Author: Vanessa Ngan, Staff Writer; Copy Editor: Clare Morrison; Chief Editor: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, October 2013. About Melanoma is sponsored by the New Zealand Dermatological Society Incorporated.
In New Zealand, most melanomas are related in some way to ultraviolet radiation (UVR). UVR comes from the sun or from man-made sources such as sunbeds and tanning salons. UVR on the earth's surface is composed of short wavelength UVB and long wavelength UVA rays.
UVR damages skin cells and affects the immune system.
There is more UVR when the sun is overhead in the middle of the day and in summer.
There is also more UVR at high altitude or when the sun's rays are reflected from a white or shiny surface such as snow or beach sand.
Sunbeds produce a high level of UVR.
Sources of high exposure to UVR
Sun at the beach
Reflection from snow
High altitude
Artificial UV
Ultraviolet radiation causes skin cancer
Damage from UVR begins as soon as the sun's rays reach our skin. UVR causes many visible and invisible changes in skin cells. These include:
Skin cells include keratinocytes, which produce keratin (a protein that is the building-block in skin, hair, nails and horn) and melanocytes, which produce melanin (a brown pigment). Melanin protects the skin by absorbing UVR before it can cause any damage.
