Onychoscopic features of nail in chronic plaque psoriasis: A cross-sectional study of 100 patients

Background: Nail involvement is a feature of 30%–50% of psoriasis patients. Only 5%–10% of patients have isolated nail psoriasis. Examination of the nail unit using a dermoscope is known as onychoscopy. The usefulness of onychoscopy in the early detection of nail psoriasis needs to be evaluated. Objective: The objective of this study was to describe the onychoscopic features in chronic plaque psoriasis patients. Materials and Methods: In this cross-sectional study, 100 patients with chronic plaque psoriasis were recruited. Onychoscopy was performed, and results were compared with the same age- and sex-matched controls. The various onychoscopic features were assessed using the Chi-square test (P < 0.05 was considered significant). The statistical analysis was done using the application named Epi Info™. Results: Out of 100 psoriasis patients, 39 patients showed clinically evident nail involvement on the naked eye, whereas 64 patients showed nail involvement on onychoscopic examination. The mean age of patients observed in our study was 37.5 years. Out of 64 patients, 43 were male and 21 were female. Pitting was the most common finding seen in 55 (85.93% and P = 0.0001) patients, followed by transverse groove in 18 (28.12% and P = 0.025), subungual hyperkeratosis in 16 (25% and P = 0.035), nail plate crumbling in 16 (25% and P = 0.0009), and oil drop sign in 8 (12.5% and P = 0.010) patients. Only these five parameters were statistically significant. Furthermore, other findings observed were onycholysis in 7 (10.93% and P = 0.166), leukonychia in 12 (18.75% and P = 0.614), splinter hemorrhages in 8 (12.5% and P = 0.099), pseudo-fiber sign in 4 (6.25% and P = 0.127), lunular red spots in 3 (4.68% and P = 0.242), and dilated globose vessels were seen in 4 (6.25% and P = 0.127) patients. Conclusion: Onychoscopy is a useful noninvasive method to detect subclinical nail involvement, which may not be visible to the naked eye.