Globally, skin cancer is one of the most common forms of cancer with the World Health Organisation reporting up to three million cases every year.
There are two main types of skin cancer – melanoma and non-melanoma. Melanoma skin cancer is much less common than non-melanoma but is more dangerous.
This is because it can spread to other parts of the body. It develops in cells that produce melanin – the pigment that gives your skin its colour and helps protect against sunburn.
As would be expected, symptoms of skin cancer typically appear on the skin. Many people are aware that the appearance of a new mole is something to be cautious about for this reason.
However, there are a number of other symptoms that should raise alarm bells that can appear in areas of the body you might not even think about.
According to experts at the American Academy of Dermatology Association (AAD), some signs of a melanoma can appear on the feet.
They warned that many people might miss these signs, leading to a missed or delayed diagnosis.
They said: “Melanoma, the most serious skin cancer, develops on skin that gets too much sun.
“It can also begin in places where the sun rarely shines, such as your foot.
“Because most people never check their feet for signs of melanoma, this cancer often spreads before it’s noticed.
“Allowed to spread, melanoma can turn deadly. By checking your feet, you can find it early when it’s highly treatable.”
The experts shared six specific warning signs of melanoma on your feet. These are:
- Brown or black vertical line under a toenail
- Pinkish-red spot or growth
- New spot or growth where you injured your foot
- Rapidly growing mass on your foot, especially where you once injured your foot
- Non-healing sore on your foot (or a sore that heals and returns)
- Sore that looks like a diabetic ulcer.
Experts at the AAD added: “Sometimes, melanoma on the foot feels painful, bleeds, or itches, but not always.
“The bleeding tends to stop and start.”
You might also experience any of the more well-known signs of skin cancer on your feet.
These are moles or pigmented spots that are unusual or change appearance.
To identify these you can use the ABCDE method:
- Asymmetry – one half of the spot is unlike the other half
- Border – the spot has an irregular, scalloped, or poorly defined border
- Colour – the spot has varying colours from one area to the next, such as shades of tan, brown or black, or areas of white, red, or blue
- Diameter – while melanomas are usually greater than 6 millimetres, or about the size of a pencil eraser, when diagnosed, they can be smaller.
- Evolving – the spot looks different from the rest or is changing in size, shape, or colour.
If you spot any of these symptoms you should speak to your GP.
How to check your feet for melanoma
The AAD recommends checking the following areas of your feet:
- Entire bottom of each foot, including the bottoms of your toes
- Top and sides of each foot
- Between toes
- Toenails.
The AAD says: “By thoroughly checking your feet, you can find melanoma early.
“Pay close attention to places on your feet that have been injured. Even if the injury was years ago, examine the area carefully.”
Research has shown that a foot injury may increase your risk of developing melanoma.