Yellow nail syndrome is characterized by the triad of yellow nails, lymphedema, and recurrent pleural effusions/bronchiectasis. The nail finding in yellow nail syndrome that differentiates it from onychomycosis includes:

• A Slow nail growth, absent lunula, increased transverse over-curvature, and negative fungal culture ✓
• B Nail plate thickening with subungual hyperkeratosis and positive KOH
• C Pitting and oil-spot discoloration indicating psoriatic onychopathy
• D Beau's lines indicating systemic illness

Explanation

Yellow nail syndrome shows characteristic nail changes: yellow-green discoloration, markedly slow nail growth (<0.1 mm/week vs normal 0.1 mm/day), absent or diminished lunula, loss of cuticle, increased transverse curvature (over-curvature), onycholysis, and sometimes nail shedding. KOH and fungal culture are negative, distinguishing it from onychomycosis. Pathophysiology involves lymphatic dysfunction. Associated conditions include pleural effusion, bronchiectasis, chronic sinusitis, and rheumatoid arthritis.

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.