Black Line on Nail, Thin Dark Line, On Thumb Nail, What It Means, Horizontal Black Line, Heart Problems, Vitamin Deficiency, Faint Black Line, Melanoma

Look at your nails. Do you see any black line on it? Continue reading on black line on nail, thin dark line, on thumb nail, what it means, horizontal black line, heart problems, vitamin deficiency, faint black line, and if it is melanoma

Thin Dark Line on Nail

A splinter hemorrhage is a bleeding that is under the nail. The discoloration caused by blood runs in the direction that the nail grows, not horizontally, thus creating the look of a splinter that is under the nail. Even color — usually a dark red-brown color — looks like the color of a wooden splinter.

Black line on Nail

Black line on Nail

The most common cause of this condition is trauma to capillaries that are under the nail. The little capillaries burst and clot, leaving a thin and black line on nail. Often when thinking of trauma to the nail, you can think of a type of blunt-force trauma, like the one emanating from hitting the nail using a hammer. But, the trauma which leads to a splinter hemorrhage might not hurt at all.

When a client comes in having a splinter hemorrhage, then the doctor’s first response is to assist the client recall the event that led to the trauma. Explain that the hemorrhage is likely due to bleeding and clotting that is from tiny capillaries which run under nails.

No treatment is required; in that the discoloration grows out with the nail. There’s no reason to get concerned if a patient doesn’t remember the exact event which led to the trauma. Most people won’t remember such details.

Even though trauma is the common cause of a splinter hemorrhage, but it’s not the only cause. The condition can also be brought about by fungal infections or even from eczema, though in both cases, there would likely be other symptoms beyond the appearance of the hemorrhage.

Most of the time a splinter hemorrhage will be harmless; however, there is the slight possibility that the condition can indicate a serious infection in lining of heart. If a patient can’t remember when the trauma happened, and she has any other conditions indicating heart problems, the doctor should recommend an evaluation of the nails.

It is unlikely that a client who has a splinter hemorrhage can suffer from endocarditis without other symptoms. But, the doctor should be aware of a possibility, in case a patient avoids other warning signs.

Thin Black Line on Thumb Nail

A narrow black line which forms vertically below your nail is known as a splinter hemorrhage. It happens for several reasons and can be harmless or even indicate of a serious health condition.

This condition is known as a splinter hemorrhage as it can appear like a wood splinter under your nail. The condition is brought by damaged small blood vessels below your nail. Characteristics include the below:

  • It’s black or red brown in color.
  • It doesn’t change its appearance when pressure is applied to the nail.
  • It appears on one or even more places under your nail.

Thicker lines which create a horizontal stripe on nail are known as Beau’s lines. These are not harmful, but they might also be a symptom of a cancer known as subungual melanoma.

What are the causes of a black line on the nail?

Black lines on nail can be due to several conditions.

Trauma is the most common cause of splinter hemorrhages. This might happen when something hurts the nail bed bursting a blood vessel under your nail. You might also experience nail trauma without realizing it, like when squeezing something tightly.

Endocarditis is a heart condition that leads to splinter hemorrhages. Fifteen percent of people with endocarditis experience splinter hemorrhages. Endocarditis happens when the inner chambers of the heart is infected. You can also experience other serious heart conditions due to endocarditis. Endocarditis generally happens in people who have preexisting cardiac conditions.

Psoriasis can also lead to splinter hemorrhages. Psoriasis is a chronic skin condition which manifests as silvery plaques, or scales on skin. Up to 50 percent of people with eczema experience splinter hemorrhages and several other nail conditions.

Causes of splinter hemorrhages include:

  • infections
  • lupus
  • lichen planus
  • medications which alters blood clotting
  • kidney or circulatory diseases
  • chemotherapy

Beau’s lines on all nails can be an indication of:

  • mumps
  • thyroid disease
  • syphilis

How is the cause of a black line on the nail diagnosed?

Contact your doctor if you’re sure that a black line on nail wasn’t brought about by trauma. If the trauma has led to another condition or doesn’t appear to be healing on its own after some weeks, then you should see your doctor.

If you suspect that the splinter hemorrhage is the cause of a serious health condition, then you should contact your doctor for an appointment and proper diagnosis. For instance, if you have the heart condition, you can experience symptoms such as fatigue, pale skin, and shortness of breath, among several others. Psoriasis can appear as a rash or scales on your skin, especially on your scalp, face, hands, and skin folds.

Splinter hemorrhages which recur or are affecting more than one nail is to be reviewed by a doctor.

The doctors will take a medical history and also perform a physical exam. Your doctor can also recommend further testing after your appointment if an underlying condition is also suspected.

Black Lines in Nails What Does It Mean

When a person has dark stripes that are running down their nails, then the explanations might range from something that is normal through to severe, like melanoma.

A person is not supposed to ignore changes to nails, especially if they are very painful and without explanation.

Fast facts on black lines on nails:

  • There are several causes of the condition, which are both of no concern and serious.
  • Treatment usually depends on discovery of the underlying cause.
  • A person is supposed to see a doctor after noticing a change to their nails that cannot be explained by a trauma.

What are the causes?

In some of the cases, black line on nail is brought about by melanoma.

Most commonly, dark stripes on a nail are because of a symptom called linear melanonychia. According to the United Kingdom’s National Health Service, the stripes commonly happen in people of African-American descent who are above 23 years of age.

Linear melanonychia is said to be a normal fingernail color variation. The condition happens when pigments in nail called melanocytes produce excess amount of pigment. This leads to the nail beds darkening.

According to an article in the journal Podiatry Today, an estimated 55 percent of African-Americans are affected by linear melanonychia.

Less common causes of the condition exist. They include:

  • taking some of the medications, like chemotherapy drugs, anti-malarial drugs, or even the medication azidothymidine
  • Lupus
  • scleroderma

Another cause of black line on nail is a splinter hemorrhage, which happen when the blood vessels under the nail are damaged, often because of the injuries, like hitting.

More seriously, a black line on nail can indicate the presence of a skin cancer, which is a dangerous form of skin cancer also known as melanoma.

Melanoma under a fingernail is called the subungual melanoma.

According to clinical guidelines that was published in the Journal of Foot and Ankle Research, about half of all skin cancers on the hands and feet are due to ALM.

Horizontal Black Line on Nail

Though is said that western medicine arguably has the best diagnostic tools that are found in the world, it is sometimes scoffed at when the medicinal treatments only deal with the symptoms, not the underlying causes.

When dealing with the diagnostic symptoms that are related to nails, it might be very interesting due to the widespread autoimmunity that leads to asthma which is technically treated using an inhaler, but you can still see inflammation in nails using guidelines that are from eastern medicine.

Horizontal nail lines run from side to side of the nail. When forming within or even on the surface of nail itself, the horizontal nail lines are also known as Beau’s lines. When they are deeper and formed , they are known as Mees’ lines.

Previous injury to your nail bed

Nails grow at a high rate. This implies that an injury to nail bed won’t show up for several months, until it fully grows out. You might not remember months-old minor events which traumatized the nail bed enough so as to create the horizontal ridges.

To avoid this in future, be careful when working with your hands. Though we all know that cutting cuticles is a very bad idea, it’s a bad idea to push back your cuticles harshly. In people who have soft nails, this damages the nail bed with ridges which won’t show for several months.

Underlying health conditions

It can sound scary, but most of the conditions that are associated with the horizontal lines on your nails are already known to you.

According to doctors, sudden illness, malnutrition, and the pain as well as the stress of carpal tunnel syndrome might stop the nail growth. When the nail starts to grow out, it can lead to horizontal lines.

Arsenic poisoning, renal failure, or Chemotherapy

Arsenic poisoning, renal therapy, and also chemotherapy can also lead to horizontal black line on nail. However, unlike trauma, these issues form deeper Mees’ lines within the nails, as opposed to lighter surface lines which are Beau’s lines.

It is clinically advised that you see a doctor immediately if you think you have Mees’ lines, especially if you have other several symptoms of heavy metal poisoning.

Black Lines in Nails Heart Problems

Black lines in fingernails normally emanate from splinter hemorrhages, which is bleeding under the nails. Splinter hemorrhages, which happen due to the blood vessel that is swelling or even the capillary damage, might indicate signal heart disease or several other heart conditions.

Lines in Fingernails

Lines in fingernails, known as splinter hemorrhages, might appear in shades of black or brown. The term “splinter” refers to appearance of small vertical lines that are under the nail bed.

Heart Disease and Splinter Hemorrhages

Splinter hemorrhages appear in the later stages of the endocarditis, which is a rare heart valve infection that is prevalent in people with underlying heart disease which leads to inflammation of heart’s inner lining.

Another condition, known as vasculitis, can also lead to black line on nail through an allergic reaction which damages the skin blood vessels.

Endocarditis and Vasculitis

Endocarditis results from germs which enter through several other areas of the body, like the mouth and thus infecting the heart. This rare condition usually emerges often in people who have existing heart diseases who undergo heart surgeries. People who are suffering from the condition normally develop painful skin lesions, like sores, blisters or even hives in several areas of the body.

Other Causes

If a heart condition exists, then other serious symptoms can appear which leads to concern and likely health monitoring before the splinter hemorrhages occurs. The doctors have indicated physical trauma to the nail and drug use through injections can lead to splinter hemorrhages.


If recent nail trauma has not happened, people who have black line on nail should visit a doctor for proper diagnosis as well as treatment of underlying conditions and causes.

Black Line on Fingernail Vitamin Deficiency

Fingernails indicate health problems by appearance. Nail abnormalities involve shape, color and thickness of nails.

Depression lines in the fingernails, also called the beau lines, happen because of malnutrition or an injury to your nail. Other possible conditions that can occur include koilonychia, fingernail pitting and ridges.

According to researchers, liver diseases and vitamin deficiencies can lead to nail abnormalities which includes fingernail ridges. Contact a doctor if your nails are appearing blue, clubbed or even horizontally ridged or if you see some white color under nails.

B vitamins are vitamins that have key functions which includes cell growth. Vitamin B-12 of B vitamin complex strengthening the nail growth; thus, a deficiency in B vitamins can lead to fingernail ridges. Iron deficiency leads to ridges in fingernails accompanied by white spots; Koilonychia is a condition of the nails that is associated with iron deficiency.

Other vitamins that cause other nail abnormalities are vitamin C, zinc and also calcium minerals. Poor absorption of vitamins will cause vitamin deficiencies. Consult a doctor if the horizontal ridges persist or if you notice discoloration like yellowness or even green nails.


A balanced diet that is rich in vitamins, minerals and also protein can assist in preventing fingernail ridges. Eat wholegrain foods, green vegetables and also fruits regularly so as to achieve the recommended intake levels for the vitamins. Consider supplements if your diet is lacking some amount of vitamins and nutrients. To avoid nail abnormalities, do not bite nails. Clip hangnails, keep nails short and also avoid use of the nail polish.

Black Line on Nail Melanoma

Skin cancer might happen under the nail. This occurs more frequently in dark-skinned individuals but it can occur in anyone. This cancer, also called subungual melanoma, appears as a dark strand that passes via the nail – especially on the thumb, index or great finger.

The black line on nail may be some millimeters wide or might be much wider. The line continues through your cuticle. Because people of color normally have darker streaks through their nail, this type of cancer is usually overlooked.

If you have this type of cancer, you might notice several other changes in your nail. These include thickening of nail, your nail lifting from nail bed, grooves in nail or even some pain in the area.

It is beneficial to have changes in skin, which includes your nails, properly checked by a dermatologist. This cancer accounts for only about 3 percent of melanomas, but, in people of color it accounts for about 40 percent of the melanomas.

When applying sunscreen, don’t forget applying to your nails and your skin. Some of the nail polishes now have the sunscreen in them.

Faint Black Line on Nail

  1. Lack of Nutrition

Your nails can give you insight into whether you are getting enough amount of nutrients, especially protein and calcium. You might also notice black line on nail if you have a zinc, or iron deficiency. Mild green or turquois streaks indicate hypersensitivity or tension.

  1. Bleeding

Bleeding underneath the nails is called a splinter hemorrhage and this leads to black line on nail. It can occur because of the blood vessel inflammation and affect one or several nails. The blood traces can seem brownish in addition to being blackish. You should ensure that you seek medical attention if the bleeding under nails is accompanied by symptoms such as elevated bleeding or fever.

  1. Fungal Infections

Fungal infections are usually considered to be a common cause of black line on nail. They may also cause thickening of your nail, thus creating an obvious deformity within the nail.

  1. Melanonychia

This fingernail condition includes the black line on nail, discoloration or excessive pigmentation. It is common in people who are older and also dark-skinned. It might be because of some medications, underlying medical conditions or injury to your nail bed, UV light exposure, or pregnancy.

  1. Nail Injury

Injuries to your nail can also lead to these black line on nail. They will mostly start at the bottom area of the nail before moving upward. It is possible that the lines form when a wood splinter becomes lodged inside your fingernail.



  1. Is Black Streaks in Your Fingernails a Cause for Concern:
  2. Black Line In Nail: Is This A Sign Of Melanoma:
  3. What Are The Effects Of Nutrient Deficiencies On Nails And How To Rectify Them:
  4. Do Vitamin Deficiencies Cause Fingernail Ridges:
  5. Black Lines in Fingernails & Heart Disease:
  6. What to know about a black line on the nail:
  7. What Are Splinter Hemorrhages:
  8. Black Line on the Nail: Should You Worry:



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