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Arm Mole Count May Predict Skin Cancer Risk

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Moles, or nevi, are benign tumours found on most adults. Despite continous skin cancer research, why we develop moles and why some people have more moles on their arms, legs, or back remains largely unknown.

A mole, or nevus, is formed when the cells that produce pigment, called melanocytes, grow in groups.  

What we do know is that the more moles you have, the greater your risk of developing skin cancer. One recent study found an interesting link between where those moles are located on the body and how many we are likely to have overall. 

So let's look at what those researchers found about the meaning of moles on the arm and what to do if something doesn't seem right with a particular mole. 

Moles on right arm may predict melanoma risk 

Freckles on crossed arms

The results of a study by researchers at King's College London may make it easier for doctors to quickly assess a person's risk of melanoma. According to the study, those with 11 or more moles on their right arm may have a greater risk of skin cancer compared to other people.

Experts involved in the study found that the number of moles on the right arm proved to be a strong predictor of the total number of moles on the subject’s body.  

  • People with 7 or more moles on their right arm were at higher risk of having 50 or more moles on their entire body.
  • People with 11 or more moles on their right arm had a greater chance of having 100 or more moles on their bodies.

Benign moles may unlock a greater meaning

The research was conducted on a group of 3,594 female twins over eight years. Specially trained nurses carefully examined 17 areas of the patients' bodies. In addition, the team also took some other factors into consideration, such as their skin type, number of freckles and eye and hair colour.

Whilst not disregarding other important melanoma risk factors, this is a quick way for doctors to assess a patient’s risk of melanoma by counting the number of moles on their right arm.

Look above your right elbow for moles

While entire arms were examined for the purpose of the study, the researchers found that it was the area above the right elbow that proved to be a particularly strong indicator of the number of moles on the body.

The study helped the researchers to conclude that there exists a strong correlation between mole counts on the right arm with total body mole counts. The rationale is that, because 11 or more moles on the right arm is an indicator of 100 or more on the body, this in itself is associated with an increased risk for melanoma.

How do arm moles impact your risk of skin cancer?

Right arm reaching out

The presence of pre-existing moles is one of the first things doctors look for while performing a skin cancer check. Why? Around 20-40% of melanomas arise from pre-existing moles.

An analysis of more than 40 different studies also concluded that people with more than 100 moles have a seven times greater risk of developing melanoma compared to people with 15 moles or less. 

What are some other skin cancer risk factors?

Even though the presence of large numbers of moles indicates a higher risk of melanoma, there are also other risk factors you should be aware of: 

  • If you have a family history of skin cancer, you are also more likely to develop it in your life.
  • People with a lighter skin type who normally also have fair hair, skin or eyes, are more susceptible to sun damage and more likely to develop skin cancer throughout their lives.
  • Although benign, atypical moles can resemble cancerous moles. They are typically more than 6mm in diameter and can have irregular borders. Having a lot of these types of moles can increase your risk of developing malignant melanoma. 
  • A history of sunburn and unprotected sun exposure, particularly in childhood, can damage skin cells and put you at greater risk of skin cancer. 
  • The use of indoor tanning beds exposes you to additional, harmfulUV radiation.

What does a new mole on your arm mean? 

Suspected skin cancer spot on arm

Whether it's a mole on your left arm or a mole on your right arm, the appearance of a new mole on any location of your body requires caution and close attention.

Squamous cell carcinoma

What you think is a new mole on your arm could in fact be a skin cancer. More common than melanoma, a squamous cell carcinoma usually looks like an abnormal skin growth or lesion. It may have the appearance of a mole, wart or ulcer, or it could be a spot that is crusting or a sore that is painful and does not heal. It may also begin bleeding for no reason.  

Basal cell carcinoma

A basal cell carcinoma could also be mistaken for a new mole on your arm. They too can present as an abnormal growth that looks a bit like a wart or mole. In fact, they can be dark (brown or black) or they can look like a white mole or waxy-coloured lump, or even be pink.

Basal cell carcinomas can also itch, look scaly or crusty, or just like a red patch, bump or a sore spot that won't heal. People can even mistake them for scars. These growths present with raised edges or a central indentation. 

I have a mole on my arm I want to get rid of. What next?

Doctor giving a Mole Check

The first step is to have your mole examined by a doctor by booking in for a mole check. The doctor will use a hand-held microscope called a dermatoscope to closely examine your skin. 

If the doctor finds a mole or spot that looks suspicious, they will perform a biopsy to remove a sample of cells so that it can be tested in a laboratory. If it is thought that a mole is a melanoma, they may perform a type of surgery called an excisional biopsy to remove the mole

When should I worry about a mole on my arm?

Cancerous mole dark spot

It's important to know what's normal for your skin and tell your doctor about any symptoms or changes to a mole such as its surface texture, size, shape or colour, because it could be a sign of cancer. 

Performing a skin exam at home is an easy way to keep an eye on your moles for any difference in appearance. But it's important you don't just look at your arms because melanoma and other skin cancers can develop anywhere on your body. 

How to spot melanoma warning signs

There are some warning signs of melanoma to look out for using the 'abcde' technique

  • Asymmetry - If you were to draw a line down the middle, one half would look different to the other
  • Border - The spot has an irregular or ragged edge
  • Colour - Various colours are present 
  • Diameter - Greater than 6mm in diameter (about the size of a pencil eraser) 
  • Evolving - Changes to the size (increased elevation or spread), shape, texture or feel, or colour of a growth

A self-examination of your skin will help you detect these melanoma symptoms. It's important to remove all of your clothing and use a hand-held mirror to examine your scalp, face, neck, back, buttocks and the backs of your legs and arms. You may also like to take an image with a mobile phone.

Don't forget to check the soles of your feet, palms of your hands and fingernails and toenails. 

Take steps to protect yourself from skin cancer 

Men, women, and in rarer cases children, can get skin cancer. Use the mole count on your right arm technique but also take into consideration the other risk factors listed above to boost your skin cancer awareness. 

Early detection of skin cancer can save lives but prevention is just as important. Remember the importance of protection from UV radiation by always wearing sunscreen to avoid burns and seeking shade during the hottest part of the day. 

Put your health first and have your moles checked 

No matter your age or stage of life, if you find suspicious spots or suspect a problem with a mole, it's vital to seek advice from a doctor as soon as possible. While self-exams are important, there is no substitute for a comprehensive skin check with a doctor who specialises in skin cancer detection and treatment. 

The skin cancer experts at SunDoctors offer a variety of services and take patient care seriously. Give them a call on 13SKIN (13 7546 ), or book an appointment online.

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