7th June 2025

Pachyonychia congenita

Aetiology, epidemiology, and inheritance

• Rare disorder primarily affecting the keratinization in the skin and nails 
• Mutation in the gene sequence encoding for keratin resulting in disruption of the keratin cytoskeleton leading to the formation of weak keratin aggregates.
• 1000-10,000 people are affected with pachyonychia congenita worldwide
• Autosomal dominant inheritance

Diagnosis

• Presents usually in first few years of life and a positive family history.
• Clinical manifestations.     
  • Predominant clinical manifestations involve a triad of hypertrophic nail dystrophy, plantar keratoderma, and severe plantar pain.
  • Nail: Hyperkeratosis in the nail is usually the first manifestation. Some or all the nails can be affected. The affected nail either grows in an up-slanting way due to aggregates of keratin underneath or terminates prematurely exposing the distal nail bed.
  • Plantar keratoderma: Usually starts to manifest when the child starts weight bearing and walking. Image Source: Wikimedia Commons (2021). Planter Keratoderma, Licensed under a creative commons licence. Available for free at: https://en.wikipedia.org/wiki/Keratoderma#/media/File:Planter_keratodermaC.jpg (Accessed 22 May 2025).
  • Diffuse or focal hyperkeratosis happens causing severe pain.
  • Other lesions:
  • Oral leukokeratosis appears as grey-white patches on the oral mucosa
  • Natal/Prenatal teeth
• Histopathology
  • Accentuated and prominent keratosis seen on biopsy from plantar keratoderma lesions. On electron microscopy- aggregates of keratin are seen in the spinous layer.

Management

• Mainly focused on reducing nail and palmoplantar keratosis as well as pain management.
• General
  • Good oral hygiene in oral leukokeratosis
• Medical
  • Softening of the skin by keratolytic lesions e.g. salicylic acid, moisturizers and emollients.
  • Oral retinoids
• Surgical
  • Filing of hyperkeratotic areas by podiatry

Complications

• Plantar keratoderma associated pain-
  • Chronic plantar pain may be debilitating leaving the child with severe mobility limitations affecting his daily living.
• Oral Leukokeratosis
  • May cause feeding difficulties in children and if severe, may cause hoarseness of voice and/or acute airway obstruction.