the nails

Mineral deficiencies are not necessarily caused by a poor diet – they may occur due to malabsorption. For example, consuming too much iron can interfere with proper zinc absorption.

So, supplementing with iron can (ironically) cause nail ridges to occur due to a zinc deficiency. It is vital to only supplement iron when this has been recommended by a doctor.

Eating a varied and balanced diet will expose your body to as many vitamins and minerals as possible, and good overall health is required for healthy nails.

Clinics in Dermatology Journal found that Biotin deficiency is often associated with ridged nails and that supplementing with Biotin significantly improves nail health.

Overdosing on Selenium supplements has been found to cause hair and nail damage – including ridges on the nails. Checking your intake of this supplement is vital when trying to decipher a cause for your brittle, ridged nails.

2) Injury or Trauma

Sustaining an injury is a common cause of brittle nails and nail ridges. This factor should always be eliminated before any other explanations are considered.

Work accidents or road traffic accidents can cause nail damage and ridges. For example, if something substantial is dropped on the foot, this may cause the toenail to snap in the middle.

Assuming the top part of the toenail doesn’t come away from the nail bed, a ‘ridge’ will be left down the middle of the nail. Over time, moisture and infection enter this ‘ridge’ and cause new problems.

Many athletes succumb to nail trauma at one point or another. Poorly fitting sports shoes are often the culprit as these shoes squash the toenails, causing them to bend and become brittle.

If chronic trauma occurs, this can damage the nail matrix. This may lead to white discoloration marks and ridges in the nails.

Picking and scratching at the nails can cause the appearance of nail ridges, particularly if it continues for a long period of time. This can also encourage infections to take hold, so it’s crucial to avoid skin and nail picking.

3) Kidney Disease

Kidney disease or renal failure is known to cause abnormalities in the nails, especially horizontal lines and ridges (Muehrcke’s lines, Mee’s lines, Lindsay’s lines).

Kidney disease is a severe condition with many intrusive symptoms. It is unlikely that ridged toenails would be the first sign of the disease. However, if you have developed ridges in your nails, and have experienced the following symptoms, it’s worth being aware of this condition.

Symptoms of kidney disease include:

Tiredness
Shortness of Breath
Blood in the Urine
Swollen Ankles and Feet

Even when people start treatment (i.e., lifestyle changes or dialysis), it can take months or years for ridges in the nails to go away.

4) Cancer Treatment

Cancer treatment is known to impact the skin, hair, and nails. It can also alter the moisture content of nails. It also temporarily halts the growth cycle, so it can take longer than six months to grow out the nail ridges caused by cancer treatment.

Individuals who have gone through cancer treatment will usually notice some of the following changes in their nails:

Nails may become dark yellow or brown
Ridges or bands appear on the nails, often horizontally
Nails may start to crack, and shards of the nail may flake off (particularly during sleep)
Some people lose part or all of their nails

5) Medications

Other forms of medication are known to cause changes in the nails. Unfortunately, some medication can cause the nail to become very dry and brittle.

The following medications are thought to cause ridges in toenails or fingernails:

Retinoids (often found in acne or skin care treatments)
Carbamazepine (or other anticonvulsant drugs)
Some Antibiotics (i.e., Cloxacillin)
Itraconazole
Lithium

If ridged nails are caused by medication, it doesn’t necessarily mean that brittle nails are inevitable. There are steps you can take to nourish the health of your nails, which may stop the nail from becoming dehydrated and brittle. These recommendations will be discussed in detail below.

6) Fungal Toenail Infections

Fungal toenails are caused by an overgrowth of yeast or fungi in the nail. The infection often causes the toenail to become brittle and break off in sections. When the toenail does grow back, it usually does so unevenly, so ‘ridges’ may develop in the nail.

Beau’s lines (indented horizontal ridges) are associated with fungal infections because fungi sometimes enter the ridges, and ‘takes hold.’

It is imperative for people with Beau’s lines to keep their foot clean and avoid exposing themselves to fungi. People with Beau’s lines on their toenails should never allow their toes to come into contact with communal areas (i.e., swimming pools, locker rooms, gyms).

Both fungal nail infections and brittle nails are exacerbated by excess moisture. It is important not to over wash the hands and feet, and always ensure they are dried thoroughly.

7) Aging Process

Nail ridges are most commonly experienced by older people and approximately 60% of people over the age of 70 will experience brittle nails. Older people are more likely to develop fungal nail infections due to reduced mobility and impaired immunity.

Circulation becomes impaired with age, so the nail matrix is no longer able to function as effectively. Moisture levels in the nail become dysregulated. At the same time, the rate of nail growth is significantly reduced, so nail ridges stick around for a lot longer than six months.

8) Psoriasis and Dry Nails with Ridges

Psoriasis is an autoimmune condition that affects the skin and nails. It can affect the nails in different ways. People with this condition tend to experience the following complaints:

Nail Pitting – small dents in the nail occur. Often these are concentrated in a vertical line down the middle of the nail, but they can occur anywhere on the nail.
Lines or Ridges – Ridges may occur horizontally or vertically across the nail
Itchy Sensations – Nail Psoriasis can cause the nail to feel itchy and inflamed
Nail Crumbling – The nail may become very brittle and crumbly
Thickening of Skin – This characteristic distinguishes nail psoriasis from other nail conditions such as fungal nail infections. The skin underneath the nail tends to thicken so that the nail almost moves away from the nail bed.

There are prescribed treatments available for psoriasis, though keeping the nail hydrated is also likely to prevent ridges and pits from occurring.

9) Chronic Stress and Brittle Nails

Conditions affecting the skin, hair, and nails often have a partly psychosomatic basis. This may be because people who are chronically stressed are less likely to take care of their bodies. It may also be because stress impacts the immune system and impairs its ability to fight disease.

Studies have also shown that nervously rubbing the nail can cause a ridge to develop. This most commonly occurs on the thumbnail, but it may occur on any of the nails.

Brittle, ridged nails can, in themselves, become a source of stress because many people feel ashamed or worried about them. However, it’s possible to regain control of this situation by accurately diagnosing a cause, and then determining an effective treatment plan.

How to Strengthen Brittle Nails

Brittle nails are caused by dehydration. To retain moisture in the nail plate, follow these steps:

Soak the nails in warm water for 10 minutes
Apply a rich moisturizer containing urea, vitamin E or lactic acid. Alternatively, a natural moisturizer could be mixed using Jojoba oil and Lavender essential oil
Wear cotton socks to encourage absorption and leave for a minimum of 2 hours
Take Biotin supplements
Limit the use of nail varnishes, or use organic, gentle formulations

Ideally, moisturizing should be performed daily to strengthen dry and brittle nails. A review by Tibb Institute found that moisturizing nails is an effective treatment for brittle nails. It often halts the development of ridges on the nails.

The causes of toenails with ridges may run a lot deeper than mechanical or external factors. Nonetheless, it is possible to encourage better nail health by preventing brittle nails, avoiding fungal nail infections, and treating nail injuries promptly.