A client who began taking allopurinol 5 days ago reports a new widespread rash with peeling skin and painful sores in the mouth. Which instruction should the nurse provide?

Allopurinol should be stopped at the first sign of a rash. Peeling skin and oral sores raise concern for a severe cutaneous reaction, so the client needs immediate medical evaluation rather than self-treatment or dose adjustment.

Quick answer
Stop allopurinol and seek immediate evaluation. The skin peeling and oral sores suggest a potentially severe drug reaction.

Why this is correct
Allopurinol can cause serious hypersensitivity and severe skin reactions. The prescribing information directs discontinuation at the first appearance of a rash, and mucosal involvement or peeling increases the urgency of assessment.

Easy analogy or mental picture
A new rash on allopurinol is like smoke from an electrical panel: disconnect the source and investigate promptly. The picture emphasizes early action, but it does not diagnose the exact reaction or replace emergency clinical assessment.

Memory hook
Allopurinol plus a new rash means stop the drug and evaluate promptly.

NCLEX decision rule
When a medication is associated with severe cutaneous reactions and a client reports a new rash, follow the drug-specific stop instruction and escalate concerning features. Do not advise unsupervised rechallenge or dose reduction.

Why the other choices are wrong
An antihistamine or moisturizer can mask symptoms while the reaction progresses. Briefly skipping and then restarting exposes the client again, and waiting for fever delays evaluation of already serious findings.