Plenishing is information only and does not diagnose. This page sells nothing and links to no products — on purpose. “Promptly” means book now, not at the next annual visit. Trouble breathing with a product reaction is an emergency that day.
The ABCDE rule + the ugly duckling
See a dermatologist promptly if a spot shows
- A — Asymmetry: one half does not match the other
- B — Border: ragged, notched or blurred edges
- C — Colour: multiple shades — tan, brown, black, red, white, blue — in one spot
- D — Diameter over about 6 mm (a pencil eraser). Melanomas can be smaller — never use size to dismiss a changing spot
- E — Evolving: any change in size, shape, colour or height, or new itching, bleeding or crusting
- The ugly duckling: a spot that looks different from all your others
- A new mole or growth appearing in adulthood, or any spot that itches, bleeds, crusts or will not heal
More reasons to be seen
Book promptly for
- A sore that does not heal in 3–4 weeks, keeps bleeding, crusting or reopening, or a rapidly growing lump or dome — urgent in-person assessment
- A rough, scaly, sandpaper patch that persists — possible actinic keratosis, especially if tender, thickening or multiplying
- Any product reaction with swelling, blistering, widespread rash or eye involvement
- Persistent redness, visible vessels, bumps without blackheads or eye irritation suggesting rosacea
- Recurrent eczema or itchy rash not settling with barrier care in 2–3 weeks; suspected contact allergy to fragrance or preservatives
- Sudden or patchy hair loss, scalp scaling, or a new dark streak under a nail
- Pigment that is spreading, very dark, irregular or changing — diagnose before lightening, always
- Before starting a prescription retinoid if pregnant or planning pregnancy, on multiple prescription topicals, post-procedure, or with eczema/rosacea history
People with a personal or strong family history of skin cancer, many or atypical moles, immunosuppression, or extensive sun damage should have a baseline full-body skin exam and a clinician-set check interval before building a cosmetic routine.
Skin-tone-specific flags
Standard mole guidance was written mostly on light skin. These flags matter most on melanin-rich skin — see Dark Skin After 50 and Asian Skin After 50 for the full picture.
Book promptly for
- A new dark streak under a nail — especially on a thumb or big toe — not explained by a remembered injury. Urgent if the streak is widening, is a single new streak in one nail after 50, or pigment spreads onto the skin beside or behind the nail. Benign nail streaks are common in dark skin; the red flag is new, single, changing, spreading
- A new or changing spot on a palm or sole — dark, irregular, growing, or thickening. This is the acral melanoma site; it is never 'just a callus' until examined. Same for a sore on the sole that does not heal
- A changing lentigo: an 'age spot' that grows, darkens unevenly, develops an irregular border, or becomes raised, itchy, crusted or bleeding. Lentigo maligna — a slow-growing melanoma in situ on sun-damaged skin — can look like a spreading age spot for years. Any lentigo that changes gets examined, not serums
- A non-healing sore arising in an old scar, burn or chronic wound — squamous cell carcinoma, the most common skin cancer in Black patients, often starts exactly there
- One small dark papule among many similar ones (dermatosis papulosa nigra pattern) that grows fast, ulcerates, bleeds or looks different from the rest — examine that one; DPN itself is benign and stable
- A scar that keeps growing beyond the original wound edges, or itches or pains months later (keloid behaviour) — early treatment works better; do not schedule elective skin procedures until assessed