Skin cancer is common. The American Academy of Dermatology (AAD) estimates that about 9,500 people in the US are diagnosed with it every day. It is not one disease but several, and the main types do far better when they are found early. That is what a skin check is for.
The main types
Basal cell carcinoma is the most common type. It often looks like a round, pearly or shiny bump, or a raised, scaly patch, usually on the head, neck, chest or upper back. It grows slowly and rarely spreads beyond the skin, but it still needs treatment so it does not grow deeper.
Squamous cell carcinoma often looks like a rough, scaly patch, a firm dome-shaped growth, or a sore that does not heal, usually on the head, neck, arms or shins. It is the most common type in people with darker skin tones. It is highly treatable when caught early.
Melanoma is the most serious type. It can start in a mole you already have or appear as a new dark spot that looks different from your other moles. It can show up on skin that gets little or no sun, and anyone can get it, whatever their skin tone. Found early and treated properly, the outcome can be good.
Rarer types include Merkel cell carcinoma, sebaceous carcinoma (often on an eyelid, where it can look like a slow stye) and dermatofibrosarcoma protuberans.
The ABCDE warning signs
Dermatologists use the ABCDEs to describe a spot that needs a look:
- Asymmetry: one half is unlike the other.
- Border: the edge is irregular, scalloped or poorly defined.
- Color: the color varies from one area to the next.
- Diameter: usually larger than 6 millimeters, about the size of a pencil eraser, though melanomas can be smaller.
- Evolving: the spot looks different from the rest, or it is changing in size, shape or color.
Who is at higher risk
The CDC lists lighter natural skin, skin that burns, freckles or reddens easily, blue or green eyes, blond or red hair, certain types or a large number of moles, a history of sunburns or tanning, a family or personal history of skin cancer, and older age. Having none of these does not mean no risk.
When to see a dermatologist
The AAD advises seeing a dermatologist right away for any spot with the ABCDE signs. It also advises an appointment for a spot that is new, looks different from your others, or is changing, itching or bleeding. A sore that does not heal belongs on that list too. A dermatologist’s exam, and sometimes a biopsy, is how a spot gets identified.
What a skin check involves
The Skin Cancer Foundation describes the visit plainly. You change into a gown and the dermatologist checks your skin head to toe, including the scalp, back, buttocks, behind the ears and between the toes. For someone with no history of atypical moles or skin cancer, it often takes about 10 minutes. The dermatologist may look at spots through a dermatoscope, a handheld magnifier that shows the layers just under the surface.
If a spot looks suspicious, the dermatologist may do a biopsy: removing part or all of it and sending it to a lab. If the result is cancer, they explain the type and the options.
To prepare, check your own skin first and take phone photos of anything that has changed. Remove nail polish and makeup, and wear your hair loose so the scalp can be seen.
How dermatologists treat it
The plan depends on the type, how deep it has grown, where it is, and your health and age. For basal cell carcinoma, the AAD lists these categories:
- Surgical excision, cutting out the cancer with a margin of skin. This is the most common treatment.
- Mohs surgery, which removes the cancer one thin layer at a time and checks each layer under a microscope until no cancer remains. The AAD says it has the highest cure rate of all skin cancer treatments, though it is not necessary for every case.
- Scraping and heat (electrodesiccation and curettage) for low-risk tumors.
- Prescription creams or light-based treatment (photodynamic therapy) for some superficial or low-risk tumors.
- Freezing, radiation or watchful monitoring in specific situations, and medicines that work through the whole body for advanced disease.
The plan for squamous cell carcinoma, melanoma and the rarer types depends on the biopsy result, and your dermatologist explains it.
Prevention
The CDC’s advice is to protect your skin from the sun and avoid tanning. The AAD adds regular self-checks, so you notice a new or changing spot early.
How to choose a dermatologist
Ask whether the visit is a full-body exam or a check of one spot. Ask whether biopsies can be done at the same visit and how results are shared. If you have been diagnosed and Mohs surgery is on the table, ask who performs it. The Skin Cancer Foundation describes Mohs surgeons as trained to remove the tissue, read it under the microscope and repair the wound, and points patients to fellowship-trained Mohs surgeons. Check with your insurer whether you need a referral first and what the visit will cost under your plan.
The city list below shows dermatologists who name skin cancer on their own websites.