Chronic arsenic poisoning
Chronic arsenic poisoning is due to repeated or continuous exposure to arsenic compounds, which leads to an accumulation of arsenic in the body. The 3 main sources of exposure are occupational exposure, natural contaminant of drinking water (from some deep water wells), and ancient Chinese medicinal remedies containing arsenic.
Occupational exposure is mainly from the smelting industry, in which arsenic is a by-product of ores containing lead, gold, zinc, copper, cobalt and nickel. It is also used in glass manufacturing and the microelectronics industry (where gallium arsenide is use to produce some semiconductor computer chips).
Absorption and distribution
There are several forms of arsenic. Pentavalent arsenic is well absorbed through the gut but less toxic than the trivalent form which is more lipid soluble and absorbed through the skin. The most toxic form is arsine gas, which is inhaled.
Arsenic compounds are well absorbed within 24 hours and redistributed to the liver, lungs, intestinal wall and spleen, where they bind to the sulfhydryl groups of tissue proteins. Arsenic also replaces phosphorus in the bone where it may remain for years. Hence, the effects of chronic poisoning can still be seen years after exposure has stopped.
Signs and symptoms of chronic arsenic poisoning
Signs and symptoms of chronic arsenic poisoning may not occur until 2 to 8 weeks after exposure.
Hyperpigmentation and raindrop hypopigmentation
Typical findings include:
|Blood and urine||
Treatment of chronic arsenic poisoning
There is no specific treatment for chronic arsenic poisoning. Once it has been identified further exposure should be avoided. Recovery from the signs and symptoms may take weeks to months from when exposure is stopped. In particular, effects on the nervous system may take months to resolve and in some cases a complete recovery is never achieved.
- Book: Textbook of Dermatology. Ed Rook A, Wilkinson DS, Ebling FJB, Champion RH, Burton JL. Fourth edition. Blackwell Scientific Publications.
- Arsenical Keratosis – Medscape Reference
- Sengupta SR, Das NK, Datta PK. Pathogenesis, clinical features and pathology of chronic arsenicosis. Indian J Dermatol Venereol Leprol [serial online] 2008 [cited 2009 Jan 26];74:559-70. Available from: http://www.ijdvl.com/text.asp?2008/74/6/559/45097
On DermNet NZ:
- Arsenic – World Health Organization (WHO)
- Heavy Metal Toxicity – Life Extension
- Heavy Metal Handbook: A Guide for Healthcare Practitioners. Science Subcommittee of the Heavy Metals Remediation Committee of the Vashon-Maury Island Community Island Community Council, 2003.
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