Experts reveal 'harmless-looking' skin changes that are actually signs of cancer - it's not all about moles

Daily Mail​

27-05-2025

Experts have flagged little-known warning signs of the most dangerous types of skin cancer—and many do not involve a new or changing mole.
Dermatologists have detailed the other key red flags of dangerous melanoma that few patients are aware of, including changes to the nails and genitals.
It comes as shock new research today revealed the parts of the body most likely to be susceptible to skin cancer vary between men and women.
According to the Cancer Research UK study, the majority of melanomas in men are found on the torso, including the back, chest and stomach—equivalent to around 3,700 cases a year.
Women, meanwhile, most commonly develop the lesions on the legs, from the hips to the ankles, accounting for 3,200 cases every year.
Melanoma is the most dangerous type of skin cancer, accounting for four out of five deaths, but only one per cent of total cases.
Yet, rates of the disease are predicted to soar yet again this year—up a fifth in just two years.
Below, experts tell MailOnline of the surprising skin changes that could be sinister.
Dark patches on genitals
Melanoma can present as dark lesions on the mucous membranes, meaning the inside of the nose, mouth, vagina, or anus, or the fingers and toes.
This subtype of aggressive cancer is exceedingly rare and accounts for less than two percent of all melanoma cases.
Unlike other types of melanoma, mucosal melanoma is not affected by sun exposure.
About half of the mucosal melanomas start in the head and neck, typically the nose, mouth, windpipe, or esophagus. Smoking, ill-fitting dentures, and ingesting or inhaling carcinogens all greatly compound the risk of sarcomas in the mouth.
Most of the remaining 50 percent of melanomas begin in the anus or rectal region and the female genitals. Spots on mucosal areas might not be melanomas but rather squamous cell carcinomas.
Dr Nayoung Lee, a dermatologist at NYU Langone Health said: 'Initially when it's early it kind of looks like a whitish bump or ridge on the mucosal surface.
'So as it grows it starts to look more like an ulcer, it can look fungated [like a fungal infection in appearance], or other things.'
While doctors have not pinpointed the exact cause of mucosal membrane melanomas and non-melanoma cancers, some believe they are linked to a viral strain of human papillomavirus (HPV).
HPV strains 16 and 18 are those deemed high risk and cause the vast majority of cervical cancers. But strains six and 11, lower risk varieties, are more commonly associated with non-UV-linked skin cancers inside our bodies' orifices.
Dr Zaineb Makhzoumi, a dermatologist at the University of Maryland, also said: 'The subtypes that are causing a cervical cancer are not the same subtypes that are causing skin cancer.'
Patients can sometimes mistake nonmelanoma cancers in the genital region with a sexually transmitted infection, but doctors want to drive home the fact that this type of cancer is not a sexually transmitted disease.
Changes to fingernails
When the disease starts under the nail it is known medically as subungual melanoma and typically presents as streaks or bruises on the nail bed that do not heal or grow out.
They commonly appear as a dark brown or black streak.
The nail may also become thicker, separate from the nail bed and split down the middle.
Another concerning sign of the disease—which accounts for around one in 30 melanoma cases—is if pigmentation starts to creep up and discolor the skin beyond the nail.
But if the thickness of the nail changes, and becomes yellowed, it could be another type of nail cancer called onychomatricoma.
Black spots and streaks, however. are not necessarily a sign of cancer. It could also be harmless pigmentation, known medically as longitudinal melanonychia.
Dermatologist Dr Lindsey Zubritsky, who goes by @dermguru on Instagram, said: 'Not all dark streaks on the nail are dangerous, many people have a benign streak on their nail called longitudinal melanonychia, which is totally normal.
'It's more likely to be benign if it is lighter, it's not changing in colour, it's found on multiple nails or you have a darker skin tone.'
Grey or purple blotches
According to Macmillan Cancer Support, melanoma that has spread to areas of the skin far away from the original melanoma appears as firm or hard lumps called nodules.
It does not always appear raised, though, and could resemble a flat scar or blotch. Typically these areas are grey or purple areas of skin and may bleed.
Earlier this month, one GP from from Kinross, Scotland also warned the public to pay attention to any change to their skin, even if it doesn't involve a mole, after he was dealt a shock skin cancer diagnosis that has since spread to his leg and pelvis.
Alastair Muir, 63, noticed a skin-coloured lesion on his heel back in 2018 and suspected that it was a wart or verruca, and attempted to have it frozen off.
But a biopsy taken later that year revealed the devastating truth—it was in fact melanoma.
'Most people associate melanoma with pigmented moles that change or grow,' he said.
'It is important for people to know that it doesn't always present that way.
'I think people need to be aware that if you have anything on your skin that is different or changing then it is very worthwhile getting it checked out.'
Dry scaly patches
In rarer cases dry scaly patches of skin could also be a subtle sign of melanoma.
Dr Saira George, an associate professor of dermatology at the University of Texas, said: 'Dry skin patches or rashes that aren't getting better with treatment, are causing a lot of symptoms, or are occurring in unusual sites on the body where you haven't had scaly patches before might be signs of something more than run-of-the-mill dry skin.
'But dry, scaly skin is a common presentation for many things and most dry, scaly skin is not skin cancer.'
More often than not, it could be a sign of non-melanoma skin cancer—a group of cancers that slowly develop in the upper layers of the skin.
One, squamous cell carcinoma, is caused by an overproduction of squamous cells in the epidermis, the top layer of your skin.
In many cases, patients have rough, scaly patches or growths, sometimes with a crusty or bleeding surface.
Dr Lee said: 'They just feel scaly so you can feel them more than see them.'
People that have a history of heavy sun exposure are most likely to experience this type of skin cancer.
With every bad, blistering sunburn comes a heightened risk of squamous cell carcinoma.
Fair-skinned people and those with light eyes who are more prone to sunburn are also more vulnerable.
More often than not, though, the condition is curable when treated early. In fact, the survival rate is as high as 98 percent.
A rough patch or sore that bleeds may indicate another type of non-melanoma skin cancer called basal cell carcinoma which, like SCC, has a high survival rate. Still, people should treat it aggressively once it's detected.
Dr Lee added: 'Depending on location they can grow deeper in muscle and bone, so they do become problematic if left to grow for a long period of time.'
Basal cell carcinoma is the most common type of cancer overall and the most common type of skin cancer more specifically.