Evaluation of Subclinical Nail changes in Patients with Chronic Plaque Psoriasis using Dermoscopy

Abstract

Abstract Background Dermoscopy is a non-invasive technique that allows the visualization of subtle clinical features of the skin surface and appendages details not visible to the naked eye, allowing magnifications of up to 200x. It is widely used for evaluating and diagnosing all nail diseases, as it provides important information. As any other examination, nail dermoscopy (onychoscopy) requires a good knowledge of nail anatomy & physiology and the pathogenesis of the nail diseases, and it is helpful for the diagnosis of numerous nail diseases and tumors. Nail disorders are defined according to their appearance and the part of the nail affected (from distal to proximal): hyponychium, onychodermal band (ODB), nail bed, nail plate, lateral nail folds (perionychium), lunula (distal part of the matrix), cuticle, nail matrix and proximal nail fold. Objective To study the dermoscopic findings of subtle nail changes in patients with chronic plaque psoriasis and compare it with that nail changes in healthy controls by both polarized and non polarized mode of dermoscope, aiming to assist clinicians in correctly evaluating and diagnosing nail changes with the help of dermoscopy. Methods We conducted a comparative descriptive study on 50 patients having chronic plaque psoriasis, 26 were males (52.0%) and 24 were females (48.0%), as well as 50 normal healthy control subjects, 31 were males (62.0%) and 19 were females (38.0%). Patients and controls were randomly recruited from the outpatient clinic of dermatology department at Ain Shams University Hospitals, during the period from February 2018 till September 2018. And the age of both groups ranged from 14 to 70 years. Results Our study revealed that the most common fingernail changes found in psoriatic patients were nail plate thickening and crumbling followed by Dilated nailbed capillaries at the onychodermal band, Oncholysis, Subungual hyperkeratosis, Pitting, Longitudinal ridges, Scales, Salmon patch, Leukonychia, Splinter hemorrhage, Lunula red spot and Trachyonychia. And the most common toenail changes found in psoriatic patients were Subungual hyperkeratosis followed by Nail Plate Thickening &Crumbling, Oncholysis, Pitting, Longitudinal ridges, Scales, Salmon patch, Trachyonychia, Dilated nailbed capillaries at the onychodermal band, Splinter hemorrhage, Leukonychia and Lunula red spot. We found there was no difference between polarized and non polarized mode of dermoscope in examination of fingernails and toenails except that the non polarized mode showed the changes of the Dilated capillaries at the onychodermal band more obviously. And also, there was no difference between wet and dry method of polarized mode of dermoscope. Conclusion This study confirms that a handheld dermoscope is a very efficient and simple tool for detection of any nail abnormality.