1. BLASCHKOID DERMATITIS

2. Introduction
• 1901: German dermatologist
Alfred Blaschko (1858-1922) ;
retrospective
• No Nervous, Vascular or
Lymphatic correspondence
• developmental growth pattern
of the skin; pattern of Ectodermal
Migration and Proliferation from
Neural Crest

3. • V-shape – Upper Back, Neck, Upper Trunk
• S-shape – Lateral Trunk
• Inverted U-shape - breast area / Upper Arms
• Perpendicular - lower extremities, Forearms
• ‘Respect the Midline’
• Koebner's phenomenon but the curvature of the lesions does not
support this hypothesis
• Less defined on the head and neck
• Happle et al  posterior scalp whereas
• Bolognia et al  lateral aspect face and neck
• Equivalent over teeth and eyes

4. • aa

5. • aa

6. Embryological Etiological basis
• No Vascular / Nervous / Lymphatic
• Jackson – localization determined by the dermal
tissues
• ? Inborn error of morphogenesis due to a single
mutant gene
• ? stretching of the skin during embryogenesis
• ? Mosaicism and Lyonization

7. • aa

8. Langer's lines / Cleavage lines, -
correspond to the natural
orientation of Collagen /
Muscle fibres.
Used in forensic science
& surgical techniques.

9. • Kraissl's lines –anatomical
Tension skin lines ; Cadavers
• Cox – Tension Skin Lines
• Borges – Relaxed TSL

10. • Voigt Lines – Pigmentary
demarcatory lines over body
; the boundaries of the
Areas of distribution of the
cutaneous nerve stems ;
attributed to hormones

11. • a

12. • aa

13. • aa

14. • aa

15. • aa

16. • h

17. THANK YOU