of internal organ involvement. Liver involvement is detected by measuring blood levels of alanine aminotransferase (ALT), a marker of hepatocyte injury, and alkaline phosphatase (ALP), a marker of bile duct injury, to define three types of injury: hepatocellular (elevated ALP, high ALT/ALP ratio of greater than 5), cholestatic (high ALP, low ALT/ALP ratio of less than 2), and mixed (elevated ALT and ALP, ALT/ALP ratio between 2 and 5, the cutoff values for cholestatic and hepatocellular injury, respectively). Renal involvement is more prone to occur in older individuals and in those with prior kidney or cardiovascular disease; it may take the form of severe interstitial nephritis, acute tubular necrosis, or vasculitis and may lead to kidney failure and, uncommonly, be lethal. Lung involvement takes the form of interstitial pneumonitis, pleuritis, or the acute respiratory distress syndrome; minocycline and abacavir are the main culprit drugs causing severe lung involvement. However, lung involvement in this disorder typically resolves. Cardiac involvement usually presents with evidence of left ventricular dysfunction and ECG changes; it occurs more often in individuals taking minocycline, ampicillin, or sulfonamides, and is either a cardiac hypersensitivity reaction classified as an eosinophilic myocarditis which generally resolves or a far more serious acute necrotizing eosinophilic myocarditis which has a mortality rate of more than 50%. Neurological manifestations of the DRESS syndrome include headache, seizure, coma, and motor dysfunction due to meningitis or encephalitis. Rare manifestations of the disorder include inflammation of the pancreas, gastrointestinal tract, and spleen. The following table gives the percentages for organ involvement and blood abnormalities found in individuals with the DRESS syndrome based on various studies. There are large variations in the percentages found in different studies and populations. No gold standard exists for diagnosis, and at least two diagnostic criteria have been proposed viz., the RegiSCAR criteria and the Japanese consensus group criteria. These two sets of criteria are detailed in the following table. Causes Medications Drugs that commonly induce DRESS syndrome arranged according to intended clinical action include the following: Anticonvulsants: Carbamazepine, lamotrigine, phenobarbital, phenytoin, oxcarbazepine, gabapentin, primidone Antibacterial: Amoxicillin, ampicillin, azithromycin, levofloxacin, minocycline, piperacillin/tazobactam combination, vancomycin, streptomycin Anti-tubercular: Ethambutol, isoniazid, pyrazinamide, rifampin Anti-retroviral: Abacavir, nevirapine Anti-hepatitis C: Boceprevir, telaprevir Anti-inflammatory: Acetaminophen, diclofenac, celecoxib, ibuprofen Sulfa drugs: Dapsone, sulfamethoxazole-trimethoprim combination, sulfasalazine Anticancer drugs: Sorafenib, vismodegib, vemurafenib, imatinib, Other drugs: Allopurinol (inhibits uric acid production; treatment for gout), mexiletine (treatment for heart arrhythmias), omeprazole (treatment for gastroesophageal