Seborrhoeic keratosis is a harmless warty spot that appears during adult life as a common sign of skin ageing. Some people have hundreds of them on their back, scalp and torso.
Seborrhoeic keratosis or SK for short is a basal cell papilloma, senile wart, brown wart, wisdom wart, or barnacle. The descriptive term, benign keratosis, is a broader term that is used to include the following related scaly skin lesions:
Seborrhoeic keratosis
Solar Lentigo (which can be difficult to distinguish from a flat seborrhoeic keratosis)
Lichen planus-like keratosis (which arises from a seborrhoeic keratosis or a solar lentigo).