When to worry about a skin rash with a drug rash

A drug rash may appear after starting, stopping, or changing a medicine, although timing alone cannot identify the cause. It can look like flat or raised red spots, itching, hives, or more widespread inflammation. Fever, facial swelling, skin tenderness, blistering, peeling, mouth or eye sores, or involvement of several body areas can signal a severe reaction. Some rashes are caused by infection or another condition, so examination and a complete medicine history are valuable.

Write down every prescription medicine, over-the-counter product, supplement, and recent dose change, including when each was started. Contact the prescriber or a pharmacist promptly before making changes to an essential medicine; they can tell you whether it should be withheld or replaced. Do not take another dose of a suspected non-essential medicine without advice, and do not restart it to see whether the rash returns. Photograph the rash in good light.

Seek same-day medical advice for a new rash with fever, facial swelling, painful skin, rapid spread, or symptoms involving the mouth, eyes, or genitals. Go to emergency care for trouble breathing, throat tightness, faintness, widespread blistering, skin peeling, or feeling severely unwell. Bring the medicine packaging or an accurate medication list, and mention any previous drug reactions.

Could this be a medicine reaction or another cause? Which dose should I take next? Should this medicine be recorded as an allergy? What alternatives are available, and which symptoms require emergency care?