Moles come in a wide variety of colors, shapes and sizes. Moles are usually harmless collections of pigmented cells called melanocytes on your skin. They can appear alone or in multiples. Moles are also called nevi; a single mole is a nevus. Most moles are present on the torso, but they are also commonly found on your face, arms and legs. Moles can be present in more obscure locations as well - including on your scalp, under your nails, in your armpits and around your genitals.

Most of us have from 10 to 40 moles. The number of moles you have may constantly change. New moles may appear up through your midadult years, but most appear by age 20. Some moles disappear with advancing age.

It's especially important to become familiar with the moles on your skin because, in rare cases, they can become cancerous. Monitoring your moles and other pigmented patches, such as freckles and age or liver spots, is an important first step in reducing your risk of skin cancer - especially malignant melanoma, which may begin in or near a mole or other dark spot on the skin. Melanoma also can arise in areas of normal pigmentation.

• Melanoma

Signs and symptoms

Moles come in a wide variety of colors, shapes and sizes. They can be flesh-colored, brown, blue or black spots that vary in shape from oval to round. They can be as small as a pinhead or large enough to cover an entire limb. Moles that are larger than 8 inches in diameter and present at birth are a special problem. They may need to be removed to avoid the risk of cancer.

The surface of a mole can be smooth or wrinkled, flat or raised. Over your lifetime, some of your moles are likely to change. With exposure to sun, they may darken. They also may start out flat and brown in color and later become slightly raised and lighter in color. Some may become raised enough that they form a small stalk and are eventually rubbed off. Others may just disappear.

There are certain times in your life when moles may be more apt to change. During adolescence, for example, moles may darken and become larger. During pregnancy, women may develop numerous and darker moles.

Causes

Moles have no known purpose, and scientists don't know why they develop. Most moles are harmless and don't require special care. If a mole is irritated or unattractive, however, you may want to have it removed. All moles that are removed should be examined under a microscope because doctors can't always tell if moles are precancerous or cancerous just by the way they look on your skin. In all cases, you need to monitor your own moles for changes in size, shape, color, texture and sensation that may indicate a problem.

Risk factors

Several types of moles have a higher than average risk of becoming cancerous. They include:

• Large moles present at birth. Large moles that are present at birth are called congenital nevi or giant hairy nevi. These moles may increase your risk of malignant melanoma, a deadly form of skin cancer. In general, moles that are more than the size of an adult open palm pose the greatest risk. Have your doctor examine any mole that was present at birth and is palm-sized or larger.

• Moles that run in families. Moles that are larger than average — which is about 1/4 inch (6 millimeters) or the diameter of a pencil eraser — and irregular in shape are known as atypical (dysplastic) nevi. These moles tend to be hereditary. They are frequently described as looking like fried eggs because they usually have dark brown centers and lighter, uneven borders. Overall, they may look red or tan. If you have dysplastic nevi, you have a greater risk of developing malignant melanoma.

• Numerous moles. If you have many moles larger than a pencil eraser, you are at greater risk of developing melanoma.

If you're fair-skinned, blue-eyed, freckled and have light-colored hair, you're at particularly high risk of skin cancer of all kinds, not just melanoma. Avoid overexposure to sunlight and protect your skin from sunburn and blistering. The majority of lifetime sun exposure for most people occurs before age 20. Be sure to begin sun protection habits in early childhood for your children and grandchildren, and maintain these habits yourself at all ages. Avoid strong sun exposure, wear protective clothing and use sunscreens.

• Melanoma

• Skin cancer

Moles > 1 > 2 > 3 > 4 

Related Site:

• Corns and calluses

• Nail fungal infection

• Ingrown toenails

• Moles

• Skin cancer

• Psoriasis

• Baldness

• Sweating and body odor

• Rosacea

• Hives and angiedema

• Athlete's foot

• Dermatomyositis

• Dermatitis/Eczema

• Cold sore

• Scleroderma

• Lice

• Common warts

• Melanoma

• Cellulitis

• Scabies

• Anal itch

• Dandruff

• Impetigo

• Boils and carbuncles

• Psoriatic arthritis

• Jock itch

• Plantar warts

• Folliculitis

Treatments