The "Age Spot" You've Ignored for Ten Years May Never Have Been One
There's a dark spot on your arm, back or foot. It hasn't changed much in years, so you've always called it an "age spot" and moved on.
Most of the time, you're right. Age spots and "stuck-on" seborrheic keratoses are very common and harmless. But "most" isn't "all." A small number of dark spots look much like age spots and turn out to be melanoma, the most dangerous skin cancer.
The good news is that a few simple observations can tell you which spots can be left alone and which deserve a doctor's eye. This guide covers three look-alikes, the ABCDE rule, and the places on the body that matter most in Asian skin: palms, soles and nails.
🔍 Three Look-Alikes
"Age spot" is a catch-all. Behind it can be three very different things.
1. Solar lentigo (the classic age spot)
A flat, evenly colored, sharply bordered brown spot caused by accumulated UV exposure. Common on the face, backs of the hands and forearms. Benign. See Blog 1 in this series.
2. Seborrheic keratosis (SK)
A benign overgrowth of skin cells and one of the most common benign skin growths in adults.
Look: slightly raised, waxy or rough, like a lump of clay or dough pressed onto the skin.
Color: light tan to dark brown, sometimes nearly black. Spots on the same person can vary a lot.
Where: back, chest, face, neck, scalp. Not limited to sun-exposed areas.
Number: tends to increase with age. A few to dozens.
Cause: linked more to genetics and age. The role of sun is unclear. It isn't contagious and isn't related to hygiene.
Symptoms: usually none, but it can itch, or get irritated, inflamed or bleed from rubbing.
Nature: benign. It doesn't turn into cancer.
3. Melanoma
A malignant tumor arising from pigment cells. It is a small share of skin cancers but causes the most skin cancer deaths. It can appear on sun-exposed skin and on skin that rarely sees the sun.
Look: often asymmetric, with irregular borders and uneven color. It can also look almost identical to an ordinary mole or age spot.
Hallmark: it changes. This is the single most important feature.
Nature: malignant. Caught early and removed, outcomes can be very good.
⏱️ Why This Matters
Early detection changes outcomes. Melanoma confined to the top layers of skin has a high long-term survival rate after surgery. Once it spreads, outlook worsens significantly.
"Ordinary-looking" is the trap. Early melanoma is usually painless and itch-free, so it is easily mistaken for an age spot, a mole or a bruise.
The pattern in Asian populations differs. In lighter-skinned populations, melanoma is mostly sun-related and common on the trunk and legs. Among Asians, acral lentiginous melanoma (on palms, soles and nails) makes up a substantial share. These areas see little sun, so many people assume "I'm safe."
Delays are common. A dark patch on the foot or nail is often written off as a bruise, callus or old injury for months.
Melanoma is generally less common in Hong Kong than in Western countries. Less common isn't the same as never, and it isn't a reason to ignore changes.
The aim here is not to alarm you. It is to show you where to look and what to look for.
🔤 The ABCDE Rule
ABCDE is a simple checklist dermatologists use to decide whether a mole or spot needs examination.
Three tips for using it
One sign is enough to take notice. You don't need all five.
"Evolving" matters most. A spot unchanged for ten years and one that grew in three months carry very different risks.
ABCDE isn't perfect. Some melanomas, such as nodular melanoma, break the rules. They may be red or skin-colored, raised, firm and fast-growing. The EFG add-on helps: Elevated, Firm, Growing.
The "ugly duckling" rule
Most of your moles and spots share a family resemblance. A spot that looks clearly different, darker, larger, paler or oddly shaped, is the ugly duckling and deserves a doctor's look.
🦶 Three Places That Matter Most in Asian Skin
This is the most important section. These areas rarely see the sun, yet they are common melanoma sites in Asian populations, and the easiest to overlook.
A well-known example
Musician Bob Marley's melanoma first appeared under a toenail and was initially attributed to a soccer injury. The case is often cited as a reminder that dark changes on nails or soles shouldn't automatically be blamed on trauma.
🎭 Other Skin Problems That Pose as Spots
Lentigo maligna: a flat, slowly spreading, unevenly colored patch on chronically sun-damaged face or neck. It is a form of melanoma in situ and is easily mistaken for an age spot.
Pigmented basal cell carcinoma: a pearly small bump, sometimes brown or black, with rolled edges that may bleed or crust.
Actinic keratosis: rough, scaly, sandpaper-like red or brown patches. Pre-cancerous, common on sun-damaged face, scalp and hands.
Amelanotic melanoma: not always dark. It can be pink, red or skin-colored.
🪞 How to Check at Home (About 10 Minutes)
Good light. Natural or bright light, with a full-length mirror and a hand mirror.
Head to toe. Scalp (part the hair), face, behind ears, neck, chest, back, buttocks, arms, palms, nails, thighs, calves, soles, between toes, toenails.
Ask someone to check your back and scalp.
Photograph. Place a ruler or coin beside any questionable spot for scale.
Repeat every 1–3 months, especially if you have many moles, a family history of melanoma or a history of bad sunburn.
Who should be extra watchful
People with many moles (for example more than 50) or atypical moles
A family history of melanoma
Previous severe sunburn or skin cancer
Long-term immune suppression (for example after an organ transplant)
🩺 What Happens at the Doctor's Office?
Fear of the unknown keeps many people away. The process is simple:
History: when the spot appeared, whether it changed, family history.
Visual exam: the doctor checks your whole skin, not just the spot you point to.
Dermoscopy: a handheld magnifier with light shows the spot's inner structure. It's painless, non-invasive and takes seconds.
Biopsy if needed: after local anesthetic, part or all of the spot is removed and sent for lab examination. It is the most reliable diagnostic method.
Results and follow-up: a benign result usually means advice on whether removal is needed. A suspicious one leads to further treatment.
Why not treat it yourself first?
Burning, scraping, freezing or grinding a suspicious spot can destroy the tissue needed for diagnosis and delay it. The safe order is diagnose first, treat later.
💭 4 Common Myths
"No pain, no itch, no problem." Early melanoma usually has no symptoms.
"I don't tan, so I'm safe." Acral melanoma occurs on skin that rarely sees the sun.
"Only black spots are dangerous." Some melanomas are pink, red or skin-colored.
"Touching or scratching a spot makes it cancerous." There is no evidence that light contact turns a benign spot cancerous. But repeated scratching alters its look and makes assessment harder.
❓ Frequently Asked Questions
Disclaimer: This article is for general education only. It can't diagnose and doesn't replace professional medical advice. Any changing, suspicious or worrying skin lesion should be examined by a registered doctor, such as a dermatologist.
Source directions: Hong Kong Cancer Registry; Hong Kong College of Dermatologists public education; Hong Kong Anti-Cancer Society; American Academy of Dermatology; NHS and Cancer Research UK melanoma information; published ABCDEF criteria for nail pigmentation.
