A splinter hemorrhage is an area with blood under the nail, resembling a splinter. It is also known as a fingernail hemorrhage and consist of lines of hemorrhaging that can appear under both fingernails and toenails, often with a straight line.
These lines can develop because the nail's structure consists of vertical grooves, with a dense network of small blood vessels. Even the slightest bleeding under the nail will be channelled in one of these grooves and produce the splinter hemorrhage effect. These are almost always in a straight line, since the nail bed has a linear structure. The bleeding stops as soon as small clots form to contain it.
Splinter hemorrhage is caused by minor bleeding that occurs under the nails. The bleeding resembles a splinter under the nail's surface. It looks like either a red or a brown straight line, along the nail groove.
This condition is usually harmless and rarely painful. In most cases, it is even difficult to spot and you might only notice it after some time. However, it is possible that the bleeding is caused by trauma, like a direct injury on the nail. In this case, the bleeding might come with some pain, as well as redness, inflammation and swelling.
The most common cause of splinter hemorrhages is an injury to fingernails or toenails. The impact causes damage to the tiny blood vessels located under the nail, leading to bleeding along the nail bed that looks like a straight line.
If a trauma is the cause of splinter hemorrhage, there is no reason to worry because the damage will heal in time and the line will disappear. However, it is possible that the splinter hemorrhage is actually a sign of a more severe disease.
If you have a splinter hemorrhage but there wasn't any nail injury or trauma, it is possible that it was caused by an underlying disorder that affects blood vessels in general. Possible causes include a type of blood vessel inflammation named vasculitis, the presence of bacteria in the blood stream that travel all the way to the blood valve (bacterial endocarditis) or nail infections of a fungal nature that cause blood vessel damage by thinning the nail bed. Other diseases that can cause it are very high blood sugar levels triggered by diabetes, which harms blood vessels, as well as Raynaud's disease, which makes fingers and toes too sensitive to cold, hurting the nail bed capillaries. A build-up of cholesterol in the tiny blood vessels in the fingers can also cause them to burst. Many systemic disease hurt veins in general and can cause splinter hemorrhage as a side effect, for example nail psoriasis, lupus, rheumatoid arthritis, malignancies, scleroderma or peptic ulcer.
Some types of medication, such as drugs that counter inflammation but are not based on steroids, can also cause this side effect. In most cases, bleeding only happens when the dosage is very high.
The vast majority of splinter hemorrhages are considered harmless because they are the result of an impact or direct injury to the nails. These can't be prevented and shouldn't be a cause of concern at all.
Most people develop splinter hemorrhage due to an active lifestyle. Sports like jogging, tennis or hockey can often result in mild nail trauma and minor bleeding. Even outdoor activities with a lower intensity, playing with a Frisbee for example, can injure the nail bed and lead to bleeding from the capillaries.
It is possible that splinter hemorrhages actually signal a more dangerous disease and are just a side effect of it. Fungal infections, known as onychomycosis in medical terms, are one of the possible causes. Another condition that can lead to bleeding under the nails is nail psoriasis. This disease causes the top nail bed layer to become thinner than normal, which brings the network of capillaries close to the nail plate, increasing the risk of bleeding.
There are also a number of medications that can increase the risk of splinter hemorrhages. A notable one is the widespread aspirin, which reduces the speed of blood coagulation. Many other drugs available without a prescription can cause the condition, especially painkillers and products against arthritis.
Endocarditis is a heart valve condition that can also lead to nail hemorrhages, in rare situations. However, this disease has much more serious symptoms, such as heart murmurs, high fever or anemia.
Since this condition has multiple possible causes, treatment options are variable. In most cases, splinter hemorrhages are just the result of an injury to the nail bed and no treatment is required. Some of these splinter hemorrhages heal on their own after just a few days. Others persist and only clear after the nail grows enough to eliminate them. In such cases, the process might last a long time, even several months, due to the very slow nail growth rate. Toenails grow slower than the finger ones.
Nail trauma can also be painful. This can be countered with several drugs that don't require a prescription or using simple home remedies. A very effective one is to just put a cold compress on the nail, which can also reduce inflammation.
If the splinter hemorrhage is the side effect on another disease, the root cause has to be addressed first. In most cases, the nail issue will also disappear after the main condition is cured.
Depending on the underlying disease, there can be various forms of treatment. Fungal infections for example can be cured with both prescription drugs and over the counter ones. Nail psoriasis, rheumatoid arthritis or other general systemic diseases can be treated with prescription medications such as corticosteroids or drugs that suppress the immune system.
Bacterial endocarditis can be corrected through surgery, which repairs heart valves and restores their normal shape. Antibiotics can also eliminate the infection.
As for medications that cause splinter hemorrhages as a side effect, the condition usually disappears after the drug is no longer administered.