Nail Psoriasis and Other Inflammatory Nail Disorders

Nail Psoriasis - Psoriasis Pits & Picks

Common: affects up to 50% of psoriasis patients, ↑ to 80% with psoriatic arthritis.

• Nail Matrix Changes (Origin of "Pits"):
  • Pitting: Most common; irregular, deep depressions on nail surface.
  • Leukonychia: White spots/lines.
  • Crumbling of nail plate.
  • Red spots in lunula.
• Nail Bed Changes:
  • Onycholysis: Distal/lateral separation of nail plate from bed.
  • Subungual hyperkeratosis: Thickening, scaling under nail.
  • Oil drop/Salmon patch: Translucent, yellow-red discoloration.
  • Splinter hemorrhages: Longitudinal thin black lines.

⭐ The 'oil drop' or 'salmon patch' sign, a yellowish-brown discoloration under the nail plate, is highly specific for nail psoriasis.

Lichen Planus of Nails - Planus Pterygium Pointers

• Key features:
  • Longitudinal ridging & fissuring
  • Nail plate thinning
  • Sandpaper nails (trachyonychia)
  • Dorsal pterygium formation (scarring between proximal nail fold & matrix)
  • Twenty-nail dystrophy (all nails affected)
  • Anonychia (nail loss) in severe cases
• Often associated with cutaneous or mucosal lichen planus.

⭐ Dorsal pterygium, resulting from scarring between the proximal nail fold and the nail matrix, is a characteristic and potentially irreversible sign of nail lichen planus.

📌 Pterygium, Planus, Permanent scarring if severe

Alopecia Areata & Nails - Alopecia's Nail Alerts

• Nail changes in 10-50%; may correlate with alopecia severity.
• Pitting:
  • Fine, superficial, geometric (regular shallow pits).
  • "Scotch plaid" pattern (grid-like).

  ⭐ The most common nail finding in alopecia areata is fine, superficial, geometric pitting, often arranged in a grid-like or 'scotch plaid' pattern.

• Trachyonychia:
  • Rough, "sandpaper" nails (often all 20 nails).
• Other: Beau's lines, koilonychia, red lunulae. oka

Other Inflammatory Nail Disorders - Rare Nail Ruffians

Inflammatory Nail Dx & Tx - Nail Clues & Cures

*   **Dermoscopy:** Enhances visualization.
*   **Nail Biopsy:** For diagnostic uncertainty. Matrix (matrix pathology) vs. Bed (plate/bed issues).

• Management Principles:
  • Topical: Corticosteroids, calcineurin inhibitors, Vit D analogs (psoriasis).
  • Intralesional: Corticosteroids.
  • Systemic (severe): Methotrexate, cyclosporine, retinoids, biologics.

⭐ Nail biopsy, particularly a punch biopsy of the nail matrix for suspected matrix pathology or nail bed for plate abnormalities, is the gold standard for diagnosing ambiguous inflammatory nail disorders but carries a risk of scarring.

High‑Yield Points - ⚡ Biggest Takeaways

• Nail psoriasis: Pitting (most common), onycholysis, subungual hyperkeratosis, oil drop/salmon patch are classic.
• Lichen planus: Features longitudinal ridging, pterygium formation, and nail plate thinning/atrophy.
• Trachyonychia (20-nail dystrophy): Rough, opaque, sandpaper nails; linked to alopecia areata, LP, psoriasis.
• Darier's disease: Shows distal V-shaped nicks and longitudinal red/white streaks (bands).
• Alopecia areata: Associated with geometric pitting (grid-like pattern) and trachyonychia.
• Pustular psoriasis: Causes severe nail destruction, onycholysis (e.g., Acrodermatitis continua of Hallopeau).