Topic Overview
Most skin bumps, spots, growths, and
moles are harmless. Colored skin spots, also called
pigmented lesions (such as freckles, moles, or flesh-colored skin spots), or
growths (such as
warts or
skin tags) may be present at birth or develop as the
skin ages.
Most skin spots on babies will go away without treatment within a
few months.
Birthmarks are colored marks on the skin that are
present at birth or develop shortly after birth. They can be many different
sizes, shapes, and colors, including brown, tan, black, blue, pink, white, red,
or purple. Some birthmarks appear on the surface of the skin, some are raised
above the surface of the skin, and some occur under the skin. Most birthmarks
are harmless and do not need treatment. Many birthmarks change, grow, shrink,
or disappear. There are many types of birthmarks, and some are more common than
others. For more information, see the topic
Birthmarks.
Cause of skin changes
Acne is a common skin change that occurs during the
teen years and may last into adulthood. Acne may be mild, with just a few
blackheads (comedones), or severe, with large and painful pimples deep under
the skin (cystic lesions). It may be present on the chest and
back as well as on the face and neck. Boys often have more severe outbreaks of
acne than girls. Many girls have acne before their periods that occurs because
of changes in
hormone levels. For more information, see the topic
Acne Vulgaris.
During pregnancy, dark patches may develop on a woman's face.
This is known as the "mask of pregnancy," or chloasma, and it usually fades
after delivery. The cause of chloasma is not totally understood, although it is
thought that increased levels of pregnancy hormones cause the pigment-producing
cells in the skin (melanocytes) to produce more pigment. You can reduce skin
pigment changes during pregnancy by using sunscreen and staying out of the
sun.
Actinic keratosis is a type of colored skin spot that
is caused by too much sun exposure. Although it is not a skin cancer, it may
mean that you have an increased chance of getting skin cancer, such as
squamous cell skin cancer.
You may have an
allergic reaction to a
medicine that causes a skin change, or develop a skin
reaction when you are out in the sun while you are taking a medicine (this is
called photosensitivity). Rashes, hives, and itching may develop, and in some
cases may spread to areas of your skin that were not exposed to the sun
(photoallergy). For more information, see the topic
Allergic Reaction.
Skin changes can also be caused by:
Common skin changes
Some common skin growths include:
- Moles. Most people have
between 10 and 40 moles. You may continue to form new moles until you are in
your 40s. Moles may change over time. They can gradually get bigger, develop a
hair, become more raised, get lighter in color, fade away, or fall
off.
- Skin tags are harmless growths that
appear in the skin folds on the neck, under the arms, under the breasts, or in
the groin. They begin as small fleshy brown spots and may grow a small stalk.
Skin tags never turn into skin cancer.
- Seborrheic
keratoses are harmless skin growths that are found most often on the
chest or back, occasionally on the scalp, face, or neck, and are less common
below the waist. They begin as slightly raised tan spots that develop a crusty
appearance like that of a wart. Seborrheic keratoses never turn into skin
cancer. For more information, see the topic
Seborrheic Keratosis.
Treatment of a skin change depends on what is causing the skin
change and what other symptoms you are having. Moles, skin tags, and other
growths can be removed if they become irritated, bleed, or cause
embarrassment.
Skin cancer
While most skin changes are normal and occur with aging, some may
be caused by cancer.
Skin cancer may start as a growth or mole, a
change in a growth or mole, a sore that does not heal,
or irritation of the skin. It is the most common form of cancer in North
America.
Skin cancer destroys skin cells and tissues and can spread
(metastasize) to other parts of the body. The three most common types of skin
cancer are
basal cell cancer,
squamous cell cancer, and
melanoma. See a picture of the
ABCDs of
melanoma
.
Causes of skin cancer include:
- Overexposure to the sun, such as a severe,
blistering sunburn during childhood.
- Years of overexposure to the
sun as an adult.
- The use of tanning beds or sunlamps. UV rays from
a tanning bed may actually be more harmful than the sun because they are more
intense.
- Repeated exposure to X-rays, chemicals, and radioactive
substances.
- Radiation treatments for conditions such as
eczema,
psoriasis, or
acne.
Kaposi's sarcoma is a serious form of skin cancer. It
is often found in people who have an
impaired immune system, such as people with
AIDS. Blue-red raised bumps (nodules) may appear on
the face, arms, and trunk and inside the mouth.
Early detection and treatment of skin cancer can help prevent
problems. Treatment depends on the type and location of the growth and how
advanced it is when it is diagnosed. Surgery to remove the growth will help
determine what treatment will be needed. For more information, see the topics
Skin Cancer, Melanoma or
Skin
Cancer, Nonmelanoma.
Review the Check Your Symptoms section to determine if and when to
see a doctor.