There are many causes for the bruised purple appearance of the pachyderm, such as trauma, frostbite, purpura, and abnormal blood clotting. 1. Trauma: localized extrusion by external forces can cause local subcutaneous capillary rupture, which may lead to the appearance of bruises at the level of the piazza. 2. Frostbite: The low temperature of the external environment will cause poor local circulation, which may also cause the appearance of purpura. 3. Purpura: rupture of subcutaneous capillaries may cause bleeding spots on the skin, skin bruises, and may also cause rupture of subcutaneous capillaries in the pachyderm leading to pachyderm bruising. 4. Abnormal coagulation function: abnormal coagulation function caused by various reasons, may cause subcutaneous capillary rupture of the pachyderm, which may also lead to pachyderm bruises. There may be other causes of pachymetry, so it is recommended that you go to the hospital for examination to determine the cause of the problem and follow the doctor’s instructions for treatment.