A 58 year-old male with a history of localised prostate cancer commenced ciprofloxacin for presumed prostatitis. Two weeks later, he was referred to the dermatology service for generalised pruritic maculopapular and pustular eruption, associated with fever and liver function derangement. Based on skin biopsy findings of drug reaction with eosinophilia, fevers, liver involvement and peripheral eosinophilia, the patient fulfilled criteria for DRESS1. He was managed with high-dose oral and topical glucocorticoids and discharged on a weaning prednisolone course.
The patient represented after two weeks with exertional dyspnoea, sinus tachycardia (130 bpm) and heart failure with reduced left ventricular ejection fraction (LVEF) on echocardiogram of 33%. A CT pulmonary angiogram excluded pulmonary embolus. Troponin-I was elevated at 52ng/L (<50) accompanied by new-onset thyrotoxicosis, with a suppressed TSH <0.01 mIU/L (0.4-4.0), high fT4 >64pmol/L (9.0-19.0), fT3 22.3pmol/L (2.6-6.0) and negative TSH-receptor antibody. Thyroid ultrasound demonstrated normal vascularity and no focal lesion. Management consisted initially of carbimazole 15mg bd, which was later ceased due to suspicion of subacute thyroiditis. Gradual escalation of propranolol to 80mg tds for persistent tachycardia was titrated and transitioned to nebivolol. Serial TFTs demonstrated gradual improvement in thyrotoxicosis during admission[Fig.1]. Conversely, troponin-I increased from 52ng/L to a peak of 21,172ng/L on Day 14[Fig.1] without angina. Coronary angiogram excluded coronary artery disease, and a ventricular biopsy demonstrated eosinophilic myocarditis, satisfying two autoimmune sequelae of DRESS:subacute thyroiditis and eosinophilic myocarditis. He was managed with intravenous methylprednisolone and cyclophosphamide as a steroid-sparing agent. His heart failure, thyroid and cutaneous manifestations improved within 4-6 weeks.
The manifestations of DRESS and its autoimmune sequelae may be explained by dramatic expansions of functional T-regulatory cells during the acute phase, followed by gradual loss of function after resolution, triggering risk of autoimmune disease2. This is a rare but important condition with multi-system and endocrine manifestations.