 However, there is a complex interplay between a patient's inherited genetics, the pharmacotoxicology of the drug and the immune response that ultimately give rise to the manifestation of a drug eruption.Because the manifestation of a drug eruption is complex and highly individual, there are many subfields in medicine that are studying this phenomenon.For example, the field of pharmacogenomics aims to prevent the occurrence of severe adverse drug reactions by analyzing a person's inherited genetic risk.