Lichen planus of the nail shows characteristic nail changes. The finding of obliteration of the nail matrix with fusion of the proximal nail fold to the nail bed producing a wing-like scar is called:

• A Beau's lines
• B Onychorrhexis
• C Twenty-nail dystrophy
• D Pterygium unguis ✓

Explanation

Pterygium unguis (dorsal pterygium) is the pathognomonic nail change of lichen planus. The lichenoid infiltrate destroys the nail matrix, causing scarring that fuses the proximal nail fold skin to the underlying nail bed, forming a V-shaped scar extending over the nail plate. If untreated, it can progress to permanent anonychia. Beau's lines are transverse grooves from temporary matrix arrest; onychorrhexis means longitudinal ridging; twenty-nail dystrophy (trachyonychia) is diffuse nail roughening sometimes associated with LP but not pathognomonic.

Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.