Life-threatening hypersensitivity pneumonitis secondary to e-cigarettes.

We report a case of hypersensitivity pneumonitis (HP) in a young person secondary to vaping. He presented with a putative diagnosis of asthma and required extracorporeal membrane oxygenationbecause of intractable respiratory failure. He developed a critical illness and steroid myopathy and required prolonged rehabilitation. Our patient fulfils diagnostic criteria for HP secondary to e-cigarettes with a positive exposure history, deterioration after skin prick testing, specific serum IgM antibodies against the implicated liquid raising the possibility that the relevant antigen was present in that liquid and radiological and histopathological features compatible with acute HP. There are two learning points. The first is always to consider a reaction to e-cigarettes in someone presenting with an atypical respiratory illness. The second is that we consider e-cigarettes as 'much safer than tobacco' at our peril. © Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.