<dermatology> A rash that results from an allergic response, most often secondary to a drug. The rash is described as pink-red macules (flat), that may have clear centres (iris lesions) or appear as a dusky violet colour.
Erythema multiforme most often results from reactions to sulpha drugs, penicillin's, phenytoin, barbiturates, phenolphthalein and carbamazepine. In some cases, erythema multiforme can result secondary to a Herpes simplex infection or Mycoplasma infection.