What should you know about drug allergy itching?

Itching can occur with hives, a widespread rash or irritation without visible skin changes. The timing after a new medicine is useful, but it does not prove an allergy: illness, dry skin, contact exposures and other medicines can also cause itching. A reaction can change over time, so note where it began and whether it spread.

Write down the medicine name, when each dose was taken, when itching began, and any swelling, fever or breathing change. This information helps a clinician separate a possible allergy from other side effects and plan safer treatment.

Contact your prescriber, pharmacist or GP Consultation service before the next dose. Do not deliberately repeat the suspected medicine to see what happens. Keep its packaging and prepare a complete list of medicines, vitamins and supplements.

Use cool water, an unperfumed moisturiser and loose clothing to limit skin irritation while awaiting advice. Ask a pharmacist before using an antihistamine, especially if you already take medicines that cause drowsiness or need to drive.

Call emergency services for swelling of the mouth, lips, tongue or throat, difficulty breathing, wheezing, faintness, sudden weakness or rapidly spreading symptoms. These may indicate Anaphylaxis. Avoid driving yourself during a severe reaction.

Ask whether you should stop the medicine, what alternative is appropriate, how to record the suspected reaction and whether Allergy Testing is useful. Ask which future symptoms require emergency help.