Sun spots, known as actinic keratosis or solar keratosis, are precancerous spots that occur on skin that has been sun damaged. They may be light or dark, tan, pink, red, a combination of these, or skin-colour. They vary in size and can be raised or flat. The scale or crust is horn-like, dry, and rough, and is often recognized easier by touch than sight. Occasionally they itch or produce a pricking or tender sensation, especially after being in the sun. They are mostly seen on the face but can also be seen on other sun exposed areas of the body such as on the back of hands, arms and leg.
People more at risk of developing precancerous spots include people who:
- Have fair complexion
- Over 40 years old
- Spending large amounts of time outdoors without skin protection
- Use solariums or tanning beds
- Have had an organ transplant
Actinic keratosis are of concern as they have the potential to progress to squamous cell carcinomas. The rate of conversion is thought to be about 5-20 per cent or about 10-15 per cent with those with more than ten solar keratosis. It is important for people with precancerous sun spots to get them checked regularly by a doctor to observe these changes.