Acrodynia is a condition that primarily affects young children and is characterized by pink discoloration of the hands and feet, irritability, photophobia (sensitivity to light) and polyneuritis (inflamed nerves). The symptoms are often caused by chronic mercury exposure.
Acrodynia was common in the past when the use of mercury-containing preparations was common. It is rarely seen now.
The most common cause today is exposure in young children due to the ingestion of mercury from a broken thermometer.
Mercury spills are difficult to clean up and can remain undetected in a carpet for some time where the crawling children are more likely to inhale or ingest the heavy metal.
Dental amalgam used for fillings is also suspected of being a possible source of mercury toxicity from chronic exposure. It has been linked to systemic diseases or chronic illnesses but to date, there is lack of scientific evidence supporting this. In any case, new materials to replace mercury for dental amalgam are being developed.
Commonly used mercury in the past were calomel-containing anthelmintics, laxatives, diaper rinses, teething powders, termite-protected wood, watch batteries, mercurial antibacterial ointments, dental amalgam, etc.
However, not all persons developing acrodynia have been exposed to mercury.
A delayed allergic or hypersensitivity reaction has been suggested as a cause in such cases.
Moreover, the symptoms can develop after a long duration [weeks or months after the exposure, thus escaping the correlation.
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.
The age of onset is between 4 months and 8 years.
Acrodynia is known by various other names
- Pink disease
- Erythredema polyneuropathy
- Bilderbeck’s diease
- Selter’s Disease
- Swift-Feer disease.
The symptoms and signs of mercury toxicity may not appear until weeks or months after exposure has occurred.
The initial signs are drowsiness, lack of energy [listless], irritability and a tendency to cry. Parents would note a loss of appetite and weight loss as well. Half of the patients have a sensitivity to light [photophobia]. There is generalized weakness and pain in the extremities. There is a complaint of hypotonia and the ability to hyperextend limbs.
Muscle atrophy may be present. The child may refuse to walk.
After 2-4 weeks of these initial symptoms, the following characteristic changes are noted:
- Tip of the nose, fingers, and toes turn pinkish. The pink color darkens progressively and then develops into net-like pattern [resticulate erythema]
- Painful, cold, cyanotic (blue), erythematous (red) and swollen hands and feet. Erythema is usually blotchy but may be diffuse.
- Blotchy, macular or papular erythema on trunk
- Hemorrhagic puncta are also noted
- Lichenified excoriation [thickened rough skin] due to extreme pain and itchiness in extremity.
- Salaam position – The patients sit with their heads between their legs and rub their hands together.
- Hyperhidrosis (excessive sweating) with a mouse-like smell
- Miliaria and secondary bacterial skin infections.
- Inflammation, swelling, and erosion of the gum followed by loss of teeth.
- Persistently raised blood pressure
- Precipitation of urine
- Upper Respiratory Infection
- Baldness [Alopecia] and nail loss
In the long term, some patients may have lower intelligence test scores and abnormal EEG findings.
- Toxicities to copper, arsenic, gold, or thallium
- Kawasaki disease [skin manifestations]
- Acanthosis Nigricans
- Raised mercury levels in urine as seen in a 24-hour urine collection sample.
- <10mcg are considered within range.
- >300 mcg/L are considered toxic [symptoms also occur around this level]
- Increased amounts of vanillylmandelic and homovanillic acid in urine.
- Due to blockage of the action of catechol methyl transferase
- Increase in the excretion of 17-ketosteroid
Treatment of Acrodynia
- Removal of the inciting agent if present
- Supportive treatment
- Fluid and electrolyte correction
- Vitamin-rich intake to correct the deficiency
- The chelating agent – meso 2,3-dimercaptosuccinic acid
- Competes and prevents methylmercury uptake by erythrocytes and hepatocytes.
- Hemodialysis in acute renal failure
- L-cysteine as a chelating agent may be added
- Peritoneal dialysis and plasma exchange
- Tolazoline for sympathetic overactivity.
- Antibiotics for the prevention of secondary bacterial infections in massive hyperhidrosis
Often the recovery is complete. Death occurs in 10% of cases.
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