IPF exacerbations constitute the most devastating compli cation of IPF. Diff erent and hard-to-diff erentiate clinical scenarios may reproduce the hallmark of their defi nition: subacute/acute deterioration of dyspnea and bilateral chest infi ltrates, corresponding in 'true' IPF exacerbations, to a tissue pattern of DAD upon UIP. Also, ALI/ARDS and AIP present DAD. Intensive immunosuppression proved ineff ective and represents the coup de grace for these patients. Provision of excel lent supportive care and the search for and treatment of the 'underlying cause' remain the only options. Th e unravelling of Ariadne's thread continues.