Information on solar keratoses and sun spots

Solar keratoses are scaly spots, red or occasionally brown in colour.  They are often referred to as “sunspots”.

They appear on areas of skin that are frequently in the sun – most commonly the face, ears, neck, forearms, back of hands, legs and the scalp in balding men. The spots vary in size: usually from a few millimetres to 2 centimetres across. They are not painful or itch, but may sting when in the sun or if they are scratched.  Solar keratoses are not skin cancers, but like skin cancers, they are a result of exposure to the sun, and signify sustained sun damage and the potential of developing skin cancer is increased.  Occasionally, they may change into skin cancer.  Solar keratoses are among the strongest determinates of skin cancer. Their presence increases the risk of BCC (Basal Cell Carcinoma) by 3-fold and SCC (Squamous Cell Carcinoma) by 12-fold. Up to 60% of invasive SCC arise form solar keratoses.

Solar keratoses are a warning sign that you are at risk of skin cancer: skin cancers are more common in people with solar keratoses. If you have a solar keratosis, you should watchout for other signs of early skin cancers.

The prevalence of solar keratoses is age –dependent, but can occur at any age depending on the history of sun exposure and skin type. Those at increased risk of developing solar keratoses have Anglo-Celtic or fair skin. A history of even one episode of sunburn in childhood increases the risk of solar keratoses six-fold in later life. The more sun damage there is during childhood the more likely you are to later develop solar keratoses.

In Queensland, about 40% of young and middle –age adults have solar keratoses, and one study found that 18% of adults had more than 10 solar keratoses.  Solar keratoses can regress spontaneously (usually with sun protection) but this is not common occurring in perhaps less than 10% of cases.

Solar keratoses can be treated by various methods including topical creams, cryotherapy (dry ice) or PDT (Photodynamic Therapy).

The topical creams need to be applied regularly over a 4 week course and result in local skin reactions which can be quite noticeable eg EFUDIX (5 fluorouracil twice daily for 4 weeks) or ALDARA (Imiquimod one sachet 3 times per week for 4 weeks)

Cryotherapy includes the use of freezing with liquid nitrogen which is applied to each lesion for 20 – 40 seconds.  It may need to be repeated, and may leave areas of hypopigmentation, i.e. white areas where normal pigment has also been removed. PDT or Photodynamic Therapy is a newer treatment, mainly used on the face that involves the application of an amino acid to the skin, which is then activated by a light source.  Whilst it can cause significant redness and sun sensitivity for 48 hours it has the advantage it can target areas of sun damaged skin before they become obvious.

For more information see Photo Dynamic Therapy Sun Damaged Skin

Related Items

• Sun Effects On Skin
• Photodamaged Skin
• Skin Cancer