Rash and dyspnoea in a 39 year old man

A previously well 39 year old man of Bengali origin presented with a three day history of fever, pleuritic chest pain, progressive dyspnoea, and non-productive cough. Six days previously he had developed a widespread centripetally distributed pruritic rash. He was employed as a chef and was an ex-smoker (20 pack year history); he had no history of misuse of drugs or alcohol. His only recent foreign travel was a brief visit to Bangladesh six months earlier. His wife and child had had similar rashes five days ago, although they were afebrile and systemically well.

His pulse was regular at 98 beats/min, blood pressure was 109/67 mm Hg, temperature was 38.4°C, and respiratory rate was 38 breaths/min. He was using his accessory muscles to breathe. Auscultation of the chest showed dry crackles increasing from the mid to the lower lung zones bilaterally. He had mildly tender hepatomegaly. He had several hundred widespread exanthematous vesicles, pustules, and crusted lesions on his skin, which extended into the oral cavity.

Arterial blood gas on room air showed a partial pressure of oxygen of 9.62 kPa, partial pressure of carbon dioxide of 5.45 kPa, pH of 7.44, bicarbonate of 25.3 (reference range 21-28), and base excess of 3.5 (±2). His lymphocyte count was 3.7×10⁹/L (1.0-3.5) and alanine aminotransferase was 112 U/L (0-40), but urea, creatinine, electrolytes, other liver function tests results, and full blood count parameters were within normal ranges. Chest radiography was performed (figs 1 and 2⇓ ⇓).