Sudden change in behavior

Question
Hi
I have had my dog, Bella, since she was a puppy, she is now two years old, is a pit bull and up until now has been a very health and happy dog; she has been showing signs of being skittish, while sleeping, if there are any sudden movements, she jumps up and at the person who made the noise, she has also, nipped at the face of a three year old boy who was in her face also, but he was not touching her, just talking to her.  Bella has always been very sweet and loving and these behaviors have been almost sudden within the last month, I hope you have some advice for me, I don't want to lose her, she is part of my life, but I do not want anyone getting bitten either.  Thank you for your time
Lorraine and Bella

Answer
This isn't an issue that can easily be solved, much less through email, but I will try to offer some thoughts.

Based solely on what you have written, it sounds as if the dog has been teased or disturbed while sleeping and is now fearful the same thing will happen again when she falls asleep.  Is it possible some could have scared her or hurt her while she was sleeping?

My recommendation would be, for her safety and that of visitors to your home, to keep her in another room, or in a dog crate, when you cannot monitor the behavior of those interacting with her.

And as an additional word about dog crates, dogs like their crates when they are introduced to them properly and used properly.  It gives the dog a safe haven away from commotion.

http://www.ddfl.org/behavior/crate-train.pdf
http://www.hsmo.org/m_obedience/behavior/dogcrate.html