Vascular purpura.. Increased intravascular pressure. Shrinking vessel wall. Small vessel blockage of the platelets. Blood clotting

Vascular psoriasis:
Psoriasis without thrombocytopenia constitutes most cases of porphyria.
Blood may leak due to:
- Vascular damage.
- Increased intravascular pressure.
- Deficiency of vascular blood: Bleeding may result from disorder in one or more of the following mechanisms:
1 shrinking the vessel wall.
2 blockage of small blood platelets.
3 Blood clotting.
Often all these factors work together and the exact role and importance of each of them differs in the pathogenesis of the porphyria.