tailieunhanh - Chapter 056. Cutaneous Drug Reactions (Part 2)

Untoward cutaneous responses to drugs can arise as a result of immunologic or nonimmunologic mechanisms. A variety of adverse reactions result from mechanisms that do not involve an immunologic process. Drug reactions are a public health problem because of their frequent occurrence, occasional severity, and impact on the use of medications. The skin is among the organs most often affected by adverse drug reactions. The list of conditions that can be triggered by medications includes nearly all dermatologic diseases. Many of these adverse reactions result from mechanisms that do not involve an immunologic process. . | Chapter 056. Cutaneous Drug Reactions Part 2 PATHOGENESIS OF DRUG REACTIONS Untoward cutaneous responses to drugs can arise as a result of immunologic or nonimmunologic mechanisms. A variety of adverse reactions result from mechanisms that do not involve an immunologic process. Drug reactions are a public health problem because of their frequent occurrence occasional severity and impact on the use of medications. The skin is among the organs most often affected by adverse drug reactions. The list of conditions that can be triggered by medications includes nearly all dermatologic diseases. Many of these adverse reactions result from mechanisms that do not involve an immunologic process. Obvious examples are pigmentary changes related to accumulation in the dermis of amiodarone antimalarials minocycline quinolones alteration of hair follicules by cytostatics and lipodystrophy associated with metabolic effects of anti-HIV medications. These side effects are mostly toxic predictable and often can be avoided at least in part by simple preventive measures. Immunologic Drug Reactions For most acute drug eruptions benign or severe accumulated data suggest an immunologic basis. In the last 10 years drug-specific T cell clones were derived from the blood lymphocytes or from skin lesions of patients with a variety of drug allergies. Since these clones had been obtained after several stimulations in vitro with the drug their relevance to explain the original manifestations of allergy can be questioned. Regardless these T cell clones brought definite evidence that drugs can be recognized as antigens by human T cells and that these T cells play a role in drug allergy. Specific clones were obtained with penicillin G amoxicillin cephalosporins sulfamethoxazole phenobarbital carbamazepine lamotrigine . many of the medications that are frequently a cause of drug eruptions. Both CD4 and CD8 clones were often obtained whatever the clinical type of eruption. Some clones produced a .