Drug injections scars:
(1) Intravenous injections ("mainlining") can result in linear scars ("tracks") overlying veins which may be hyperpigmented.
(2) Subcutaneous injection ("skin popping") can result in punched out, atrophic scars.
According to Horowitz, the severity of scarring depends on:
(1) the number of years of drug use
(2) recent drug use (although scarring may persist for years after stopping the practice)
Common sites:
(1) back of the hands
(2) forearms
(3) wrists
(4) antecubital fossa
Less obvious sites:
(1) popliteal fossa
(2) inner thighs
(3) penis
(4) abdomen
Other complications:
(1) cellulitis
(2) thrombosis in superficial veins
(3) dermal pigmentation ("tattooing")
(4) foreign body granulomas
(5) burns from cigarettes, heaters or fires while passed out
(6) bruising
(7) area of ulceration
(8) subcutaneous scars
Attempts to mask scars:
(1) wearing long sleeved shirts in hot weather
(2) placing tattoos over dermal scars
