Palmoplantar Psoriasis

Intro & Epi - Defining the Dots

• Definition: Chronic inflammatory dermatosis of palms & soles.
  • Variants:
    • Non-pustular (Hyperkeratotic): Well-demarcated, erythematous, scaly plaques; painful fissures common.
    • Pustular (Palmoplantar Pustulosis - PPP): Crops of sterile, yellow-brown pustules on erythematous base.
• Epidemiology:
  • Affects ~3-5% of psoriatic patients.
  • Onset: Bimodal (20-30s & 50-60s); PPP often later.
  • PPP: Predominantly females (F:M ≈ 9:1).
• Key Associations:
  • Smoking: Very strong link, esp. for PPP (📌 Smoking Predisposes Pustules).
  • Other psoriasis types (e.g., plaque psoriasis).
  • Psoriatic Arthritis (PsA).

  ⭐ Up to 95% of Palmoplantar Pustulosis (PPP) patients are current or former smokers.

Clinical Features - Palms & Soles on Fire

• Appearance:
  • Sharply demarcated, erythematous plaques.
  • Thick, silvery-white, adherent scales.
  • Marked hyperkeratosis (thickened skin).
  • Painful fissures and cracks are common.
  • Sterile pustules may be present (palmoplantar pustulosis variant).
• Distribution & Extent:
  • Typically bilateral on palms and/or soles.
  • May involve digits, leading to psoriatic dactylitis ("sausage digits").
• Key Symptoms:
  • Significant pain and tenderness.
  • Intense pruritus.
  • Functional impairment (difficulty walking, using hands).
• Associated Nail Changes:
  • Frequent: Pitting, onycholysis, subungual hyperkeratosis, oil-drop sign.

⭐ Palmoplantar pustulosis (PPP), a variant of palmoplantar psoriasis, shows a very strong association with smoking, especially in women.

DDx & Dx - Spot the Impostor

Key DDx:

• Dx:
  • Mainly clinical.
  • Biopsy (HPE): Acanthosis, parakeratosis, Munro's microabscesses. Kogoj's pustules (pustular).
  • KOH Smear: Excludes tinea.

⭐ Munro's microabscesses (neutrophils in stratum corneum) are key HPE findings in psoriasis.

Management - Soothing the Scales

• General measures: Emollients, keratolytics (salicylic acid, urea), avoidance of trauma/irritants.
• Topical therapy:
  • Potent corticosteroids (e.g., clobetasol propionate) often under occlusion.
  • Vitamin D analogues (calcipotriol, calcitriol).
  • Tazarotene.
  • Coal tar.
• Phototherapy:
  • PUVA (topical or systemic).
  • NBUVB (less effective due to skin thickness).
• Systemic therapy (for severe/recalcitrant cases):
  • Acitretin (often first-line, e.g., 0.25-0.5 mg/kg/day).
  • Methotrexate.
  • Cyclosporine.
  • Biologics:
    • TNF-α inhibitors (e.g., infliximab/adalimumab).
    • IL-17 inhibitors (e.g., secukinumab/ixekizumab).
    • IL-23 inhibitors (e.g., guselkumab/risankizumab).

⭐ Acitretin is a key systemic agent for palmoplantar psoriasis; strict contraception mandatory due to teratogenicity; monitor LFTs & lipids.

High‑Yield Points - ⚡ Biggest Takeaways

• Well-demarcated, erythematous plaques with thick, yellowish-white, adherent scales on palms and soles.
• Often symmetrical, leading to painful fissures and significant functional disability.
• Can be an isolated finding or associated with psoriasis elsewhere (nails, joints, scalp).
• Auspitz sign is frequently absent or difficult to elicit due to thick hyperkeratosis.
• Important differentials include hyperkeratotic eczema, tinea manuum/pedis, and Reiter's disease.
• Management: Potent topical corticosteroids, keratolytics, vitamin D analogues; systemics for severe disease.