 As such, there are clinical examples of inherited genetic alleles that are known to predict drug hypersensitivities and for which diagnostic testing is available.Some of the most severe and life-threatening examples of drug eruptions are erythema multiforme, Stevens–Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), hypersensitivity vasculitis, drug induced hypersensitivity syndrome (DIHS), erythroderma and acute generalized exanthematous pustulosis (AGEP).These severe cutaneous drug eruptions are categorized as hypersensitivity reactions and are immune-mediated.