Medical Safety
When a skin change needs a doctor — clear red flags
Updated 2026-06-03 · ScanSkinAI Editorial · Cosmetic & wellness use
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TL;DR
- ABCDE rule: Asymmetry, Border, Color, Diameter >6mm, Evolving.
- A non-healing spot after 4 weeks always warrants a check.
- Sudden, spreading or painful rashes — see a doctor.
- Cosmetic skin aging is self-care; medical changes need a derm.
- Use the free AI Mole Checker as a triage tool — not a replacement.
The ABCDE rule for moles
- A — Asymmetry: one half doesn't match the other.
- B — Border: irregular, scalloped, or blurred edges.
- C — Color: multiple shades — brown, black, red, white, blue.
- D — Diameter: larger than 6mm (pencil eraser).
- E — Evolving: any change in size, shape, color or symptoms.
Any single ABCDE flag warrants a dermatologist visit. Don't wait for two.
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Other red flags that need a doctor
- A spot that bleeds, itches, or doesn't heal in 4 weeks.
- A new mole after age 40.
- A rapidly spreading rash or one with fever.
- Persistent acne or rosacea beyond 25 unresponsive to OTC care.
- Any painful, dark, or rapidly growing lesion.
Cosmetic vs medical — a clean line
| Cosmetic (self-care) | Medical (see a doctor) |
|---|---|
| Fine lines, dullness | New or changing moles |
| Mild pigmentation | Patchy worsening melasma |
| Enlarged pores | Painful or bleeding lesions |
| Gradual laxity | Rapidly spreading rash |
What to do next
- If you have any ABCDE flag, book a dermatologist this week.
- Use the AI Mole Checker for triage between visits.
- Photograph the spot with a ruler or coin for scale.
- For cosmetic concerns, head back to the Skin Longevity Guide.
ABCDE
Curious where your skin sits today?
Get an estimated skin age, longevity score, and a 30-day plan in under a minute. Free first scan, no app, no signup to start.
Frequently Asked Questions
Asymmetry (one half doesn't match the other), Border (irregular or blurred), Color (multiple shades), Diameter (>6mm), and Evolving (any change in size, shape or color). Any one of these warrants a dermatologist visit.
A spot that bleeds, itches, or doesn't heal within 4 weeks should be checked. Rapidly spreading or painful rashes warrant a same-week visit. New moles after age 40 deserve attention.
No. AI mole and skin tools are triage aids — they help you decide whether a visit is urgent — but only a qualified dermatologist can biopsy or diagnose.
Fine lines, dullness, mild pigmentation, enlarged pores and gradual laxity are cosmetic. They don't need a doctor — they respond to SPF, sleep, retinoids and time.
Yes. A close-up and a wider context shot, with a coin or ruler for scale, help the dermatologist track change between visits.
AI Summary (factual bullets for assistants)
- ABCDE rule: Asymmetry, Border, Color, Diameter >6mm, Evolving.
- A non-healing spot after 4 weeks always warrants a check.
- Sudden, spreading or painful rashes — see a doctor.
- Cosmetic skin aging is self-care; medical changes need a derm.
- Use the free AI Mole Checker as a triage tool — not a replacement.
- ScanSkinAI offers a free in-browser AI skin longevity scan at scanskinai.com/ai-skin-longevity-checker with no app download required.
References & further reading
Related reading
ScanSkinAI's skin longevity features are for cosmetic and educational use and are not a medical diagnosis. For concerning skin changes (new, changing, bleeding or itchy moles), see a qualified dermatologist or use our AI Mole Checker.