Background Fingerprint [FP] abnormalities are known in patients with Systemic Sclerosis [SSc]. Little has been described about their frequency, systemic associations and social impact in literature.
Objectives To study the fingerprint abnormalities in Systemic Sclerosis patients
Methods Raynaud's phenomenon [RP] was taken as the inclusion criteria. Patients with SSc [limited LcSSc and diffuse DcSSc], SSc overlap with other Connective Tissue Diseases [CTDs] and other CTDs with RP were screened for FP abnormalities using a Standardization Testing and Quality Certification (STQC) Directorate certified biometric FP scanner. FP quality assessment was done by recording The National Institute of Standards and Technology [NIST] finger print image quality [NFIQ] scores1. NFIQ's 5 levels of quality are intended to be predictive of fingerprint matching. NFIQ=1 indicates high quality samples and NFIQ=5 indicates poor quality samples. Other associated systemic features of the disease were noted. Also the social difficulties due to fingerprint abnormalities were noted. Healthy controls with no RP were included for comparison.
Results 40 consecutive patients with RP attending Rheumatology outpatient services of our institute were screened for FP abnormalities. 29 with SSc [20-DcSSc, 9-LcSSc], 8 with overlap syndromes and 1 each of SLE, Undifferentiated Vasculitis and Undifferentiated CTD. It was noted prior to screening that 19 patients experienced some difficulty in the past with biometric recognition of their FPs at various times. On screening with biometric scanner, 15 of 40 [37.5%] had FP abnormalities in the form of non recognition of at least one finger with a median of 2 [range 1–6 fingers]. Of these 15, seven had DcSSc, six had LcSSc and two with overlap syndromes. The mean NFIQ score of these 15 patients was 4.5 [poor] and the mean NFIQ scores in SSc was 3.8. Eleven [27.5%] patients could not get government Identity cards based of FP scanning, four could not avail various government benefit schemes which needed their fingerprints as identity. Sixteen [40%] had history of digital vasculopathy in the form of digital pits, digital ischemia or ulcers. PAH was found in one and eight had Interstitial lung disease. Among the 10 controls all FPs were recognized and the mean NFIQ score was 2.2 indicating a better quality of FPs.
Conclusions Fingerprint abnormalities occur frequently in patients with systemic sclerosis causing social disabilities in few. The quality of FPs in SSc patients is poor. Raynaud's phenomenon and vasculopathy are frequently associated. Documentation of this abnormality should allow the use of other biometric tools for personal identification.
E. Tabassi, C. Wilson, C. Watson, “Fingerprint Image Quality”, NIST Internal Report 7151, National Institute for Standards and Technology, 2004.
Disclosure of Interest None declared