What should you know about bullous fixed drug eruption?

A fixed drug eruption often appears as a sharply outlined red or dusky patch, sometimes with swelling, burning, or a fluid-filled blister. When the same medicine or a related medicine is taken again, the reaction may return in the same location, although additional sites can develop. The area may leave darker colouring after it settles.

Many medicines can trigger this reaction, including some pain relievers and antibiotics, but the appearance alone cannot identify the responsible drug. A careful timeline of medicines, supplements, and symptoms helps a clinician compare possible causes and exclude infections or other blistering disorders.

Contact the prescriber or a healthcare service promptly and list every product taken recently, including occasional medicines. Do not restart a suspected medicine or test it again yourself. Ask whether it should be stopped and what safe alternative is appropriate; the decision depends on the medicine and your health.

Keep the blister intact where possible, protect it with a clean non-stick dressing, and avoid friction. A clinician may recommend a topical corticosteroid for inflammation. Photographing the early appearance and keeping the medicine packaging can help with future identification.

Get urgent help for widespread blisters, skin peeling, painful raw skin, sores in the mouth or eyes, genital involvement, facial swelling, breathing difficulty, fever, or feeling faint. These features may indicate a more serious drug reaction and should not be monitored at home.

Which medicine is the most likely trigger? Should I stop it now, and what should replace it? Should this reaction be recorded in my medical file? What symptoms would make a future reaction an emergency?