What should you know about an allopurinol skin rash?

Stop taking allopurinol and contact the prescribing clinician or an urgent-care service now for instructions. Do not take another dose unless a clinician who knows about the rash specifically tells you to restart it. A photograph and a list of all recently used medicines can help the assessment.

Allopurinol can cause a drug eruption. The appearance ranges from scattered red or itchy patches to a serious reaction involving skin pain, blisters, peeling, facial swelling, fever or internal organs. A clinician must assess the pattern and timing because rashes from contact dermatitis, eczema, infection or other medicines can look similar. The urgency comes from warning signs, not from trying to judge the cause at home.

Note when the rash started, where it first appeared and whether it is spreading. Record fever, mouth or eye soreness, facial swelling, skin tenderness and any change in urine output. Bring the allopurinol container and a complete medication list, including over-the-counter products and supplements. Avoid applying a new cream that could change the rash before it is examined.

Go to an emergency department immediately for blistering or peeling skin, sores in the mouth or around the eyes, severe skin pain, facial or tongue swelling, trouble breathing, faintness, fever with a spreading rash, unusual bruising, yellow skin or eyes, or markedly reduced urine. Do not drive yourself if you feel faint or have breathing difficulty.

Ask whether the reaction should be recorded as a drug allergy, which gout treatment is appropriate instead, and what written safety information you should carry. Confirm whether blood or urine tests are needed to check organ involvement. If another medicine was started recently, ask how the clinician decided which drug was responsible and which products must remain stopped.