What is the difference between chilblains and erythromelalgia ? no rash but everynight the feet get red, little swollen painful itchy and hot .

Huge difference: Chilblains is usually the feet, itchy, comes from cold-wet exposure. Erythromelalgia is very red, very hot & red, stimulated by heat, often by hot sun, often 1 leg, the entire leg. Erythromelalgia is much more common among those taking a calcium channel blocker and tends to respond dramatically to a single dose of aspirin. Amlodipine and nifedipine are common CCB.