Now a rare disease, acrodynia (painful extremities) primarily affects young children. The symptoms of irritability, photophobia, pink discoloration of the hands and feet, and polyneuritis can be attributed to chronic exposure to mercury. [1, 2, 3] Also see Mercury Toxicity.
The most frequent sources of mercury prior to the legislated removal of the heavy metal from these preparations were calomel-containing anthelminthics, laxatives, diaper rinses, teething powders, fungicides in paint, repeated gamma-globulin injections, termite-protected wood (mercury bichloride), watch batteries (ie, via ingestion), mercurial antibacterial ointments, mercurial skin-lightening creams, and dental amalgam. This legislation corresponded to the virtual disappearance of acrodynia. Present-day cases reveal more novel exposure, such as mercuric oxide used to treat eyelid mites. Some have suggested the disease may represent a delayed allergic or hypersensitivity reaction because not all persons exposed to mercurial compounds develop the disease.
Because the metal can be stored in the body to some extent and intolerance may develop long after exposure, morbid symptoms may appear weeks or months after the drug administration (ie, exposure), with its cause escaping recognition. The deleterious effects of relatively small doses of mercury on the nervous system that are sometimes seen in the course of acrodynia add to the acrodynic reaction. In acrodynia, no reflex dilatation of the peripheral vessels occurs in response to heat. Vasoconstriction is abolished only when the nerve supply to the arterioles is interrupted.
Acrodynia was once widely prevalent; however, it is rare today, owing to the discontinued use of mercury in different preparations.
Acrodynia was especially common in Australia. Epidemics of mercury poisoning have followed the release of mercury into the environment from industrial activity,  with uptake of methyl mercury from eating fish from Minamata Bay, Japan, and uptake of both inorganic and methyl mercury following the release of mercury vapor and its subsequent deposition in waterways from gold recovery procedures in the Amazon basin.  The ingestion of wheat and barley seed treated with an alkyl mercury fungicide for sowing, by a largely illiterate population in Iraq, led to a major outbreak of poisoning with a high fatality rate.
Acrodynia most often occurs in infants and young children. The age of onset is between 4 months and 8 years. Newborns and adults appear to be less susceptible to the disease.
Symptoms gradually disappear as insidiously as they began. Recovery is complete in the vast majority of patients. Older children tend to have less morbidity. Death can result in 10% of cases.