September 14th 2005Erythromycin had been prescribed for a 15-year-old boy who complained of flulike symptoms. Twenty-four hours after starting the medication, he awakened with painful ulceration of his mouth and lips. The erythromycin was discontinued, and hydroxyzine (25 mg, three times daily) was started for possible macrolide sensitivity. His condition worsened over the next 3 days, however, and he was hospitalized when the severe oral pain made it impossible for him to tolerate food or drink. At no point had he any nausea, vomiting, diarrhea, fever, or chills.