The first is less severe, characterised by blanching spasms of blood vessels leading to the hands and feet, initiated by cold, moisture, even emotional stress and low blood sugar. Sort of a finger migraine. After the spasm relaxes, the tissue distal becomes red, hot, even painful. R. Disease is more serious and perhaps deriving from different causes as well. The spasms may not subside, the effected tissues can become purplish, and in extreme cases, gangrenous.