Assessment of the underlying disease (RA, CTD, other systemic disease) vs. drugs as regards the cause of the ILD is critical (PMID 24127020, 24205507, 24231065, 24570384). For those ILD cases exposed to methotrexate and/or other DMARDs causality assessment can be difficult if at all possible. See under specific drugs. Risk of drug-associated/induced infection highest with steroids, and/or TNF antagonists