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Five things you should know about skin lesions

What are skin lesions, and when should you see a doctor about one? University of Minnesota Health Dermatologist Lori Fiessinger, MD, shares her expertise and offers tips.
University of Minnesota Health Dermatologist Lori Fiessinger, MD, sees a wide variety of patients, including general dermatology, cosmetic dermatology and high-risk skin cancer patients.

The phrase “skin lesion” covers a wide range of color changes, lumps and bumps, patches, rashes and other things on or under the skin. Freckles, moles, areas of itchy, dry skin and many other marks all qualify as skin lesions. Many are normal, but a few can be deadly.

University of Minnesota Health Dermatologist Lori Fiessinger, MD, shared five things you should know about skin lesions.

Not all the brown spots on your skin are moles.

Moles are collections of melanocytes—a type of pigment-producing cell. They can be flat or elevated, brown, black or pink, and they often appear early in life. Moles generally stop appearing after age 40. Over time, they have the potential to develop into skin cancer.

But not all dark spots on your skin are moles, Fiessinger noted. They can also be harmless freckles or sun spots—which are flat spots that occur in sun-exposed areas due to UV exposure. Brown spots that occur after age 40 are often seborrheic keratosis, also known as wisdom or age spots. They are elevated brown bumps that can have a waxy or crusty texture. Though their appearance may be concerning, they are not made up of melanocytes, so they do not carry a risk of skin cancer.

Scar tissue can also appear as a brown spot or bump on the skin. A dermatofibroma is a flat or slightly elevated bump with a white to purple scar tissue center surrounded by a brown rim. Dermatofibromas are benign.

Our team of board-certified dermatologists with University of Minnesota Health provide comprehensive, coordinated care for conditions ranging from acne to skin cancer. Learn more about our care.

When it comes to moles, remember “ABCDE.”

It is normal to develop moles in childhood and young adulthood. Because moles have the capacity to develop into skin cancer, Fiessinger recommends once-a-month skin self-examinations. During these skin checks, each individual should examine his or her existing moles and scan for new or changing moles. To know what to look for, remember ABCDE:
  • Asymmetry – Divide the mole in half. If one side looks different than the other, that could be a cause for concern.
  • Borders – Moles should have a defined cutoff at the edges. Moles that appear to trail off into the skin without a distinct edge should be examined by a dermatologist.
  • Color – If a single mole contains more than two colors—including different shades of brown, black, blue, or pink—it may need to be evaluated.
  • Diameter – If the mole is bigger than the width of the pencil eraser (about 6mm), it needs to be checked.
  • Evolving –Changes to the shape or appearance of an existing mole are a red flag. So is the development of a new mole after age 40.

There is more than one type of skin cancer.

The ABCDE standards were designed with melanoma in mind, but other types of skin cancer are far more common, including basal cell carcinoma and squamous cell carcinoma. Basal cell carcinoma can manifest on the skin in a variety of different ways. It can appear as an open sore; a reddish, irritated area; a pale, scar-like patch or in other forms. Squamous cell carcinomas are more likely to appear as rough, scaly red patches similar in appearance to eczema. They can also be wart-like in character, or present as open sores that fail to heal. Anything that grows rapidly is also a red flag, whether or not it fits these general skin cancer guidelines.

University of Minnesota Health offers multidisciplinary for all types of skin cancers. Learn more about our skin cancer care.

Rashes are skin lesions, too. And the most common rash culprit may surprise you.

A rash is composed of skin lesions that may cover a small or large area of skin. Rashes can happen for lots of reasons, but one of the most common causes is a reaction to personal care products like creams, lotions, soaps and shampoos. The fragrances and other substances in these products can often irritate the skin, Fiessinger said. Clothing-related products like detergents and fabric softeners also fall into this category. Even though these products are not applied directly to the skin, the chemicals contained in them can linger in the clothing that you wear.

If you think a personal care product may be causing a rash, Fiessinger recommends switching from your current product to gentler, fragrance-free version. People can develop sensitivities to products at any time, even if you have been using the same product for years without experiencing any negative effects. In addition, companies are always changing ingredients and formulations of their products, so there may be a new substance in your go-to product that you’re reacting to.

If you switch products and the rash doesn’t go away, then it’s time to visit a dermatologist to determine the cause.

Allergies may also cause rashes skin irritation. Our Dermato-Allergologist Paul Bigliardi, MD, is an expert in the diagnosis and treatment of allergy-related skin reactions. Read more.

How often should you get a skin exam? It depends.

There aren’t one-size-fits-all guidelines for when people should follow up with a dermatologist. In general, it’s smart to go in for an appointment any time you see something on your skin that concerns you. At that initial appointment, the dermatologist will talk with you about your family history and assess your skin cancer risk. This will help your doctor determine when you should come back for your next screening appointment. There’s no substitute for a dermatologist’s trained eye, and catching problems early can make all the difference.