ICD-9-CM 995.21 is a billable medical code that can be used to indicate a diagnosis on a reimbursement claim, however, 995.21 should only be used for claims with a date of service on or before September 30, 2015. For claims with a date of service on or after October 1, 2015, use an equivalent ICD-10-CM code (or codes).
A dermal inflammatory reaction produced under conditions of antibody excess, when a second injection of antigen produces intravascular antigen-antibody complexes which bind complement, causing cell clumping, endothelial damage, and vascular necrosis
Development of an inflammatory lesion a few hours after intradermal injection of antigen into a sensitized animal; the lesion results from precipitation of immune complex, which causes complement activation and tissue destruction