question: Just saw a patient (11yo) prescribed cephalexin for 10 days for cellulitis of toe 5/31/14. Sensitivities included cefazolin but not cephalexin. Can these drugs be used interchangeably? Child presents today with scattered maculopapular rash and red skin with hot flashes , malaise since yesterday. Am wondering if this is a drug vs staph infection rash. She looks ill. Did not do vitals or examine as knew needed more evaluation than available in retail clinic.