Skin rash due to antibiotics: what to know

A medicine-related rash can appear as itchy pink or red patches, raised spots or widespread hives. It may begin soon after a dose or later during the course. The original infection can also cause fever and skin changes, and viral illnesses sometimes produce a rash while an antibiotic is being taken. A dangerous reaction may involve blistering, peeling skin, painful sores, fever, facial swelling or problems affecting the mouth, eyes or genitals. The exact antibiotic, dose, timing and appearance matter.

Contact the prescriber or pharmacist as soon as you notice a new rash. Keep the medicine packet and write down the dose, the time of the last dose and any other medicines taken. Do not take another dose until you have received clear advice when allergy is suspected, unless a clinician has specifically told you to continue. Do not label yourself allergic based only on a rash; a clinician can document the reaction and choose a safe treatment plan.

Call emergency services immediately for breathing difficulty, throat or tongue swelling, faintness, wheezing or widespread hives with weakness. Go to urgent care for blistering, peeling, skin pain, a rapidly spreading rash, high fever, confusion, or sores in the mouth or eyes. Bring the antibiotic and a list of all medicines. Do not wait for the next scheduled dose if severe symptoms are present.

Does this look like an allergy, an infection-related rash or another skin problem? Should I stop or change the antibiotic? Which related medicines should be avoided? How should this reaction be recorded for future prescriptions?