Seborrheic Keratoses
Seborrheic keratoses are common benign, "stuck-on" skin growths, described in the AAFP review of benign skin tumors.
Symptoms
Waxy, "stuck-on" looking brown, black, or tan growths with a rough or warty surface, most common on the trunk, face, and scalp in older adults.
Causes and risk
The exact cause isn't fully understood; they become more common with age and can run in families, but sun exposure is not a clear driver the way it is for other skin lesions.
How it is evaluated
Diagnosis is usually clinical from the classic waxy, stuck-on appearance; dermoscopy helps identify features like the blue-black sign that can flag the rare melanoma mimicking a seborrheic keratosis, per dermoscopy research. Any uncertain lesion should be biopsied.
Treatment
Removal (cryotherapy, curettage, shave, or laser) is elective for comfort or cosmetic reasons; cryotherapy can cause pigment changes, particularly in darker skin tones.
When to seek care
A lesion that changes rapidly, bleeds, itches persistently, or looks different from a patient's other seborrheic keratoses warrants evaluation to exclude melanoma. A sudden eruption of many new lesions at once (sign of Leser-Trélat) is a recognized, though rare, marker worth flagging to a clinician.