Basal and squamous cell carcinomas are the two most common types of skin cancer. They begin in the basal and squamous layers of the skin, respectively. Melanoma, the third most common type of skin cancer, begins in the melanocytes.

A change in your skin is the most common sign of skin cancer. This could be a new growth, a sore that doesn’t heal, or a change in a mole. Not all skin cancers look the same.

Anyone can get skin cancer, but people with certain characteristics are at greater risk A lighter natural skin color.
Skin that burns, freckles, reddens easily, or becomes painful in the sun.
Blue or green eyes.
Blond or red hair.
Certain types and a large number of moles.
A family history of skin cancer.
A personal history of skin cancer.
Older age.

Basal cell carcinoma
Melanoma
Nonmelanoma skin cancer
Squamous cell carcinoma of the skin

Examine your skin. Your doctor may look at your skin to determine whether your skin changes are likely to be skin cancer. Further testing may be needed to confirm that diagnosis.
Remove a sample of suspicious skin for testing (skin biopsy). Your doctor may remove the suspicious-looking skin for lab testing. A biopsy can determine whether you have skin cancer and, if so, what type of skin cancer you have.

Your treatment options for skin cancer and the precancerous skin lesions known as actinic keratoses will vary, depending on the size, type, depth and location of the lesions. Small skin cancers limited to the surface of the skin may not require treatment beyond an initial skin biopsy that removes the entire growth.
If additional treatment is needed, options may include:
Freezing. Your doctor may destroy actinic keratoses and some small, early skin cancers by freezing them with liquid nitrogen (cryosurgery). The dead tissue sloughs off when it thaws.
Excisional surgery. This type of treatment may be appropriate for any type of skin cancer. Your doctor cuts out (excises) the cancerous tissue and a surrounding margin of healthy skin. A wide excision — removing extra normal skin around the tumor — may be recommended in some cases.
Mohs surgery. This procedure is for larger, recurring or difficult-to-treat skin cancers, which may include both basal and squamous cell carcinomas. It's often used in areas where it's necessary to conserve as much skin as possible, such as on the nose.
During Mohs surgery, your doctor removes the skin growth layer by layer, examining each layer under the microscope, until no abnormal cells remain. This procedure allows cancerous cells to be removed without taking an excessive amount of surrounding healthy skin.
Curettage and electrodesiccation or cryotherapy. After removing most of a growth, your doctor scrapes away layers of cancer cells using a device with a circular blade (curet). An electric needle destroys any remaining cancer cells. In a variation of this procedure, liquid nitrogen can be used to freeze the base and edges of the treated area.
These simple, quick procedures may be used to treat basal cell cancers or thin squamous cell cancers.
Radiation therapy. Radiation therapy uses high-powered energy beams, such as X-rays, to kill cancer cells. Radiation therapy may be an option when cancer can't be completely removed during surgery.
Chemotherapy. In chemotherapy, drugs are used to kill cancer cells. For cancers limited to the top layer of skin, creams or lotions containing anti-cancer agents may be applied directly to the skin. Systemic chemotherapy can be used to treat skin cancers that have spread to other parts of the body.
Photodynamic therapy. This treatment destroys skin cancer cells with a combination of laser light and drugs that makes cancer cells sensitive to light.
Biological therapy. Biological therapy uses your body's immune system to kill cancer cells.

here is no sure way to prevent all basal and squamous cell skin cancers. Some risk factors such as your age, sex, race, and family history can’t be controlled. But there are things you can do that could lower your risk of getting these and other skin cancers.
Limit your exposure to ultraviolet (UV) rays
The most important way to lower your risk of basal and squamous cell skin cancers is to limit your exposure to UV rays. Practice sun safety when you are outdoors.
Look for shade
Simply staying in the shade is one of the best ways to limit your UV exposure.