Presumed pathogenesis: ischemic necrosis caused by arterial vasospasm and/or thrombosis and/or drug embolism
Clinical features:
(1) history of recent intramuscular injection of a drug
(2) onset of acute pain at the injection site with pain and edema
(3) circumscribed area of livedoid dermatitis
(4) development of aseptic necrosis that may involve skin, subcutaneous tissue and/or muscle
(5) progression to scar if left untreated
A skin biopsy shows thrombosis of small and medium-sized blood vessels.
Differential diagnosis:
(1) abscess at the injection site
(2) hematoma at the injection site
Management may include:
(1) injection of heparin and corticosteroids at the injection site (early)
(2) surgical debridement of the necrotic tissue (late)
