Summary Statement : A disease of infants and young children that is an allergic reaction to mercury......

Details : A disease of infants and young children that is an allergic reaction to mercury, is characterized by dusky pink discoloration of hands and feet with local swelling and intense itching, and is accompanied by insomnia, irritability, and sensitivity to light.

Merriam-Webster's Medical Desk Dictionary, 3rd Edition

© 2006 Merriam-Webster, Inc.

Background: 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.
Pathophysiology: 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.
Frequency:
· In the US: Acrodynia was once widely prevalent; however, it is rare today, owing to the discontinued use of mercury in different preparations.
· Internationally: 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.
Mortality/Morbidity: Older children tend to have less morbidity. Death can result in 10% of cases.
Age: 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.

· Children initially become listless, drowsy, and irritable, with a tendency to cry.
· Anorexia and subsequent weight loss can occur.
· More than 50% of patients demonstrate photophobia.
· Hypotonia, the ability to hyperextend or overextend the limbs, and atrophy of muscles are noted. The child may refuse to walk.
Physical:
· The initial symptoms are followed by the numerous cutaneous manifestations in 2-4 weeks. The skin changes are characteristic. The review by Dinehart et al from 1988 is notable.
· Early in the course of the disease, the tip of the nose, fingers, and toes acquire a pinkish color, which subsequently develops into a reticulate erythema of deeper hue.
· The hands and feet become painful, cold, cyanotic, erythematous, and swollen. Erythema is usually blotchy but may be diffuse. Hemorrhagic puncta are also noted. On the trunk, the erythema is blotchy and may be macular or papular.
· Extreme pain and pruritus in the extremity often leads to lichenified, excoriated changes as the child constantly rubs and scratches his or her skin.
· Patients may assume the "salaam position" in which they sit with their heads between their legs and rub their hands together.
· Inflammation, swelling, and focal gum erosion can been seen with subsequent loss of teeth. These changes are early.
· A notable symptom is massive hyperhidrosis with a mouselike smell, which may lead rapidly to miliaria rubra. This can easily turn to bacterial secondary infection with a tendency for ulcerating pyoderma.
· Persistent hypertension, tachycardia, susceptibility to bronchitis, dyspepsia, precipitant micturition, salivation, and hypotonia can be observed. Usually, the patient develops a moderate upper respiratory tract infection with a sore throat.
· Alopecia has also been noted.
· Nail loss has been reported.
Causes:
· Mercury exposure in a sensitive person is considered to be responsible for the development of acrodynia. A genetic predisposition is possible.