Changes to your fingernails are often nothing to worry about. However, sometimes, your nails go through a change in shape, colour or structure because of an underlying illness or condition.

If you've recently noticed small streaks that are a brownish-black or even red colour under your nails, then you want to find out what's going on. Known as splinter haemorrhages, these marks sometimes have an obvious and harmless cause, but they might also be a sign of something else going on in your body.

Why have these marks suddenly appeared? How can you tell if you need to see your GP or not?

Have You Injured the Nail?

If you've had an accident on your hand or fingers, then splinter haemorrhages may be related to what happened. These lines are tiny streaks of blood that come out of a damaged blood vessel under the nail.

For example, if you trapped your finger in a door, then some of the blood vessels may have broken leaving these marks behind as the swelling and bruising goes down. Even a slight bash on the nail that didn't seem serious at the time can make this happen.

How Many Nails Are Affected?

Look at all your fingernails and see how many have these streaks in them. Typically, if the lines are down to accidental damage, you'll only see streaks on the affected finger. However, if the accident affected a couple of your fingers, then all of those nails may show some damage.

If you can see streaks on multiple nails or even on all of them, and you're pretty sure that you haven't had an injury or accident, then the streaks may be connected to something else. For example, some people with psoriasis or heart problems are more prone to splinter haemorrhages.

Should You See Your GP?

If the streaks are down to nail damage, then they should heal themselves over time and shouldn't come back. However, if you hurt your finger in other ways or notice other nail changes, then it might be worth popping into your clinic to check that you haven't broken anything or are at risk of infection.

If you have splinter haemorrhages on multiple nails and you can't identify a reason why they are there, then you might want to contact your GP to have a check-up. While these marks aren't likely to be a problem, it's better to get a professional opinion.