One of the most common things I hear in consultations is some version of “I didn’t know what to call it.” Someone recently described a seborrheic keratosis to me as looking like “a crusty mole,” which is a completely reasonable way to describe it if you don’t know the medical term. Most people don’t walk around knowing the names of skin conditions, and there’s no reason you should; that’s exactly what I’m here for. But if you’re trying to work out what’s on your skin before booking a consultation, it helps to know roughly what you’re looking at, so here’s a plain-language guide based on appearance rather than medical terminology.