The differential diagnosis of erythermalgia is sometimes complicated b
y the absence of consensus on proposed diagnostic criteria. Unwarrante
d diagnosis can result From any clinical situation leading to burning
sensations in the limbs. This can occurs in patients with peripheral n
europathies who often experience dysesthesia when going to bed when th
e legs are under the covers; in such cases, redness and local warmness
are missing. Venous insufficiency can also produce sensations of warm
feet, often at retiring, together with edema and an increase in local
heat. Algodystrophy, during the inflammatory phase can also mimic ery
thermalgia with intense pain and local modifications. Nevertheless. th
e unilateral aspect and persistence of the symptoms together with the
post-traumatic situation usually directs the diagnosis. Acrodynia is a
rare disease caused by excessive mercury intake and should be discuss
ed in children. Vasomotor impairment in the limbs is the main sign. Th
e red color of the hands and feet is accompanied by intense paroxysmal
burn-type pain. The diagnosis is confirmed by high mercury levels in
urine. Fabry's disease is a hereditary sphingolipidosis transmitted on
chromosome X rind occurs predominantly in men, often starting early i
n childhood with burning sensation in the limbs. The diagnosis should
be entertained in children with pseudoerythermalgia and is confirmed b
y chromatographic search for abnormal sphingolipids in the urine (J Ma
l Vasc 1996: 21: pages 84-87).