When you're evaluating a patient with GPP, you have to think about other entities besides GPP. We have to think about infections, that's a common cause of pustulosis. We have to think of pustular drug eruption such as ajab. Those are also very common. Occasionally when you have this common sort of confined GPP, that is, pustules on plaques, we have to think of even folliculitis. So those are common things that should be running through your head when you see a patient who has suspected GPP. Oftentimes a biopsy is the best way to exclude these other entities. As well as a careful history. History can often direct you to the diagnosis of GPP.