Factors associated with an increased risk:
(1) injecting a "speedball" (mixture of cocaine and heroin)
(2) subcutaneous and/or intramuscular injecting ("skin popping")
(3) for males, increasing numbers of female sex partners over lifetime
(4) use of dirty needles
(5) "booting" prior to injection (drew blood into syringe before injection, typically during intravenous injection)
(6) Asian race
(7) female gender
Factors associated with decreased risk:
(1) clean the skin with alcohol prior to injection
(2) age >= 50 years
Interventions that may reduce risk of skin and soft tissue abscesses:
(1) clean needle program
(2) cleaning skin prior to injection
(3) enrollment in a methadone maintenance program
