A doctor who stayed out the sun and dismissed a scab on her scalp as eczema was 'bewildered' when she was told it was skin cancer

• Dr. Susannah Hills noticed an irregular patch of skin behind her ear but presumed it was eczema.
• It turned out to be basal cell cancer, the most common form of skin cancer.

A doctor who presumed an irregular patch of skin on her scalp behind her left ear was eczema was later diagnosed with skin cancer.

Dr. Susannah Hills, a pediatric airway surgeon at the Columbia University Medical Center, wrote for CNN that the skin peeled and scabbed, and she used a steroid cream for eczema to no avail. After more than a year, she went to see a dermatologist for a biopsy.

Hills didn't suspect that the irregularity could be linked to cancer because it appeared in a spot that was covered by hair and hidden from the sun.

"I was bewildered," she wrote. "I thought I had been protecting myself from sun exposure so carefully."

Most skin cancers are caused by either long-term exposure to the sun or short periods of intense exposure and burning. The ultraviolet light in sunlight damages the DNA in skin cells, which can happen years before cancer develops, according to the charity Cancer Research UK.

Hills said she is conscious of protecting herself from the sun and wears sunscreen every day, even though she mainly spends time indoors. She believes that her skin cancer was caused by time spent on the beach many years ago.

Also, her mother had multiple skin cancers, which Hills said research suggests could have more than doubled her own risk of developing early on-set basal cell cancer.

Skin cancer can show up in parts of the body that are not typically exposed to the sun

After being diagnosed with basal cell cancer, Hills learned that 13% of skin cancers involve the scalp and that it can show up in unexpected places such as the eyelids, palms of the hand, and soles of the feet.

Basal cell carcinoma is the most common form of skin cancer, with an estimated 3.6 million cases diagnosed each year in the US, according to the Skin Cancer Foundation. Basal cells are found at the bottom of the epidermis — the top layer of the skin. They constantly divide to form new cells to replace the cells that wear off the skin's surface, known as squamous cells. As basal cells move up in the epidermis, they get flatter, eventually becoming squamous cells.

BCCs look different from person to person, but can show up as open sores, red patches, pink growths, shiny bumps and scars, or growths with slightly elevated and rolled edges.

BCCs grow slowly, and most are curable and cause minimal damage when caught and treated early, according to the Skin Cancer Foundation.

"It is up to each of us to develop good sun protection habits early and to learn when to seek medical care for unusual skin changes," Hills said.

She said to look out for any skin irregularities like changes in color, irregular borders of moles and freckles, skin wounds that don't seem to heal, and areas of chronic peeling or scabbing.

If you are at higher risk for developing skin cancer or have observed any of these irregularities, she advised getting a yearly exam to monitor your skin.