Almost 90 per cent of respondents to a survey had never heard of the common skin disease solar keratosis, despite the fact it can affect up to a third of older people.
About 1,800 cases of keratosis are diagnosed in the South East every month and a fifth of these can go on to form skin cancer.
Marie Curie Cancer Care joined forces with The Royal Life Saving Society UK (Lifesavers) on Brighton beach to launch an awareness campaign called Solarcraze.
Those taking part in the event were Teresa Tate, medical advisor to Marie Curie Cancer Care and John Korving, 65, who has been successfully treated for the condition.
Mr Korving said: "I had never had any problems until, one day, I noticed a rough patch of skin on my cheek.
"It seemed to tingle a little and, like most people, I left it at first because I thought it would disappear of its own accord.
"It was itching a little and I kept picking at it but did not worry too much. After a few months, it was still there so I decided to go to my GP.
"The condition was eventually diagnosed as solar keratosis and I had special laser treatment to get rid of it.
"Unfortunately, it came back again but after another dose of treatment, it went away and has never returned.
"In my case, there was no problem with cancer but it shows if you have any concerns, you should get them checked out as soon as possible.
"I'm not the sort of person who goes to hot countries or lies out in the sun all the time. In fact, I tend to try and avoid it.
"This shows the condition can affect anyone, even if they are only exposed to the sun while going out and about."
Despite the fact 69 per cent of people surveyed in the South East say they know they should consult a health professional right away if they see new marks or moles on their skin, more than 70 per cent admitted they have not consulted a doctor about skin marks within the past five years.
Consultant dermatologist Neil Walker said: "Solar keratoses are a real and growing threat. Although most are not sinister, some world experts now argue a solar keratosis is an early form of a cancerous cell and it is important it is assessed and treated if necessary."
Solar keratoses are small crusty or scaly skin bumps that may feel itchy or prickly. They are caused by excessive sun exposure and can be easily treated if diagnosed at an early stage.
Newer therapies applied directly to the skin, such as a gel, can avoid side effects of older treatments.
A survey found almost 90 per cent of those surveyed did not realise these less aggressive alternatives were available.
Dr Tate said: "There is still a huge need to make sure people check their skin regularly for the early signs of cancer.
"It is shocking that even now, one in four of us would wait, ask a friend or relative or do 'something else' rather than seeing a nurse or a doctor straight away about new marks on our skin."
A special patient information leaflet titled "Do you have sun-damaged skin?"
has been produced as part of the new Solarcraze Campaign and will be distributed in pharmacies across the UK to alert people to the need to seek medical attention.
The Royal Life Saving Society says helping make sure sun seekers enjoy Britain's beaches safely is as much about preaching the Solarcraze message as it is about saving people in trouble in the water.
Chief executive Di Standley said: "Our message to the public is don't go "solarcrazy" in the sun this summer.
Solar keratosis is a condition that is easily diagnosed and treated. If you see a new or unusual mark on your skin, consult a health professional right away."
This year, about 65,000 people in the UK will be diagnosed with skin cancer.
It is the second most common type of cancer in the UK after lung cancer and is almost always caused by exposure to the sun.
Over the past 15 years, the incidence of skin cancer has doubled and the numbers continue to rise.
Skin cancer can be prevented and The Health Of The Nation target for skin cancer is to halt the year-on-year increase in its incidence by 2005.
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