In the physiopathology of a new-onset headache, the exact mechanisms may be multiple, complex and not always well known. Peripheral nociceptive structures and central sensitisation mechanisms may be involved in their development.15 16 The current International Headache Classification proposes, generically for secondary headaches, that the diagnostic criteria do not require remission or improvement of the underlying causal disorder before the diagnosis is formalised. For acute processes, a close temporal relationship between the onset of the headache and the onset of the suspected causal disorder is usually sufficient.11 Following this classification, mask-associated headache would probably be a multifactorial disorder with unknown aetiopathogenesis at present. Hypothetically, a number of factors may explain the association with filter mask use, including hypoxia, hypercapnia, local compression and mechanical phenomena, as well as anxiety about wearing the device.10