Background: Interstitial lung disease [ILD] is one of the most prevalent respiratory symptoms of connective tissue diseases [CTDs], leading to significant morbidity and death. Nailfold capillaroscopy [NFC] is the best tool for analysing microvascular disorders in CTDs since capillaroscopic alterations in the nailfold are well documented in several CTDs.  
The Aim of the work: To assess the value of Nailfold capillaroscopy examination in patients with ILD.
Patients and methods: This study involved 100 patients aged between 18 and 90 years diagnosed with ILD divided into three groups; group [I] involved 30 patients with rheumatoid arthritis [RA] associated with ILD, group [II] involved 30 patients with systemic sclerosis [SSc] associated with ILD, and group [III] included 40 patients with idiopathic ILD. In all patients, NFC was performed with clinical and laboratory assessment.
Results: According to nailfold capillaroscopic findings, patients with normal nailfold capillaroscopy were found only in idiopathic ILD. CTD-ILD group has a significantly lower mean capillary density than idiopathic ILD [p= <0.05]. Also, RA-ILD, IPF, and SSC-ILD subgroups had more severe abnormalities in capillaroscopy. The RA-ILD subgroup's capillary density was significantly lower than that of the idiopathic ILD only group. Furthermore, we found that [SSc-ILD] group had the lowest significant capillary number [ranged from 4-9/mm] & the highest significant capillary width [ranged from 29-76/μm] and the shortest significant capillary length [ranged from 75-256/μm] in comparison to the other groups.
Conclusion: We can conclude that SSc-ILD patients had more severe nailfold-capillaroscopic abnormalities than both RA-ILD and idiopathic ILD groups. Assessment of Nail should be considered during ILD examination for early detection of Nailfold abnormality to improve prognosis of the disease.