Nail Psoriasis

Nail Psoriasis: Introduction - Nails Under Siege

• Chronic inflammatory condition affecting fingernails and/or toenails.
• Common manifestation of psoriasis; can occur with or without skin lesions.
• May be the only sign of psoriasis in some individuals.
• Significantly impacts quality of life and dexterity.

⭐ High prevalence of nail psoriasis (up to 80-90%) in patients with psoriatic arthritis (PsA).

Nail Psoriasis: Pathophysiology - Root Of The Problem

• Psoriatic inflammation of specific nail unit structures underlies diverse nail changes.
• Nail Matrix (Root): Inflammation here causes:
  • Pitting (most common)
  • Leukonychia (white spots)
  • Beau's lines (transverse grooves)
  • Trachyonychia (rough nails)
  • Nail plate crumbling
• Nail Bed (Under Plate): Inflammation results in:
  • Oil drop sign (salmon patch)
  • Splinter hemorrhages
  • Onycholysis (distal separation)
  • Subungual hyperkeratosis
• Hyponychium (Under Tip): Involvement leads to:
  • Onycholysis
  • Subungual hyperkeratosis

⭐ Nail matrix involvement typically causes pitting and nail plate deformities, while nail bed involvement leads to oil drop sign and onycholysis.

Nail Psoriasis: Clinical Features - Spot The Signs

• Nail Matrix Signs (Plate Formation):
  • Pitting: Most common; irregular, deep depressions.
  • Leukonychia: White discoloration.
  • Red spots in lunula.
  • Crumbling of the nail plate.
  • Beau's lines: Transverse grooves.
• Nail Bed Signs (Plate Adherence & Underneath):
  • Oil drop/Salmon patch: Translucent, yellow-red spot.

    ⭐ The 'oil drop' or 'salmon patch' sign is a highly characteristic feature of nail bed psoriasis.

  • Splinter hemorrhages: Linear black streaks.
  • Onycholysis: Distal/lateral nail separation from bed.
  • Subungual hyperkeratosis: Thickening, debris under nail.
• Overall Nail Changes:
  • Trachyonychia: Rough, sandpaper-like nails (less common).

Nail Psoriasis: Diagnosis & DDx - Nail It Down

• Diagnosis: Primarily clinical (psoriasis history, characteristic nail signs like pitting, onycholysis, oil spots, subungual hyperkeratosis). Dermoscopy aids visualization. Biopsy rarely needed.
• Key DDx & Differentiation:
  • Onychomycosis: KOH microscopy, fungal culture crucial.
  • Lichen Planus: Dorsal pterygium, longitudinal fissuring.
  • Alopecia Areata: Geometric (grid-like) pitting.
  • Traumatic Onychodystrophy: History of trauma.
  • Eczematous Nail Dystrophy: Associated dermatitis.

⭐ Onychomycosis is the most important differential diagnosis for nail psoriasis; KOH examination is key to differentiate.

Nail Psoriasis: Severity Assessment - Gauging Damage

• Purpose: Quantify damage, guide treatment, monitor response.
• Key Tool: Nail Psoriasis Severity Index (NAPSI).
  • Nail divided into quadrants.
  • Assesses matrix & bed psoriasis features.
  • Score example: 0-80 (10 nails).
• Modified NAPSI (mNAPSI) also used.

⭐ The Nail Psoriasis Severity Index (NAPSI) is a commonly used tool to objectively assess and monitor disease severity.

Nail Psoriasis: Management - Taming The Nails

• General Measures: Nail care, avoid trauma, camouflage.
• Approach: Stepwise, based on severity & patient factors.
• Mild-Moderate Disease:
  • Topical: High-potency corticosteroids (e.g., clobetasol), calcipotriol, tazarotene.
  • Intralesional steroids (e.g., triamcinolone acetonide 2.5-10 mg/mL).
• Moderate-Severe/Refractory Disease:
  • Systemic: Methotrexate, cyclosporine, acitretin.
  • Biologics: TNF-α inhibitors, IL-17 inhibitors, IL-23 inhibitors.

⭐ Biologic agents (e.g., TNF-α inhibitors, IL-17/IL-23 inhibitors) are highly effective for severe or refractory nail psoriasis, often used when systemic disease also requires treatment.

High‑Yield Points - ⚡ Biggest Takeaways

• Pitting is the most common manifestation of nail psoriasis.
• Onycholysis, or distal nail bed separation, is frequently seen.
• The "oil drop" sign (salmon patch) is pathognomonic.
• Subungual hyperkeratosis leads to nail thickening and crumbling.
• Nail psoriasis is strongly associated with psoriatic arthritis (PsA), especially involving DIP joints.
• Nail involvement can be the sole presenting feature of psoriasis.
• Management includes topical corticosteroids, vitamin D analogs, and systemic therapies for severe cases.