You should get a professional skin check if you notice any mole or spot that has changed in size, shape, or color over the past few weeks or months, or if you have a sore that won’t heal. Beyond those immediate red flags, a monthly self-exam at home and periodic visits to a dermatologist based on your risk level will catch most skin cancers early, when they’re easiest to treat.
Warning Signs That Call for a Prompt Visit
Certain changes on your skin shouldn’t wait for a routine appointment. The most widely used framework for spotting suspicious moles is the ABCDE checklist:
- Asymmetry: One half of the mole doesn’t match the other.
- Border: The edges are ragged, notched, or blurred, and pigment may spread into the surrounding skin.
- Color: The mole has uneven shading, with a mix of black, brown, tan, white, gray, red, pink, or blue.
- Diameter: The spot is larger than about 6 millimeters (roughly the size of a pencil eraser), though melanomas can sometimes be smaller.
- Evolving: The mole has visibly changed over recent weeks or months.
You don’t need all five features to be concerned. Any single one, especially a mole that’s evolving, is enough reason to book an appointment.
There’s also a useful gut-check method sometimes called the “ugly duckling sign.” If one spot on your body simply looks different from all your other moles, that outlier is the most suspect. Most of your moles tend to resemble each other. The one that breaks the pattern, the funny-looking one, deserves professional evaluation even if it doesn’t neatly tick every ABCDE box.
Signs Beyond Suspicious Moles
Melanoma gets the most attention, but the two more common types of skin cancer look quite different. Basal cell carcinoma often appears as a shiny, slightly translucent bump that can look pearly white or pink. It may also show up as a flat, scar-like area or a sore that bleeds, scabs over, and then reopens without fully healing. If you have a wound that cycles like this for more than a few weeks, get it checked.
Squamous cell carcinoma and its precursor, actinic keratosis, tend to present as rough, scaly patches. Early squamous cell lesions can appear as a large reddish, crusted patch, sometimes bigger than an inch across. These usually develop on sun-exposed areas like the face, ears, hands, and forearms. Any persistent scaly or crusty spot that doesn’t resolve on its own warrants a look from your doctor.
Skin Cancer on Darker Skin Tones
One type of melanoma, acral lentiginous melanoma, develops in places most people don’t think to check: the palms, soles of the feet, and under the nails. It’s the most common form of melanoma diagnosed in people with darker skin, and it occurs on areas that get little sun exposure. On the palms and soles, these lesions often appear as dark brown or black patches. Under a nail, they typically show up as a long pigmented streak that may extend to the skin around the nail or cause the nail to split. Some lesions are pink or red rather than dark, making them easy to overlook.
The standard ABCDE criteria are less reliable for this type. A different acronym, CUBED, has been proposed for spots on hands, feet, and nails: colored lesions that are bleeding, have an uncertain diagnosis, are enlarged, or deteriorate with delayed healing. People with pigmented skin frequently receive their diagnosis at a more advanced stage, largely because these signs get missed early. Checking your palms, soles, toes, and nails during your monthly self-exam is essential regardless of skin tone.
How Often to Do a Self-Exam
The Skin Cancer Foundation recommends a head-to-toe self-check once a month. You’re looking for anything new, anything that’s changed, and anything that doesn’t heal. The areas people miss most often are the scalp, the backs of the ears, between the toes, the soles of the feet, and the genitals. Use a hand mirror or ask a partner to help with spots you can’t see easily.
Taking photos of moles you want to track can be surprisingly helpful. A mole that looks “maybe different” is much easier to judge when you can compare it side by side with a photo from two months ago. If you have many moles, this is one of the best things you can do between professional appointments.
When to Schedule Routine Screenings
Screening guidelines vary depending on where you fall on the risk spectrum, and there’s no single universal rule. The U.S. Preventive Services Task Force currently says the evidence is insufficient to recommend for or against routine skin exams by a clinician for the general population. That doesn’t mean screening is harmful. It means large-scale studies haven’t yet proven a clear population-wide benefit, so the decision is individual.
In practice, most cancer organizations recommend periodic skin checks as part of regular health exams for adults over 20. Germany’s national screening program offers a full-body skin check to adults 35 and older every two years, which gives a reasonable baseline for average-risk people: every one to two years once you’re in your mid-thirties or older.
If you’re at higher risk, the timeline tightens considerably. High-risk factors include:
- A family history of melanoma (about 10% of melanoma patients have one)
- A large number of moles, or five or more unusual-looking moles
- Fair skin, light eyes, or red hair
- A history of blistering sunburns or frequent tanning
- A weakened immune system
- A personal history of any skin cancer
If any of those apply to you, guidelines from dermatology organizations in Australia, the Netherlands, and the U.S. converge on professional skin exams every 6 to 12 months. People with a prior melanoma or many atypical moles are often advised to do self-exams every three months, with clinical exams every six months.
What Happens During a Professional Skin Check
A clinical skin exam is quick and noninvasive. You’ll change into a gown, and the dermatologist will systematically examine your skin from head to toe, including your scalp, between your fingers and toes, and other easy-to-miss spots. The whole process usually takes 10 to 15 minutes.
If anything looks questionable, your doctor may use a dermatoscope, a handheld device that combines a magnifying lens with a light to reveal structures beneath the skin’s surface that aren’t visible to the naked eye. Spots that look unusual but don’t yet need removal are often photographed so there’s a baseline for comparison at your next visit. If a spot does look suspicious enough, a biopsy (removing a small sample of skin) is typically done the same day. Results usually come back within a week or two.
There’s no special preparation needed. The main thing is to arrive without nail polish on your fingers and toes so the doctor can check under your nails, and to mention any spots that have been bothering you so they don’t get overlooked.