For general education, not medical advice. This guide can’t diagnose you or replace care from your own clinician. If you’re worried about a spot or symptom, see a board-certified dermatologist.
A skin self-exam is a simple, regular check of your own skin for new or changing spots. The goal is not to diagnose anything yourself. The goal is to notice a spot worth showing a doctor, so a skin cancer can be found while it is small and easy to treat. This guide explains how to check your skin with the ABCDE rule and the ugly duckling sign, what a self-exam can miss, and gives honest answers about the phone apps people ask about.
Key points
- Knowing your own skin helps you find a new or changing spot early, when treatment is simpler.1
- The two tools to use are the ABCDE rule and the ugly duckling sign, the spot that looks different from your others.23
- A self-exam is one layer of early detection, not the whole plan. It does not replace a professional skin check, and self-detected spots are more often missed on the back.4
What a skin self-exam is
A skin self-exam means looking over your whole body every so often to learn what is normal for you, then watching for anything that is new, changing, or simply does not fit. The single most useful thing you can notice is change. A spot that grows, darkens, changes shape, itches, or bleeds is worth a closer look.5
To check well, use good light and a full-length mirror, and use a hand mirror for your back and scalp. Look everywhere, including places the sun rarely reaches: your scalp, behind your ears, between your toes, the soles of your feet, and under your nails. Many spots are easy to see in a mirror, but the back is a common blind spot, which is one reason a partner helps.4
How to check: ABCDE and the ugly duckling
Two simple guides cover most of what to look for.
The ABCDE rule lists the warning signs of melanoma:
- A is for Asymmetry. One half does not match the other.
- B is for Border. The edges are uneven, notched, or blurred.
- C is for Color. More than one color, or an uneven mix of brown, black, red, white, or blue.
- D is for Diameter. Larger than a pencil eraser, about 6 millimeters, though some melanomas are smaller.
- E is for Evolving. Any change in size, shape, color, or feel. The letter E was added because change is such a strong warning sign.25
The ugly duckling sign is even simpler. Most of your moles tend to look alike. The one that stands out from the rest, the odd one, is the one to show a doctor. In studies, melanomas usually stood out as the different spot when compared with a person's other moles.36
What the research shows about self-exams
Here is each part of a self-exam and how well it is supported, graded on the same scale used across this library.
Knowing your own skin and watching for change can help you find a melanoma earlier, when it is thinner and easier to treat. But no randomized trial has shown that checking your own skin lowers the chance of dying from melanoma. One early study suggested a benefit, and a 20-year follow-up of the same people did not confirm it. Self-checks also miss more on hard-to-see areas like the back, so they work best alongside professional skin exams.
ABCDE is a simple guide for what to watch: Asymmetry, Border that is uneven, Color that varies, Diameter larger than a pencil eraser, and Evolving (any change). Change is the strongest single warning sign. The rule is a good starting point, but it can miss melanomas that are not the classic flat, dark, lopsided type, such as fast-growing bumps, skin-colored or pink spots, and those on the palms, soles, or nails.
The idea is simple: the spot that looks different from your other moles is the one to show a doctor. In studies, melanomas usually stood out as the odd one when compared with a person’s other spots. It is a useful partner to the ABCDE rule, especially for people with many moles.
A partner can look at the places you cannot easily see, like your back, scalp, and the backs of your legs. In trials, people who learned to check with a partner examined more of their body than people who learned alone.
Taking a baseline photo and comparing it over time helps you and your doctor notice change, which is the strongest warning sign. It is a way to track a spot, not a way to diagnose it, so a photo cannot tell you a spot is safe.
Whole-body prevention, separate from the spot treatments above. “No effect” means good trials found no benefit. Every source is PubMed-verified; not medical advice.
A few honest notes on this table. Finding skin cancer earlier, when it is thinner, is clearly tied to better outcomes.1 What is not proven is that checking your own skin lowers the chance of dying from melanoma. One early study suggested a large benefit, but the authors said it needed to be repeated, and a 20-year follow-up of the same people did not confirm it.78 A review of the few trials that exist could neither prove nor rule out a benefit from skin checks.9 So a self-exam is best seen as useful skin awareness that works alongside professional exams, not as a test that stands on its own. It also misses things. Self-detected melanomas are more often thicker than those a doctor finds, especially on the back, which is hard to see.104
Other options patients ask about
People often arrive having downloaded an app or planning to keep an eye on a spot on their own. Here are the honest answers.
- "Can a phone app check my mole for me?" Not reliably. When researchers tested mole-check apps, the results were poor and uneven. One app missed every melanoma it was shown, and the apps as a group could not be relied on to catch all skin cancers.1112 A review of dozens of these apps found that none had been properly tested for accuracy.13 An app may remind you to look, but it cannot tell you a spot is safe. If a spot worries you, see a clinician, whatever an app says.
- "Should I track my own photos?" Yes, as a memory aid. Comparing photos of a spot over time helps you and your doctor notice change, the strongest warning sign.14 Just remember a photo is a way to track a spot, not a way to diagnose it.
- "Can I remove a worrying spot myself?" No. At-home mole-removal pens, creams, and burning kits do nothing to find skin cancer, and they destroy the very tissue a doctor needs to tell whether a spot was harmless. Checking and removing are different things, and removal belongs in a clinic.
- "Can I just ask an online symptom checker?" General symptom-checker tools and chatbots are not tested to rule out skin cancer. Treat a reassuring answer as meaningless for a spot that is new, changing, or different.
What a self-exam can miss
The ABCDE rule and the ugly duckling sign are good for the common type of melanoma, the flat, dark, uneven kind. They are weaker for other kinds, so it helps to know the gaps.
- Fast-growing bumps. Some melanomas are raised, firm, and one even color. A spot that is growing quickly or feels different deserves attention even if it passes the ABCDE check.
- Skin-colored or pink spots. Not every melanoma is dark. Some are pink, red, or skin-colored, which makes them easy to overlook.
- Palms, soles, and nails. Melanoma can appear on the palms, the soles of the feet, between the toes, and as a new dark streak under a nail. These spots are easy to miss, so check them on purpose.
This matters for everyone, and it matters for people with brown and black skin. Melanoma is less common in darker skin, but it is often found at a later stage.15 Outcome gaps for melanoma on the hands and feet are real and are not explained by late diagnosis alone.16 The takeaway is the same for all skin tones: check everywhere, including soles and nails, and get a new, changing, bleeding, or non-healing spot looked at, even if a rule or an app says it looks fine.
When to see a doctor
A self-exam is a way to decide when to call, not a way to clear a spot yourself. Have a clinician check any spot that is new, growing, changing color, bleeding, itching, or not healing. Show them the spot that looks different from your others. If you have fair skin, a lot of past sun, many moles, or a personal or family history of skin cancer, ask about a regular professional skin exam. Catching a skin cancer early is still the most dependable way to keep treatment small and simple.1
Worried about a spot?
SpotDoc offers full-body skin cancer screening in Brownwood Square, The Villages. No referral needed for most plans.
Frequently asked questions
How often should I check my skin? Many dermatology groups, including the American Academy of Dermatology, suggest a self-check about once a month, which is a reasonable rhythm for most people. No study has proven that a particular schedule lowers the risk of dying from skin cancer, so the real goal is to check often enough to know what is normal for you and to notice change. Pick a routine you will keep, and look more often if you are at higher risk or watching a particular spot.
Does checking my own skin lower my risk of dying from melanoma? There is no randomized trial proving that. What is clear is that skin cancer found earlier, while it is thinner, is tied to better outcomes. A self-exam is useful awareness that works best alongside professional skin exams, not a replacement for them.
What is the ugly duckling sign? Most of your moles look alike. The ugly duckling is the spot that stands out as different from the rest. That odd one is the one to show a doctor, even if it does not clearly break the ABCDE rule.
Can a mole-check app tell me if a spot is cancer? No. When these apps were tested, the results were poor and uneven, and some missed melanomas entirely. An app may help you remember to look, but it cannot confirm a spot is safe. See a clinician for anything that worries you.
Where do people most often miss a melanoma? On hard-to-see areas, especially the back, and on places people forget to check, like the scalp, soles, between the toes, and under the nails. A mirror and a partner help cover these spots.
Questions to ask your dermatologist
- Given my skin type and history, how should I check my own skin?
- How often should I have a professional skin exam?
- Which of my spots should I watch, and what change should make me call?
- Should I take baseline photos of any spots to track them?
- What kinds of melanoma might a simple self-check miss for me?
Reviewed by Tyler Long, DO. Last reviewed June 2026.
Update log
How this guide has changed since it was first published.
- September 1, 2026Guide published.
References
Every statement on this page is backed by the peer-reviewed sources below — each links to the original study. Numbers match the citations in the text and the grids above.
- Henrikson NB, Ivlev I, Blasi PR, et al. Skin cancer screening: updated evidence report and systematic review for the US Preventive Services Task Force. JAMA. 2023;329(15):1296–1307.View source
- Abbasi NR, Shaw HM, Rigel DS, et al. Early diagnosis of cutaneous melanoma: revisiting the ABCD criteria. JAMA. 2004;292(22):2771–2776.View source
- Scope A, Dusza SW, Halpern AC, et al. The "ugly duckling" sign: agreement between observers. Arch Dermatol. 2008;144(1):58–64.View source
- De Giorgi V, Grazzini M, Savarese I, et al. The impact of body area in melanoma self-detection: a retrospective study. Eur J Cancer Prev. 2015;24(4):343–346.View source
- Kittler H, Seltenheim M, Dawid M, Pehamberger H, Wolff K, Binder M. Morphologic changes of pigmented skin lesions: a useful extension of the ABCD rule for dermatoscopy. J Am Acad Dermatol. 1999;40(4):558–562.View source
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- Berwick M, Begg CB, Fine JA, Roush GC, Barnhill RL. Screening for cutaneous melanoma by skin self-examination. J Natl Cancer Inst. 1996;88(1):17–23.View source
- Paddock LE, Lu SE, Bandera EV, et al. Skin self-examination and long-term melanoma survival. Melanoma Res. 2016;26(4):401–408.View source
- Johansson M, Brodersen J, Gøtzsche PC, Jørgensen KJ. Screening for reducing morbidity and mortality in malignant melanoma. Cochrane Database Syst Rev. 2019;6(6):CD012352.View source
- De Giorgi V, Grazzini M, Rossari S, et al. Is skin self-examination for cutaneous melanoma detection still adequate? A retrospective study. Dermatology. 2012;225(1):31–36.View source
- Freeman K, Dinnes J, Chuchu N, et al. Algorithm based smartphone apps to assess risk of skin cancer in adults: systematic review of diagnostic accuracy studies. BMJ. 2020;368:m127.View source
- Chuchu N, Takwoingi Y, Dinnes J, et al. Smartphone applications for triaging adults with skin lesions that are suspicious for melanoma. Cochrane Database Syst Rev. 2018;12(12):CD013192.View source
- Kassianos AP, Emery JD, Murchie P, Walter FM. Smartphone applications for melanoma detection by community, patient and generalist clinician users: a review. Br J Dermatol. 2015;172(6):1507–1518.View source
- Yagerman S, Marghoob A. Melanoma patient self-detection: a review of efficacy of the skin self-examination and patient-directed educational efforts. Expert Rev Anticancer Ther. 2013;13(12):1423–1431.View source
- Mangione CM, Barry MJ, Nicholson WK, et al. Screening for skin cancer: US Preventive Services Task Force recommendation statement. JAMA. 2023;329(15):1290–1295.View source
- Grant S, Revan D, Tang L, et al. Disparities in acral lentiginous melanoma: factors beyond delayed diagnosis. J Am Acad Dermatol. 2025;93(4):1018–1026.View source
- Weinstock MA, Risica PM, Martin RA, et al. Melanoma early detection with thorough skin self-examination: the "Check It Out" randomized trial. Am J Prev Med. 2007;32(6):517–524.View source
- Hamidi R, Peng D, Cockburn M. Efficacy of skin self-examination for the early detection of melanoma. Int J Dermatol. 2010;49(2):126–134.View source
- Turrisi R, Hultgren B, Mallett KA, Martini M, Robinson JK. Comparison of efficacy of differing partner-assisted skin examination interventions for melanoma patients: a randomized clinical trial. JAMA Dermatol. 2015;151(9):945–951.View source
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