The Health Department is warning doctors to prepare skin properly before giving injections following the death of a man from a 'flesh-eating disease' after receiving an injection. The 55-year-old Wan Chai man died days after contracting necrotising fasciitis, the third death in 12 infections this year, the Centre for Health Protection confirmed yesterday. The case has been handed to the Coroner's Court, and the Department of Health is investigating. The man had gone to a private doctor over neck pain and upper respiratory tract symptoms on Sunday and received an injection to reduce inflammation. He developed pain in his right buttock, along with chills and rigor, on Monday and was admitted to St Teresa's Hospital on Tuesday for surgery to remove part of the buttock. He was transferred to Pamela Youde Nethersole Eastern Hospital, where he died on Thursday. Laboratory tests found Streptococcus pyogenes, one of the types of bacteria that can cause necrotising fasciitis, in samples from the buttock. Microbiology expert Ho Pak-leung said one in 10 sore throat cases were caused by the bacteria, which can be passed by casual contact. 'But in most cases it will not cause the flesh-eating disease if it does not go into the blood,' he said. While not confirming the injection was the cause of the fatal infection, Director of Health Lam Ping-yan said the department would remind doctors to perform proper skin preparation before injections.