A blood test which maps your genes specifically looking for Fabry Disease. If you are related to anyone who has been diagnosed or have experienced erythromelalgia disease (burning/redness in the hands, feet or head/ears), get checked immediately because damage to your nerves may be occurring which is irreversible.
Also get checked if you don't sweat enough (hypohidrosis) or have reduced organ function (especially kidney failure) or corneal whirling (looks like a cloud in your eye).