Seborrheic keratosis: symptoms, treatment, and when to worry
Last updated September 3, 2026.
Seborrheic keratoses are harmless skin growths that look like waxy, raised, brown or black blobs stuck onto the skin, appearing from middle age onward. They are not contagious, not caused by a virus, and never turn into skin cancer. Most people collect several as the years pass, and they need no treatment unless they itch, catch on clothing, or bother you cosmetically.
What do they look like?
The classic description: a waxy, rough, slightly raised patch that looks pasted or stuck onto the skin surface, ranging from pale tan to dark brown or black, from a few millimeters to a few centimeters. Common sites are the chest, back, face, and scalp. They can arrive singly or in crops, and the number tends to grow with age. The dark ones worry people, which is understandable, because color overlap with melanoma is the whole reason some get checked.
What actually helps?
- Usually, nothing: a confirmed seborrheic keratosis needs no treatment and no follow-up.
- One professional look for new dark lesions: any new pigmented growth deserves a clinician's examination, because melanoma is the diagnosis that must not be missed, and dermoscopy settles most cases in seconds.
- Removal when they trouble you: catching on clothing or jewelry, bleeding from friction, itching, or cosmetic distress are all valid reasons. Freezing, scraping, or cautery remove them quickly in clinic.
- Leave the home remedies alone: picking, cutting, or acid treatments scar and can infect, and they never beat a quick clinic removal.
- Expect company: new ones appear over the years, which is normal, not a sign of spread or treatment failure.
When is it an emergency?
Seborrheic keratoses are never an emergency. The prompt-review signs are the melanoma rules applied to any pigmented skin lesion: rapid growth or change, an irregular or notched border, multiple colors within one lesion, bleeding without injury, or a lesion that looks distinctly different from your others. Also review any lesion that repeatedly inflames or fails to heal. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
What a Pymander AI doctor consult looks like
Illustrative example, not a real member's messages.
Common questions
How do doctors tell a seborrheic keratosis from melanoma?
By examination, usually with a dermatoscope: seborrheic keratoses show a characteristic stuck-on, waxy surface with tiny plugged pits and ridges that melanomas lack. The reassurance features are the waxy pasted look, a stable appearance, and company, several similar lesions. The red flags pushing the other way are rapid change, irregular borders, multiple colors, and bleeding without injury. When the eye cannot settle it, a small biopsy can.
Can seborrheic keratoses turn into cancer?
No. They are benign growths of the skin's outer layer and do not transform. The cancer question arises only because dark keratoses can resemble melanoma to the untrained eye, so new or changing pigmented lesions are checked once for the label, then left alone. The exception that proves the rule: a sudden eruption of very many keratoses at once is worth mentioning to a doctor, as it can rarely accompany internal illness.
Why am I suddenly getting these growths?
Age and genetics, mostly. Seborrheic keratoses begin appearing from middle age onward and accumulate, some families collect dozens. They are not caused by sun in the direct way skin cancers are, not contagious, not from any virus, and not a sign of anything wrong inside. 'Suddenly' usually means you have started noticing a process that has been quietly running for years.
What does removal involve and will it scar?
Quick clinic procedures: freezing with liquid nitrogen, scraping off under local anaesthetic, or cautery. Healing leaves a flat area that initially looks lighter or pinker than the surrounding skin and usually blends over months. Home removal attempts, picking, cutting, acids, scar worse and risk infection, and they are the commonest way a benign lesion turns into a lasting mark. If a lesion bothers you, the clinic version is quick and clean.
Do seborrheic keratoses need follow-up?
Confirmed ones, no. They can be safely ignored for life. The exceptions: a lesion that changes rapidly, bleeds without friction, or looks unlike your others earns a fresh look. Some people photograph theirs to make 'stable versus changing' objective. New lesions arriving with age is the expected pattern and does not itself need review unless one breaks the melanoma rules.
Can I prevent seborrheic keratoses?
Not really. They are an age-and-genetics phenomenon with no proven prevention. General skin sense, sun protection, still applies for the genuinely preventable problems, skin cancers and photoaging, so the sunscreen habit is worth keeping, but it will not stop keratoses arriving. The practical prevention is early labeling: get the first ones confirmed, so every later lookalike is measured against a known baseline.