7th June 2025

Diagnosis

Diagnosis of ichthyosis is usually clinical diagnosis, based on history and examination findings.

History

• Onset after birth/early childhood
• Possible improvement with age, warm weather 
• Family history
• Associated atopic diseases

Examination                

• Distribution
  • Most commonly in the trunk and extensor extremities. Usually spares the skin folds (e.g. neck, axilla, elbow and knee crease)
• Morphology:
  • Scales: White/Grey fine scales 
  • Palmar hyper linearity: Pronunciation of major fissures as well as fissures on thenar eminence. Increase in minor fissures.
  • Keratosis pilaris: Rough, small bumps on the surface of the skin.
• For associated diseases Image Source: Wikimedia Commons (2017). Ichthyosis, Licensed under a creative commons licence. Available for free at: https://en.wikipedia.org/wiki/Ichthyosis#/media/File:Ichthyosis_(1).jpg (Accessed 22 May 2025).
• Corneal affection
• Atopic diseases

Histopathology

• Clinical diagnosis is usually sufficient
• Biopsy is usually taken from the extensor part of the arm/shin and shows a markedly reduced/absent granular layer in the epidermis. Electron microscopy shows abnormal keratohyalin granules.