What Causes Itchy Lesions On Wrist?

I have 3 small marks on my wrist that really hurt. The larger one has some pus in it, very small though. They also itch very much. I woke up in the middle of the night itching them like crazy. It's been about 3 days now and they really hurt today. I have no idea what they could be? I am a neat freak and would know if we had any kind of bugs in the house. They only ones I've seen are very small ants by our sliding glass doors. What could this be?