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Chronic arsenic poisoning

Author: Vanessa Ngan, Staff Writer, 2005.

Chronic arsenic poisoning — codes and concepts

What causes 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 three main sources of exposure are occupational exposure, natural contaminants 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 used to produce some semiconductor computer chips). It has been found in stimulants used by sportsmen and in compounded medications such as the patent medicine, Fowler's tonic. 

The absorption and distribution of arsenic

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.

What are the signs and symptoms of chronic arsenic poisoning?

Signs and symptoms of chronic arsenic poisoning may not occur until 2 to 8 weeks after exposure.

Skin features of chronic arsenic poisoning

Typical findings include:

Affected organFeatures
  • Excessive darkening of the skin (hyperpigmentation) in areas that are not exposed to sunlight
  • Excessive formation of scaly skin on the palms and soles (arsenical keratosis)
  • Exfoliative dermatitis
  • Arsenic-induced skin cancers (especially Bowen disease)
  • Transverse white bands of arsenic deposits across the bed of the fingernails (Mee's lines)
  • Arsenic deposits in hair
Nervous system
  • Sensory changes, numbness and tingling in a “stocking-glove” distribution (sensory peripheral neuropathy)
  • A headache, drowsiness, confusion
  • The distal weakness of small muscles of the. hands and feet
Blood and urine
  • Haemolytic anaemia (moderate)
  • leukopenia (low white cell count)
  • Proteinuria (protein in the urine)
  • Inflammation of respiratory mucosa
  • Peripheral vascular insufficiency
  • Increased risk of cancer of lung, liver, bladder, kidney and colon

What is the treatment of chronic arsenic poisoning?

There is no specific treatment for chronic arsenic poisoning. Once it has been identified further exposure should be avoided.

What is the outcome of chronic arsenic poisoning?

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.

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Related information



  • 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:

On DermNet NZ

Other websites

  • 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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