Basal cell carcinomas are the most common but least dangerous type of skin cancer. It accounts for about 75% of skin cancers. They grow slowly over months to years but if left untreated, a deep (rodent) ulcer may form. Fortunately, they very rarely spread to other parts of the body. If you have one basal cell carcinoma, you may have others; either at the same time or in later years. Basal cell carcinomas are most commonly found on the face, neck and upper trunk. They may appear as a lump or scaly area and are pale, pearly or red in colour. They may have blood vessels on the surface.

Squamous cell carcinomas are more dangerous than basal cell carcinomas. It accounts for about 20% of skin cancers.They usually grow over a period of weeks to months. These cancers may spread to other parts of the body (metastasis) if not treated promptly. Squamous cell carcinomas appear on areas of skin most often exposed to the sun. They have scaling, red areas which may bleed easily and ulcerate, looking like an unhealing sore. These common skin cancers generally occur in people over the age of 40. However, basal cell carcinoma can occur in younger adults. The major cause of these skin cancers is sun exposure over many years.

Melanoma is the rarest but most dangerous skin cancer. It accounts for about 5% of skin cancers.It is often a fast growing cancer which if left untreated, can spread quickly to other parts of the body to form secondary cancers or metastases. Melanomas can appear anywhere on the body, not only in areas that get a lot of sun. The first sign of a melanoma is usually a change in a freckle or mole, or the appearance of a new spot on normal skin. Changes are normally seen over a period of several weeks to months, not over several days. The changes are in size, shape or colour. Melanoma can occur from adolescence onwards and is most common between 30 and 50 years of age. In rare instances it may develop in children.