Skin cancer occurs due to the abnormal growth of skin cells. Most forms of skin cancer occur due to excessive exposure to UV radiation. It can because of chronic sun exposure as well. Additionally, excessive use of tanning beds can trigger skin cancer. However, these are not the only causes. Skin cancer can also occur in areas which are not exposed to external agents. For example, genital areas, soles of the foot, between the toes, and inside of the mouth may also develop skin cancer. Environmental and genetic factors play a significant role in the development of this disease. All these factors can cause DNA mutation in skin cells, leading to skin cancer. The type of skin cancer depends on the skin cells affected.

Read on to know more about the different forms of skin cancer.

• Basal cell carcinoma: Basal cells are found at the bottom of the outermost layer of the skin, known as the epidermis. The function of these cells is to produce new skin cells. Under regular circumstances, the old cells die and then slough off. This process is controlled by a DNA present in the basal cell. In some cases, the DNA may undergo mutation due to chronic sun exposure, arsenic exposure, immune-suppressing medications, rare genetic diseases, and radiation therapy. The mutated DNA causes the basal cells to multiply at a faster rate. The cells continue to grow instead of dying out at the regular pace. Thus, it leads to the abnormal accumulation of basal cells. A cancerous tumor in the form of a lesion appears on the skin.
  The tumor is a pearly white or pink bump. It is translucent, and patients may be able to see tiny blood vessels through the skin. The tumors may appear on the face, ears, or neck. These may rupture and start bleeding. Scabs may form as well. In some cases, the tumors may appear black, brown, or blue. They may have a flat, scaly texture that may look slightly red. White waxy scar-like lesions may form, but this only happens in rare cases. A surgeon can easily remove this tumor through a surgical procedure. The healing period lasts from three to six weeks.
• Melanoma: Melanoma develops in the melanin-producing cells called melanocytes. Melanin is a compound that gives skin its natural complexion. Changes in the DNA of the melanocytes cause melanoma. Medical researchers are trying to find the exact cause behind these DNA mutations, but they suspect that chronic exposure to UV radiation along with environmental and genetic factors may be the main cause behind melanomas. These factors can cause a change in an existing mole as well. Patients may also experience a new pigmented growth or unusual-looking growth on the skin.
  These melanoma moles usually occur in the areas frequently exposed to the sun like the face, arms, legs, and back. In some cases, melanoma develops in the eyes, fingernail beds, palms of the hands, soles of the feet, and internal organs as well. It is relatively easy to treat melanoma in the initial stages with a biopsy. If the melanoma spreads beyond the skin, a patient may require chemotherapy, radiation therapy, biological therapy, or targeted therapy.
• Squamous cell carcinoma of the skin: This form of skin cancer develops in the squamous cells. These cells are found in the middle and outer layer of the skin. Similar to other forms of skin cancer, squamous cell carcinoma also occur due to DNA mutation. This mutation disrupts the normal cell generation and degeneration process. It causes the squamous cells to grow uncontrollably. A firm, red nodule begins to form in the affected area. In some cases, a flat sore with a scaly crust may develop. There can be warts or new sore on old scars or ulcer.
  These sores usually develop on the sun-exposed areas of the body like the lips, ears, backs of the hands, and scalp. In some cases, these sores may appear inside the mouth and on the genitals too. In most cases, doctors remove squamous cell carcinomas with the use of topical medication or minor surgeries. If the size of the tumor is large or if the skin cancer is aggressive, patients may have to undergo radiation therapy.