<unk>  are a group of potentially lethal<unk>  drug<unk>  that involve the skin and mucous membranes of various body openings such as the eyes, ears, and inside the nose, mouth, and lips. In more<unk>  cases, SCARs also involves serious damage to internal organs. SCARs includes five syndromes: Drug<unk> with eosinophilia and systemic symptoms (i.e. DRESS syndrome, also termed Drug-induced hypersensitivity syndrome DIHS); Stevens–Johnson syndrome (SJS); Toxic epidermal necrolysis (TEN), Stevens-Johnson/toxic epidermal necrolysis overlap syndrome (SJS/TEN); and Acute generalized exanthematous pustulosis (AGEP). The five disorders have similar pathophysiologies, i.e. disease-causing mechanisms, for which new strategies are in use or development to identify individuals predisposed to develop the SCARs-inducing effects of specific drugs and thereby avoid treatment with them. Maculopapular rash (MPR) is a less-well defined and benign form of drug-induced<unk>  skin<unk> ; while not classified in the SCARs group, it shares with SCARS a similar pathophysiology and is caused by some of the same drugs which cause SCARs.<unk>  drug<unk>  are major therapeutic problems estimated to afflict up to 20% of inpatients and 25% of outpatients. About 90% of these<unk><unk>  take the form of benign morbilliform rash hypersensitivity drug<unk>  such as MPR. However, they also include more serious<unk> : a) pseudo-allergic<unk>  in which a drug directly stimulates mast cells, basophils, and/or eosinophils to release pro-allergic mediators (e.g. histamine); b) Type I, Type II, and Type III hypersensitivity<unk>  of the adaptive immune system mediated by IgE, IgG, and/or IgM antibodies; and c) SCARs and MPR which are Type IV hypersensitivity<unk>  of the innate immune system initiated by lymphocytes of the T cell type and mediated by various types of leukocytes and cytokines. Type IV hypersensitivity<unk>  are off-target drug<unk> , i.e.<unk>  in which a drug causes toxicity by impacting a biological target other than the one(s) for which it is intended. They are T cell-initiated delayed hypersensitivity<unk>  occurring selectively in individuals who may be predisposed to do so because of the genetically-based types of human leukocyte antigens (i.e. HLA) or T-cell receptors they express; the efficiency with which they absorb, distribute to tissues, metabolize, and eliminate a drug or drug metabolite; or less well-defined idiosyncrasies. SCARs are here considered as a group focusing on the similarities and differences in their pathophysiologies, clinical presentations, instigating drugs, and recommendations for drug avoidance. Further details on these syndromes can be found on their individual Wikipedia pages.
Severe cutaneous adverse reactions
Chronic toxicity
Acute toxicity
Progressive disease
Autoimmune/inflammatory syndrome induced by adjuvants
Serious Hazards of Transfusion
Allergies in children
Limited symptom attack