Skin cancer is one of the most common types of cancer worldwide, caused by the abnormal growth of skin cells. It usually develops in areas that are exposed to sunlight, such as the face, scalp, arms, and neck, but it can also appear on parts of the body rarely exposed to the sun. There are three main types: basal cell carcinoma, squamous cell carcinoma, and melanoma, with melanoma being the most aggressive and potentially life-threatening if not detected early. The condition is strongly linked to excessive ultraviolet (UV) radiation from the sun or tanning beds, though other factors like fair skin, family history, weakened immunity, frequent sunburns, and the presence of abnormal moles also increase risk.

Early signs of skin cancer often include new growths, sores that do not heal, or changes in existing moles such as irregular borders, uneven color, or increase in size. In melanoma, unusual dark spots may also appear on nails, palms, or soles. Diagnosis usually involves a thorough skin examination by a specialist, dermoscopy, and a biopsy to confirm the type of cancer. Advanced imaging such as CT, MRI, or PET scans may be required if doctors suspect the cancer has spread.