A B C D E F G H I J K L M N O P R S T U V W

SOLAR KERATOSIS

What is it ?

Solar keratosis is the name given to a pre-cancerous skin change produced by sunlight exposure. Pre-cancerous means that if solar keratoses are left untreated, then after many years they may develop into a cancer. It usually occurs in the elderly. In people who have lived in tropical areas or who work outdoors, it may occur at a much earlier age. Keratoses occur in areas of maximum sun exposure. This includes the face (and the scalp in bald men), the tops of the ears and backs of the hands. In manual workers, and people who regularly use sunbeds or who have repeated sun exposure, they may occur on the body as well. They vary in size and are generally flat. They invariably have a rough scale on the surface. This scale is often a darker colour than the normal skin, and the area feels rough, rather like a small patch of sandpaper.

How does it occur ?

Sunlight contains ultraviolet light which is responsible for tanning of the skin, sunburn and skin cancers. Over the years, the skin is exposed to considerable amounts of ultraviolet light. Eventually, the amount of exposure exceeds the level which the skin can tolerate. Both pre-cancerous and cancerous skin lesions then develop.

Why does it occur ?

The body's protection against ultraviolet light damage is skin pigment. People with pale complexions, and who burn badly in sunlight, tend to develop solar keratoses more easily than people who tan easily, or who have naturally dark skin.

Treatment Involved

Solar keratoses are easily treated with a number of different treatments. They can be surgically removed by cutting out the affected area of the skin after local anaesthetic and sewing up the normal skin. This is not usually necessary unless the diagnosis is in doubt and the doctor wishes to make sure that nothing else is occurring in the skin. Solar keratoses can be curetted (scooped off the skin using a sharp surgical spoon). The area is then cauterized. Most specialists will treat solar keratoses by freezing them, a treatment called cryotherapy . This involves either dabbing or squirting a very cold liquid (liquid nitrogen) on to the skin. This causes a burning sensation at the time, and the treated area will almost certainly blister and then scab. Once the scab has separated, the skin should be normal. A special cream containing the drug 5-fluorouracil is often used for treating solar keratoses, particularly when large numbers are present. This cream destroys the abnormal cells, thus allowing the normal cells to repopulate the skin. Treatment is usually used on a daily basis for 4 weeks.

During Treatment

If the keratoses are removed surgically, this will leave small scars. Stitches will need to be removed after 7 to 10 days. If the areas have been curetted and cauterized, there will be a small painful area at the site of treatment. Over the next week this will scab over, leaving a small, slightly sunken scar. If the keratosis has been treated with cryotherapy, it will swell up and blister within 2 to 4 hours of treatment. You should not keep the area covered up, as this may lead to infection. Over the next week the site will scab and eventually leave a small red patch which will fade to normal skin. The 5-fluorouracil cream causes considerable irritation in the skin. Within 7 to 10 days of starting the cream, the skin will become red and itchy and may become very weepy as well. The doctor can provide a cream that can be used in addition to the 5-fluorouracil cream. This will reduce the irritation and inflammation. It is important that treatment is continued for a full 4 weeks, otherwise the skin will not be completely cleared.

After Treatment

Solar keratoses are a sign that the skin has been damaged by sunlight. Almost certainly more of these will develop in the future. You should use a high factor sunscreen lotion which may help prevent them.

If Left Untreated

Solar keratoses improve during the winter months and may fade completely, but will generally come back again during the summer. If left for a period of 10 to 12 years, there is a significant risk that one of these will develop into a condition called squamous cell cancer.

Effects on Family

Sensitivity of the skin to sun exposure tends to be inherited. It is therefore clearly in the interest of your relatives that they protect their skin from sun exposure from an early age to prevent keratoses from developing. This will also then protect them against the longer-term problems of skin cancer. Since the damage which sets the problem off begins at a very young age, it is particularly important for children to avoid sunburn and excessive sun exposure of the skin. Sunlight exposure to the skin is damaging.