Microbiology: A Systems Approach 4th Edition by Marjorie Kelly Cowan

Exercise 17

Critical thinking is the ability to reason and solve problems using facts and concepts. These questions can be approached from a number of angles and, in most cases, they do not have a single correct answer.
A 31-year-old male develops a severe, full-body rash after receiving penicillin. He is certain that he has never received this antibiotic in the past. Summarize the immunologic reaction that is occurring in this patient, and discuss one hypothesis that would explain why the symptoms occurred when he had never been exposed to the drug before.