GMC-Registered · UK skin cancer specialist
Dermatologist's quick take
- Most moles are completely harmless — but change is the universal warning sign
- A mole that bleeds, itches, or doesn't heal needs assessment within 4 weeks
- New moles after age 40 should be checked, even if they look benign
- Pigmented streaks on nails or moles under nails warrant urgent dermatology review
- Annual professional checks + monthly self-checks halve melanoma mortality
I'm Dr. Iwasa, and "should I worry about this mole?" is the single most common question I'm asked in clinic — by patients, friends, and even strangers at parties. The honest answer is: usually no, but sometimes yes, and the difference matters more than almost any other dermatology decision.
This guide gives you a clear set of red flags. If any apply to you, book a dermatologist this week. Between visits, use ScanSkinAI's AI mole check to track changes objectively.
The 9 warning signs
1. Recent change
Any change in size, shape, colour, or elevation in the past 3 months.
2. New mole after 40
Most benign moles appear before adulthood. New pigmented lesions in midlife deserve evaluation.
3. Bleeding or crusting
Spontaneous bleeding, oozing, or crusting that doesn't heal within 2 weeks.
4. Itch or pain
Persistent itching, tenderness, or burning in a single mole.
5. Non-healing bump
A pink or red bump that has been there for 4+ weeks and isn't healing.
6. Nail pigmentation
A dark streak under a fingernail or toenail, or pigment extending into the cuticle (Hutchinson's sign).
7. The ugly duckling
A mole that looks distinctly unlike your other moles — darker, lighter, larger, or differently shaped — is statistically more likely to be melanoma than a mole that fits your normal pattern.
8. Multiple colours within one mole
Brown, black, red, white, or blue patches within a single lesion. Healthy moles are usually one uniform shade. This corresponds to the "C" of the ABCDE rule.
9. Family or personal history
A first-degree relative with melanoma roughly doubles your risk. A personal history of melanoma means new moles need closer attention. People with 50+ moles or atypical naevi syndrome should see a dermatologist annually.
What dermatologists actually do
In clinic, I use a dermatoscope — a polarised magnifier that reveals patterns invisible to the naked eye. Most "scary-looking" moles turn out to be perfectly benign under dermoscopy. Conversely, some innocent-looking lesions reveal melanoma-specific features. This is why a 5-minute dermatologist visit beats months of internet anxiety.
What to bring to your dermatology appointment
- Photographs of the mole over time, with dates
- Family history of melanoma (parents, siblings)
- List of all medications, especially immunosuppressants
- Sun exposure history — childhood sunburns, tanning beds, outdoor work
- Any prior biopsies or skin cancers, including basal/squamous cell
Same-week dermatology referral if you have:
- A mole that has visibly changed in the past 4–8 weeks
- A non-healing skin lesion that bleeds repeatedly
- A new pigmented streak under a fingernail or toenail
- A pink/red bump growing over weeks (rule out nodular or amelanotic melanoma)
In the UK, ask your GP about the 2-week-wait suspected melanoma pathway.
How to monitor between visits
Photograph any concerning mole monthly, against the same background and lighting. A free AI mole check at ScanSkinAI applies ABCDE analysis automatically and stores dated photos for you. This evidence is what lets dermatologists make confident decisions — change over time is the strongest melanoma indicator.
For the underlying framework dermatologists use, see our guide to the ABCDE rule and how often you should get a skin check.
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Frequently Asked Questions
Dr. Celina Kazumi Iwasa
VerifiedGMC-Registered · UK Hospital + Private Practice · Skin Cancer Screening Specialist
Dr. Iwasa is a GMC-registered dermatologist working across UK hospital and private practice settings. She specialises in skin cancer screening, mole assessment and dermoscopy, with a focus on UK and European patients across Fitzpatrick I–IV skin types.