My otherwise healthy adult daughter has just been diagnosed with primary, idiopathic erythromelalgia based on extensive blood work ruling out other diseases. Her feet become hot and red when wearing socks and closed shoes for exercise and sometimes when her feet "dangle" for an extended period of time. She does not experience any pain. Her dermatologist has told her the cases she has seen have always had pain. Is there any way of knowing when pain commences--months, years, how long? Is it possible that this will just manifest with heat and redness? Will continuing to exercise and being in a hot environment cause the flares that are now pain free to speed up the onset of pain?