It differs from other drug reactions in that it: a) is caused by a particular set of drugs; b) typically occurs after a delay of 2 to 8 weeks following intake of an offending drug; c) presents with a specific set of signs and symptoms (i.e. modest or extreme elevations in blood eosinophil and atypical lymphocyte counts; acute onset of a skin rash; lymphadenopathy; fever; neuralgia; and involvement of at least one internal organ such as the liver, lung, or heart; d) develops in individuals with particular genetic predispositions; and e) involves reactivation of latent viruses, most commonly human herpesvirus 6 or more rarely human herpes virus 5 (i.e. human cytomegalovirus), human herpesvirus 7, and human herpesvirus 4 (i.e. Epstein–Barr virus). These viruses usually become dormant after infecting humans but under special circumstances, such as drug intake, are reactivated and may contribute to serious diseases such as the DRESS syndrome. Pathophysiology
Eosinophils normally function to neutralize invading microbes, primarily parasites but also certain types of fungi and viruses. In conducting these functions, eosinophils normally occupy the gastrointestinal tract, respiratory tract, and skin where they produce and release on demand a range of toxic reactive oxygen species (e.g. hypobromite, hypobromous acid, superoxide, and peroxide) and also release on demand a preformed armamentarium of chemical signals including cytokines, chemokines, growth factors, lipid mediators (e.g. leukotrienes, prostaglandins, platelet activating factor, 5-oxo-eicosatetraenoic acid), and toxic proteins (e.g. metalloproteinases, major basic protein, eosinophil cationic protein, eosinophil peroxidase, and eosinophil-derived neurotoxin). These agents serve to orchestrate robust inflammatory responses that destroy invading microorganisms.
Chondrolysis [ICD Code M94.3] is the process of breakdown of cartilage. It can occur as a result of trauma (traumatic chondrolysis). Intra-articular infusions of certain local anesthetic agents such as bupivacaine, lidocaine, ropivacaine and levobupivacaine can also lead to this effect. See also
Chondritis
Osteochondritis
Relapsing polychondritis

References
External links
Chondrolysis at Radiopedia