Synopsis
Recognise delayed drug reaction with eosinophilia and systemic symptoms, withdraw the likely culprit promptly, assess organ involvement serially, and prevent dangerous re-exposure.
- Suspect DRESS when a widespread drug eruption appears two to eight weeks after exposure with fever, facial oedema, nodes, eosinophilia or organ injury.
- Examine for infiltrated oedema, especially face and ears, but recognise active erythema may appear violaceous, grey or brown in deeply pigmented skin.
- List every medicine taken during the preceding two months, including antibiotics already completed and dose escalation of long-term treatments.
- Use a validated framework such as RegiSCAR to structure probability, while treating urgent organ disease before the score is complete.
- Check FBC with differential, blood film, liver, renal and urinalysis, then add cardiac, pulmonary or pancreatic tests from symptoms and repeat serially.
- Systemic corticosteroid decisions and taper are specialist-led because organ severity varies and relapse can follow rapid reduction.
- DRESS syndrome must be assessed by lesion duration, onset, distribution, symptoms, mucosal findings, systemic physiology and the full medicine timeline rather than by colour alone.
- For DRESS syndrome, document the working diagnosis, excluded emergencies, uncertain culprit or trigger, treatment response and the exact safety-net given.
Key red flags
Jaundice, coagulopathy, chest pain, breathlessness, hypotension, reduced urine output, confusion, severe abdominal pain or rapidly worsening blood tests requires urgent critical and organ-specialist care.
Jaundice, renal change, breathlessness, chest pain, hypotension or neurological symptoms can indicate life-threatening visceral disease.
Investigation priorities
Rank plausible culprits using exposure dates, known latency, dose and organ phenotype.
Management branches
A delayed drug eruption includes fever, facial oedema, blood abnormalities or any internal-organ signal.
- Stop plausible non-essential culprits, admit when systemic involvement is significant and obtain dermatology plus acute-medical review.
- Apply a structured diagnostic framework and assess blood, liver, kidney, urine and symptom-directed cardiac, lung or pancreatic involvement.
- Record baseline physiology and serial laboratory values because deterioration can occur after the medicine is withdrawn.