What should you know about metronidazole skin rash?

Notice when the rash began, where it is located, and whether it is itchy, burning, swollen, scaly, blistered, or spreading. A reaction can occur after a medicine is swallowed or applied to the skin, but timing alone cannot prove the cause.

Other possibilities include contact dermatitis from a product, atopic dermatitis, heat rash, intertrigo in a skin fold, psoriasis, ringworm, or scabies. These conditions need different treatments, so copying a cream from a previous episode can make the skin harder to assess.

Contact the prescribing clinician before taking another dose if a new rash appeared after metronidazole, particularly if it is spreading or becoming more uncomfortable. Do not apply new fragrances, exfoliants, or steroid creams unless advised. Take a clear photograph and record the dose, route, timing, and other medicines.

If the medicine was prescribed for an infection, do not silently replace it; the clinician can decide whether it should be stopped and whether another plan is needed.

Get emergency help for trouble breathing, swelling of the lips or tongue, faintness, widespread blistering, skin peeling, painful skin, mouth or eye sores, or a rash with fever. These features can signal a serious medicine reaction.

Ask whether the medicine should be paused, which features suggest a drug rash, what symptom relief is suitable, and whether the reaction should be recorded as a medication allergy.