A seborrhoeic keratosis is a benign overgrowth of the skin's outermost cells — a waxy, warty plaque that looks pasted onto the surface, as if it could be picked off with a fingernail. It is not a wart, not contagious, not cancer, and not caused by anything you did. It is, overwhelmingly, just accumulated birthdays.
WhatsApp Dr Sin Yong →Seborrhoeic keratoses are among the most common benign skin tumours in humans — reviews describe them as near-universal with ageing, driven by clonal changes in keratinocytes rather than by sun alone, though sun-exposed sites carry more [1]. They begin as flat tan patches and thicken over years into the classic waxy plaque. They run in families. They are not viral warts, despite the nickname — nothing spreads them, and picking one off (a popular home experiment) just brings it back from the base with a scab for company.
A seborrhoeic keratosis itself never becomes cancer. The clinical issue is the mimic: a melanoma can masquerade as a dark, irregular “SK”, and studies of excised lesions show a small but real rate of misdiagnosed malignancy hiding in presumed keratoses [1,2]. The rule Dr Sin Yong applies is absolute: any pigmented growth gets examined — dermatoscope where indicated — before anyone freezes, burns or lasers it. Destroying a lesion without diagnosis destroys the evidence. Features that fast-track review: rapid change, bleeding, an outlier that looks different from your other spots, or new pigmented lesions appearing in numbers.
Once confirmed benign, removal is elective and straightforward: cryotherapy for thin lesions, curettage or electrocautery for thicker ones, and ablative laser where precision or cosmetically sensitive sites call for it — the comparative literature supports all of these, chosen by lesion thickness and site [1,2]. On the face, technique matters more than modality: depth control determines whether the result is clear skin or a pale mark. Darker skin types need particular care with cryotherapy, which can leave lasting pigment change — one reason laser-based removal is often preferred in Singapore skin. Related surface concerns — flat brown patches and texture — are different problems with different tools.
Creams — no topical dissolves a thick keratinocyte plaque reliably; the “SK removal” products sold online mostly irritate. Picking — it regrows from the base. Home freezing kits — uncontrolled depth on an undiagnosed pigmented lesion is the worst combination in dermatology. And ignoring the changing one because “it's just an age wart” — the mimic problem is exactly why the changing one earns a doctor's eyes.
“A seborrhoeic keratosis never turns into cancer — but cancer occasionally dresses as one, which is why diagnosis comes before destruction.”
— Dr Sin Yong
No. Despite the 'wart' nickname they are not viral — nothing spreads them between people or across your own skin.
Numbers rise with age and family tendency. A genuinely sudden eruption of many new lesions is uncommon and worth a medical review rather than assumption.
Not reliably — some melanomas imitate the waxy look convincingly. The stuck-on appearance is reassuring but not diagnostic; examination takes minutes and settles it.
Removal is done under local anaesthetic or with brief, tolerable discomfort depending on modality and size. Most patients find it far easier than expected.
A properly removed lesion rarely regrows, but new ones can appear elsewhere over the years — the tendency is constitutional.
No proven prevention exists; they are largely genetic and age-driven. Sun protection is sensible for many reasons but only partially influences these.