reflux and peptic ulcer), Strontium ranelate (osteoporosis treatment), Chinese herbal medicine. Medications associated with the development of DRESS are often popular, widely used, and/or clinically important for the control of certain diseases. This is evident in the most commonly cited medications that cause the DRESS viz., allopurinol, sulfasalazine, and minocycline, as well as in prominent but less commonly cited causes of the disorder such as strontium ranelate, leflunomide, dapsone, and nonsteroidal anti-inflammatory drugs (diclofenac, celecoxib, ibuprofen, and phenylbutazone). Genetics Studies have found that certain populations that express particular serotypes (i.e. alleles) of HLA-A, HLA-B, and/or HLA-C have an increased risk of developing the DRESS syndrome in response to specific medications. These associations include the following: Carbamazepine: Chinese, Koreans, Japanese, and European individuals who express the HLA serotype (i.e. allele) termed HLA-A31:01 have a low (~1%) but far higher risk of developing the syndrome in response to carbamazepine than those not expressing it. Japanese expressing the serotypes HLA-A11 or HLA-B51 also have increased risks of developing it in response to Carbamazepine. Phenytoin: Han Chinese individuals expressing HLA-B13:01, HLA-B51:01, HLA-B15:02, HLA-Cw*08:01, or HLA-DRB1*16:02 serotypes have higher risks of developing the syndrome in response to phenytoin. Dapsone: Han Chinese individuals expressing the HLA-B13:01 serotype have a higher risk (7.8%) of developing the DRESS syndrome in response to dapsone. Allopurinol: Han Chinese, Korean, Thai, and European individuals expressing the HLA-B58:01 serotype have a higher incidence of developing the syndrome in response to allopurinol. Nevirapine: Africans, Asians, and Europeans expressing HLA-DRB1:01:01 or HLA-DRB1:01:02, or HLA-Cw4 serotypes, Asians expressing the HLA-B35 serotype and Australians and Europeans expressing the HLA-C04 serotype have higher incidences of developing the syndrome in response to nevirapine. Abacavir: European and African individuals expressing the HLA-B57:01 serotype have a higher incidence (55%) of developing the syndrome in response to abacavir. Vancomycin: European individuals carrying HLA-A*32:01 have an approximately 20% chance of developing DRESS syndrome after ≥ 2 weeks of vancomycin Pathophysiology Human leukocyte antigens Like other drug-induced SCARs disorders, the DRESS syndrome is a type IV hypersensitivity reaction in which a drug or its metabolite stimulates cytotoxic T cells (i.e. CD8+ T cells) or T helper cells (i.e. CD4+ T cells) to initiate autoimmune reactions that attack self tissues. DRESS syndrome is a SCARs type IV, subtype IVb reaction. This contrasts with SJS, SJS/TEN, and TEN which are type IV, subtype IVc reactions and AGEP which is a type IV subtype IVd reaction.