The Yorkshire Terrier is one of the smallest dog breed of terrier type, and of any dog breed. The breed developed during the 19th century in Yorkshire, England. The breed developed during the 19th century in Yorkshire, England. Ideally its maximum size is 7 pounds (3.2 kg). It has a grey, black and tan coat, and the breed's nickname is Yorkie. Health issues often seen in the Yorkshire Terrier include bronchitis, lymphangiectasia, portosystemic shunt, cataracts, and keratitis sicca. Additionally, Yorkies often have a delicate digestive system, with vomiting or diarrhoea resulting from consumption of foods outside of a regular diet. The relatively small size of the Yorkshire Terrier means that it usually has a poor tolerance for anaesthesia. Injection reactions (inflammation or hair loss at the site of an injection) can occur. In addition, allergies can cause skin to be dry, itchy and/or red. Legg–Calvé–Perthes syndrome, which causes the top of the femur (thigh bone) to degenerate, occurs in Yorkies in certain lines.