What your nail ridges reveal about your health

What ridges on your nails mean, what is normal and what is a sign of disease – and when you should call the doctor

Our fingernails are our version of animals’ claws, made from the same substance – keratin – as our hair, and the hooves and horns of vertebrates. They grow twice as fast as our toenails, faster in men than women. They don’t hurt when you cut them because, apart from the small moon, the part we can see is dead. So far, so fascinating. But what if you look down and see that you have developed ridges where there used to be none? Should you worry?
There are two types:
Dr Dhruvkumar Laheru is a consultant dermatologist and the nails lead for the British Hair and Nail Society. He explains: “Usually horizontal ridges are a sign that some form of interruption or change has happened in the growth of the fingernail.” But he adds this is not necessarily a diagnostic tool for an existing condition, as it is usually something that has happened in the past. 
“Ridges are a bit like rings in a tree, they’re a marker of things that happened a while ago, a bit like a glacier – it flows forward like a river, but is incredibly slow.” 
For a nail to grow from the beginning, forming under the cuticle in the nail matrix, to the end where you clip it off, takes around a year for a fingernail and two years for a toenail in an adult. “So for things that happened to show up as a horizontal ridge would have happened a while ago.”
(And it’s not true that fingernails continue to grow after you die – the effect is caused by skin dehydrating and tightening, making the hair and nails appear to grow.)  
“Close to anything can happen that can lead to ridges,” says Dr Laheru. Typical and common causes of horizontal ridges are internal, or external traumas, that have caused growth to be interrupted. 
“Internal issues can include serious illness, from bad pneumonia to flu, or treatments such as chemotherapy. 
“Externally this would include trauma – injury to the nail or the nail matrix itself, such as hitting your finger with a hammer or slamming your finger in a door. 
“The horizontal ridges are called Beau’s Lines [deep grooved lines that run from side to side on the fingernail or the toenail]. If the white moon at the bottom of the nail is traumatised, it can cause horizontal ridges.”
Traumas can also be the result of manicures, says Dr Laheru. “Manicures affect the nail in mostly physical senses – heat application, chemicals, adhesives as well as cuticle disruption – so may all contribute to Beau’s lines.”
In addition, cutting or picking at cuticles and skin conditions including eczema and psoriasis can cause trauma and cause lines which signify an interruption in normal growth. “Your nail puts itself on pause while it’s healing,” Dr Laheru explains.
The most common cause of vertical ridges is simply ageing and over time you may notice these appear across all nails. “But think of it the other way round. It’s not the ridges that have come up, it’s the other parts that have gone down. Quite simply it’s the same as getting wrinkles in the body – the areas of the skin that dip down are the areas that are causing wrinkles in nails – the very fine longitudinal ones.”
“By and large anything that happens to your skin on your body can happen to your nails because it’s the structure of your skin,” says Dr Laheru.
“Anything can happen to the body, there is a theoretical chance that it could manifest in some way in your nail.” 
Examples include medication, or other completely unrelated medical conditions, which cause skin and nail changes. 
Mild fungal infection is very common and generally causes longitudinal, rather than horizontal, ridges. He adds: “There are rare conditions where people can get skin cancers and nail cancers just like you can get anywhere else in your body.”
Although some sources point to various diseases, including uncontrolled diabetes, as being associated with Beau’s lines, Dr Laheru is quick to point out: “Any sort of trauma (be it physical or physiological for the body through internal illness) can lead to a temporary interruption in nail growth, experienced by the nail matrix, and then can result in a Beau’s line. However, that’s not to say that it’ll happen everytime someone gets an illness.”
The key to whether you should get any changes to your fingernails checked out is whether it appears on all your fingernails or just one. Usually longitudinal ridging appears on all fingers, but, says Dr Laheru, you should question it when you see longitudinal ridging in a select isolated digit.
“If you’re going to get wrinkles, you’re probably going to get them everywhere, but if you just get one fixed wrinkle or ridge that is probably a reason to pay more attention to this condition. 
It would be a prompt to go to your doctor – it doesn’t necessarily mean there would be anything wrong – or you may just be catching something at the very start of a process. But if you find that it’s persisting in one particular digit that’s more of a prompt to get it checked.”
“It doesn’t mean there is something wrong but something is changing,” says Dr Laheru. You will obviously know if you have hit it with a hammer or have a rose thorn inside the nail that is self-explanatory but anything unexplained, check it.”
If you have repeated Beau’s lines it could be a sign that you have a condition that keeps interrupting the growth of your nails and you should ask your doctor. 
Although it is widely reported that ridges can be a symptom of a mineral or vitamin deficiency, Dr Laheru says that this is extremely rare in a country like the UK – in fact he has never encountered it. 
“It’s pretty rare in the UK that someone’s diet has a nutritional deficit that manifests elsewhere. You would have to have a pretty restricted diet for a medical condition to be picked up by a fingernail sign only.”
What about white spots?
“They are usually from a physical trauma. People usually think it is a nutritional deficiency but it’s usually not.”
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