Onychoscopy: Dermoscopy of the Nail Unit

Overview / Definition Onychoscopy is a specialized dermoscopic technique designed to examine the nail unit, which includes the nail plate, nail bed, and surrounding structures. By utilizing a dermatoscope, clinicians can enhance their visualization of nail pathologies, aiding in the diagnosis of various conditions affecting the nails and surrounding tissues. Epidemiology 10% of the population may experience some form of nail pathology at some point in their lives. Conditions such as onychomycosis, psoriasis, and trauma-related changes are commonly encountered. Pathophysiology / Mechanism The nail unit consists of several components, including: Nail plate: Composed of keratinized cells, providing protection. Nail bed: The skin beneath the nail plate, which is richly vascularized. Cuticle: The tissue that overlaps the nail plate, protecting the matrix. Nail matrix: The tissue under the base of the nail, responsible for nail growth. Changes in these structures can indicate underlying systemic diseases, infections, or localized dermatological conditions. Clinical Presentation Patients with nail disorders may present with a variety of symptoms, including: Discoloration: Yellow, white, or brown discoloration can indicate various conditions. Thickening: Often seen in fungal infections or psoriasis. Separation: Onycholysis, or separation of the nail from the nail bed, can occur due to trauma or infections. Pitting: Commonly associated with psoriasis. Understanding the specific findings observed during onychoscopy can guide diagnosis and management. Diagnosis / Workup Onychoscopy enhances the diagnostic process by allowing detailed visualization of: Subungual pigmentation: Assess for melanoma or other neoplastic processes. Keratinization patterns: Differentiate between fungal and non-fungal conditions. Vascular patterns: Identify conditions like psoriasis or lichen planus. Performing a thorough history and physical examination is essential, along with potential laboratory te