Microbiology Fundamentals 2nd Edition by Jennifer Bunn,Marjorie Kelly Cowan

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C A S E F IL E

Not What We Were Expecting
I was working in a pediatric hospital in the emergency room. A 2-year-old girl with an obvious rash was brought in by her mother, who wondered whether the rash might be chickenpox.
I took the child and her mother back to a cubicle and began to take the child's history. The child was healthy and had no major health problems. Her vaccinations were all current, including the chickenpox vaccine, which made a diagnosis of chickenpox unlikely. She had recently had otitis media, an ear infection, and was on her second-to-last day of antibiotic therapy with Ceclor, a cephalosporin antibiotic. The child had taken Ceclor on one other occasion for an ear infection.
The vital signs were normal. She did not have a fever. The rash was maculopapular, a fl at red rash with tiny pimplelike eruptions in the center. The rash covered her face, chest, back, arms, and legs. In fact, it covered almost her entire body except the palms of her hands and soles of her feet. The child was clearly uncomfortable and was scratching exposed areas of skin.
The mother reported that she had taken the child for a haircut in the afternoon and noticed a few spots on the child's neck. She did not think much of the spots at the time. She dropped the little girl off at her mother-in-law's for child care while she went to work as a waitress. When she returned to her mother-in-law's house to pick the child up after her shift, the child was awake, irritable, and covered in the rash. Alarmed, the mother brought the child immediately to the emergency room.
After recording the history and the child's vital signs, I went to find the physician and reported my findings. He told me that he felt he knew what the problem was but would quickly examine the child first before telling me his diagnosis. The doctor looked at the patient's rash and told the mother, "Just as I thought. The rash is a reaction to the Ceclor your daughter has been taking. Stop the Ceclor and the rash will go away." The mother was surprised because she had always thought that an allergic reaction to a drug would start with the first dose. The physician told her that an allergic reaction could begin at any time, even after taking the same drug numerous times.
The child's ears were checked and there was no sign of infection. The girl and her mother were discharged after receiving a prescription for an antihistamine to help control the itching.
• What category of antibiotic does Ceclor fall under?
• What is the mechanism underlying the allergic response to an antibiotic?