Skin cancer is a disease in which abnormal cells grow in the skin and form tumors. It usually develops in areas of skin exposed to sunlight, but it can occur anywhere on the body.
Skin cancer is one of the most common types of cancer. Many skin cancers grow slowly and can be treated successfully when found early.
This guide explains what skin cancer is, skin cancer symptoms, types of skin cancer, causes, treatment, and prevention.
This information is educational only and not medical advice.
What Is Skin Cancer
Skin cancer begins when skin cells develop DNA damage that allows them to grow uncontrollably and avoid normal cell death.
As abnormal cells multiply, they form growths or lesions on the skin.
Most skin cancers develop in the outer layer of skin called the epidermis.
Skin cancer can spread to deeper tissue and other organs if not treated.
Skin cancer often develops slowly and is easier to treat when detected early.
Types of Skin Cancer
There are three main types of skin cancer.
Basal Cell Carcinoma
Basal cell carcinoma is the most common type of skin cancer.
It usually develops in areas exposed to the sun such as:
face
ears
neck
scalp
arms
Basal cell carcinoma usually grows slowly and rarely spreads to other parts of the body.
Symptoms may include:
pearly bumps
shiny patches
sores that do not heal
bleeding spots
Squamous Cell Carcinoma
Squamous cell carcinoma is the second most common type of skin cancer.
It develops in the outer layers of skin.
It may grow faster than basal cell carcinoma.
Symptoms may include:
rough scaly patches
raised growths
sores that do not heal
crusted areas
Squamous cell carcinoma can spread if untreated.
Melanoma
Melanoma is less common but more dangerous.
Melanoma begins in pigment-producing cells called melanocytes.
Melanoma is more likely to spread to other parts of the body.
Melanoma may appear as:
dark spots
irregular moles
changing moles
Early detection is very important.
Skin Cancer Symptoms
Skin cancer symptoms usually appear as visible changes on the skin.
Common skin cancer symptoms include:
new skin growth
mole changes
sores that do not heal
bleeding spots
scaly patches
lumps on the skin
Any new or changing skin lesion should be evaluated.
Warning Signs of Skin Cancer
Important warning signs include:
a mole that changes size
a mole that changes color
uneven borders
itching or bleeding
sores that do not heal
These changes may develop slowly.
The ABCDE Rule for Melanoma
The ABCDE rule helps identify melanoma.
A — Asymmetry
One half of the mole looks different from the other half.
B — Border
Edges may look irregular or uneven.
C — Color
Color may vary within the mole.
Colors may include:
brown
black
red
white
blue
D — Diameter
Moles larger than about 6 mm may need evaluation.
E — Evolving
Changes over time are important warning signs.
Changing moles should be evaluated.
Causes and Risk Factors
Skin cancer develops from DNA damage combined with environmental factors.
Sun Exposure
Ultraviolet radiation from sunlight is the leading cause of skin cancer.
Repeated sun exposure damages skin DNA.
Tanning Beds
Artificial tanning devices increase risk.
Fair Skin
People with lighter skin have higher risk.
Family History
Some people inherit increased risk.
Age
Risk increases with age.
Weakened Immune System
Reduced immune function increases risk.
How Skin Cancer Is Diagnosed
Diagnosis may include:
skin examination
dermoscopy
biopsy
A biopsy confirms skin cancer.
Skin Cancer Treatment
Treatment depends on type and stage.
Surgical Removal
Most skin cancers are removed surgically.
Early removal often cures skin cancer.
Cryotherapy
Freezing destroys abnormal tissue.
Radiation Therapy
Radiation may be used in some cases.
Immunotherapy
Used for advanced melanoma.
Targeted Therapy
Used for certain melanomas.
Skin Cancer Prevention
Risk can be reduced by:
using sunscreen
avoiding excessive sun
wearing protective clothing
avoiding tanning beds
checking skin regularly
Sun protection reduces risk.
When to Seek Medical Evaluation
Medical evaluation is important if you notice:
new moles
changing moles
sores that do not heal
bleeding spots
unusual skin growths
Early detection improves outcomes.
Medical References
National Cancer Institute
https://www.cancer.gov/types/skin
American Cancer Society
https://www.cancer.org/cancer/skin-cancer.html
Mayo Clinic
https://www.mayoclinic.org/diseases-conditions/skin-cancer
CDC
https://www.cdc.gov/cancer/skin
