查了这些可能的情况，都不象。蛔虫也不象。

除重金属外，似乎下面的都不对症

Blue/purple patches may be haemangiomas (will blanch with pressure), Kaposi's sarcoma (will not blanch) or purpura/ecchymoses (non-blanching, usually smaller lesions). Other rarer causes include heavy-metal toxicity or Peutz-Jeghers syndrome.

venous lake 也不象。