You've got a lot of skin, about 20 square feet of it. With so much skin hanging out there in the heat and cold, wind and sun, it's not surprising that you might have the occasional bump or blemish. What about that scaly patch of skin on your knee (might be psoriasis) or that rough red patch of skin on your nose (could be skin cancer)? Is it serious? Is there a cure or some type of treatment? The answer to the latter is usually yes.

Take a tour through our guide to the most common skin conditions, and you'll find not only pictures of those annoying lumps and bumps, but also information aplenty on causes, treatments and ways to prevent them from coming back.

Speaking of prevention, did you know that two of the most serious skin maladies, cancer and premature aging of the facial skin, are often preventable? You have to start early, though. Click here to find information about kids and their skin.