Basal cell carcinoma usually occurs on sun-exposed areas such as the neck or face. It can appear as a pearly or waxy bump, a flat, flesh-colored or brown scar-like lesion, or a bleeding or scabbing sore that heals and returns.
Squamous cell carcinoma primarily occurs on sun-exposed areas like the face, ears, and hands. It may present as a firm, red nodule or a flat lesion with a scaly, crusted surface.
Melanoma, the most serious type of skin cancer, can develop anywhere on the body. It can arise in otherwise normal skin or in an existing mole that becomes cancerous. Melanoma often appears on the face or trunk in men and on the lower legs in women. Signs of melanoma include a large brownish spot with darker speckles, a changing mole in color, size, or feel, a small lesion with an irregular border and portions that appear red, pink, white, blue, or blue-black, a painful lesion that itches or burns, and dark lesions on the palms, soles, fingertips, toes, or mucous membranes.
Other less common types of skin cancer include Kaposi sarcoma, which develops in the skin’s blood vessels and causes red or purple patches on the skin or mucous membranes, and Merkel cell carcinoma, which causes firm, shiny nodules on or beneath the skin and is commonly found on the head, neck, and trunk. Sebaceous gland carcinoma, originating in the oil glands of the skin, is another uncommon and aggressive type of skin cancer.
The main layers of the skin affected by skin cancer are the epidermis (upper or outer layer) and the dermis (lower or inner layer). Squamous cells, basal cells, and melanocytes are the three types of cells found in the epidermis. Basal and squamous cell carcinomas originate in the basal and squamous layers of the skin, respectively, while melanoma begins in the melanocytes. Melanoma is the most dangerous type of skin cancer because of its tendency to spread to other parts of the body.
Excessive exposure to ultraviolet (UV) radiation from the sun, tanning beds, or sunlamps is a primary cause of skin cancer. Over time, UV damage can lead to changes in skin texture, premature aging, and skin cancer. Skin cancers can also develop in areas of the skin not typically exposed to sunlight, suggesting that other factors may contribute to the risk, such as having a weakened immune system.
Regularly checking the skin for suspicious changes and seeking early detection through self-examinations and medical screenings are important for identifying skin cancer at its earliest stages. Early detection provides the greatest chance for successful treatment. It is also crucial to reduce the risk of skin cancer by limiting or avoiding exposure to UV radiation and using protective measures such as sunscreen, protective clothing, and seeking shade when the sun is strongest.