What causes Skin Picking Disorder?

“The cause of this disorder remains a mystery. However, research shows that some animals also pick or chew at their bodies, causing great damage. Because of this similarity, and the fact that in some women skin picking can fluctuate with the menstrual cycle, many believe that skin picking has an underlying genetic or biological cause.” – TLC

More research needs to be done to find out if there is an underlying genetic or biological cause because if there is it could pave the way for an effective treatment plan and/or cure. My family dog chews and licks at his skin to the point he is covered in lesions and loses hair because of it… the vets say that he has allergies but he has tried EVERY medication, steroid cream, and oral treatment there is and he STILL does it! Like my skin picking, which developed after I moved states from NSW to QLD, his skin chewing/licking developed after we moved states from QLD to WA. Just a coincidence?