Environmental Medicine Update

by Marianne Marchese, ND

What’s Causing Those Skin Lesions?

The Arsenic Connection

Introduction

Changes in the skin are often the hardest conditions to diagnose. Dermatitis is a general term for inflammation of the skin that may include conditions such as atopic dermatitis (eczema), seborrheic dermatitis, contact dermatitis, or what a patient may simply refer to as a rash. There are many causes and triggers for dermatitis. One cause that is often overlooked is the heavy metal arsenic.

Arsenic Overview

Most people in the US are exposed daily to low levels of arsenic, often without their knowledge. Common sources of exposure are food, water, and air. Arsenic is a hazardous, naturally occurring element in the earth. It is present in two forms, organic and inorganic. In the environment, arsenic is combined with oxygen, chlorine, and sulfur to form inorganic arsenic compounds. Arsenic in animals and plants combines with carbon and hydrogen to form organic arsenic compounds. Organic arsenic is deemed less toxic because it is rapidly cleared from the body. Inorganic arsenic is considered more toxic and is classified as a carcinogen. Arsenic can be found in small amounts in the atmosphere, groundwater, and surface water. Arsenic is an ingredient in a wide variety of products in manufacturing industries, such as wood preservatives, herbicides, insecticides, pesticides, and semiconductors. It is also found in food and water.¹

Diet is a large source of both inorganic and organic arsenic for typical individuals. Organic arsenic from food is considered less toxic, but it really depends on the individual. Organic arsenic can be found in fish such as shrimp and crab.² Another dietary source of arsenic is chicken. Arsenic is an approved feed supplement that farmers use to control intestinal parasites in chickens. Current data suggest that 65% of the arsenic in poultry is inorganic.³ A person consuming about 2 ounces of chicken per day may be getting 3.52 to 5.24 μg of inorganic arsenic daily. This is below the World Health Organization’s safe level for dietary arsenic consumption but may still pose health risks.³

Food is not the only source of daily exposure. Drinking water is the most common source of inorganic arsenic. Numerous studies have shown the health effects associated with arsenic in drinking water both within and outside the US. It is through these studies that ingestion of arsenic from drinking water has been definitively linked to increased incidence of cancer and a number of noncancerous effects, including skin lesions.² In January 2001, the EPA issued new public drinking water standards for arsenic: 10 parts per billion (ppb). These levels reflect inorganic arsenic.

Inorganic arsenic compounds are mainly used to preserve wood. Copper chromated arsenic (CCA) is used to make “pressure-treated” lumber. CCA is no longer used in the US for residential uses; it is still used in industrial applications. CCA wood was used in backyard decks and large wooden playground structures and is a common source of arsenic exposure. In 2002, the EPA announced that CCA-treated wood would be withdrawn from the residential marketplace by the end of 2003.⁴

Another source of arsenic exposure is food grown in contaminated soil. Arsenic can also accumulate in food from the use of fertilizers and pesticides.⁵ Cotton was the main crop sprayed with pesticides containing arsenic. These pesticides were also used on residential lawns and parks. In 2009 the EPA phased out arsenic-containing pesticides, but they were still in use on golf courses until this year.⁶

Signs of Arsenic Exposure

Inorganic arsenic exposure is highly toxic and carcinogenic in both high-dose and low-dose levels of exposure. Low-dose daily levels of exposure can cause subtle changes to one’s health, making it difficult to find the link to arsenic exposure and health conditions. Arsenic enters the human body by dermal contact, inhalation, or food consumption. The tissues most often affected by arsenic exposure are the skin, nasal passages, lungs, gastrointestinal tract, and liver. Exposure to chronic low-dose arsenic is associated with an increased risk of epithelial cancers of the skin such as Bowen’s disease, squamous cell carcinomas (SCC), and basal cell carcinomas (BCC).⁷

Early signs of arsenic exposure affecting the skin include keratosis, thickening and scaling of the skin, and hyperpigmentation. Signs and symptoms of chronic arsenic poisoning may not occur until 2 to 8 weeks after exposure. The hyperpigmentation is marked by small discolored spots, diffuse dark brown spots, or darkening of the skin on the limbs and trunk. This is called melanosis. Keratosis usually appears as bilateral thickening of the palms and soles; however, multiple raised keratotic lesions may appear on palms and soles.⁸

The prevalence of skin manifestations in children due to drinking arsenic-contaminated water is widely reported from epidemiological studies.⁸ What is interesting is that if arsenic levels in drinking water were reduced, the skin lesions improved. In a study that followed up on persons who had arsenic-induced skin lesions, it showed that arsenic remediation activities and safe water programs successfully reduced arsenic exposure in the drinking water and thus improved the lesions.⁹ A decrease in drinking-water arsenic over time was associated with increased probability that skin lesions would improve within a period of 10 years.

The early stages of the dermal effects of arsenic exposure can mimic several other conditions that also cause skin color changes, thickening, and scaling. There are many dermatological mimickers that can produce either darkening or keratoses and at times make it difficult to diagnose. Some differentials include pityriasis versicolor, freckles, lentigines, photopigmentation, lichen planus pigmentosus, Addison’s disease, hemochromatosis, drug-induced, corn/calluses, seborrheic keratosis, psoriasis, hyperkeratotic eczema, tinea pedis, and many others. Some of these other conditions are quite common, and arsenic is often not considered as a cause for skin lesions until later.¹⁰

Lab tests are important for diagnosis in where arsenicosis-simulating skin lesions pose a diagnostic challenge. Arsenic may be elevated in the blood, urine, hair, and nails of persons affected. Also, it is important to test the home or office drinking water for elevated levels of arsenic, since it is the most common source of exposure.

Summary

Chronic arsenic exposure is primarily diagnosed based on changes in the skin, but the manifestations can, at times, be confused with other dermatoses. Arsenic as a cause of skin lesions is often an afterthought. A high index of suspicion, especially in those people from a region with arsenic contamination in groundwater, is required. Other sources of arsenic exposure, such as diet, should also be investigated as removing the source of exposure may help improve skin lesions due to arsenic.

Dr. Marchese is the author of 8 Weeks to Women’s Wellness: The Detoxification Plan for Breast Cancer, Endometriosis, Infertility, and other Women’s Health Conditions. Dr. Marchese graduated from the National College of Naturopathic Medicine in 2002. She maintains a private practice in Phoenix, Arizona, and teaches gynecology at Southwest College of Naturopathic Medicine.

Notes

1. Dastgiri C et al. arsenic exposure, dermatological lesions, hypertension, and chromosomal abnormalities among people in a rural community of northwest Iran. J Health Popul Nutr. 2010 February;28(1):14–22.

2. Hughes MF et al. Arsenic exposure and toxicology: a historical perspective.

Toxicol Sci. 2011 October;123(2):305–332.

3. Taylor DA. Funky chicken: consumers exposed to arsenic in chicken. Environ Health Perspect. 2004 January;112(1):A50–A51.

4. Pike-Paris A. Arsenic in a child’s world. Pediatr Nurs. 2004 May-Jun;30(3):215–218.

5. Isokpehi RD. Knowledge building insights on biomarkers of arsenic toxicity to keratinocytes and melanocytes. Biomark Insights. 2012;7:127–141

6. Organic arsenicals [Web page]. Environmental Protection Agency. http://www.epa.gov/oppsrrd1/reregistration/organic_arsenicals_fs.html.

7. Isokpehi RD et al. Knowledge building insights on biomarkers of arsenic toxicity to keratinocytes and melanocytes. Biomark Insights. 2012;7:127–141.

8. Majumdar KK. Effect of drinking arsenic-contaminated water in children. Indian J Public Health. 2012 Jul-Sep;56(3):223–226

9. Seow WJ et al. Arsenic reduction in drinking water and improvement in skin lesions: a follow-up study in Bangladesh. Environ Health Perspect. 2012 Dec;120(12):1733–1738.

10. Das NK, Sengupta SR. Arsenicosis: Diagnosis and treatment. Indian J Dermatol Venereol Leprol. 2008;74:571–581.