Arsenical Keratosis Clinical Presentation

Updated: Apr 02, 2018
  • Author: Chih-Shan Jason Chen, MD, PhD; Chief Editor: Dirk M Elston, MD  more...
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Presentation

History

Arsenical keratoses, skin hyperpigmentation, and several types of skin cancers, including basal cell carcinoma, squamous cell carcinoma, and Merkel cell carcinoma, [31] are skin lesions characteristic of long-term arsenic exposure. A long latency period (years to decades) occurs before the development of these cutaneous lesions. A study in West Bengal, India, has shown an average latency for skin lesions was 23 years from first exposure to arsenic. [26, 11] Chronic arsenic exposure usually does not cause symptoms, and the skin lesions are usually the first sign to manifest clinically.

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Physical Examination

Arsenical keratoses are usually multiple and typically occur at sites of friction and trauma, especially on the palms and the soles. Keratoses usually manifest as small, punctate, nontender, horny, hard, yellowish, often symmetric, corn-like papules. The diameter of the papule ranges from 0.2-1 cm.

A mild form of the arsenic keratoses may manifest as diffuse thickening or small (5 mm) verrucous papules or plaques. These lesions are most frequently seen on the thenar and lateral borders of the palms; the base and lateral aspect of the digits; the soles, heels, and toes of the feet, as demonstrated in the image below. Keratoses may also develop on the dorsum of the hands, the arms, and the legs.

Arsenical keratosis on the sole of a carpenter. Arsenical keratosis on the sole of a carpenter.

Another type of arsenical keratosis seen in most patients with arsenical cancers manifests as scaly erythematous or pigmented patches on unexposed body areas.

Mee lines (transverse white bands) on the fingernails are seen in acute and chronic arsenic toxicity.

Other skin manifestations of chronic arsenic toxicity include hyperpigmented and hypopigmented macules on the torso and limbs. The pigmented lesions often present as finely freckled or raindroplike macules distributed bilaterally symmetrically. Diffuse hyperpigmented patches in the intertriginous, genital, and acral areas may be an early sign of chronic arsenic toxicity.

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Complications

Arsenical keratosis occasionally evolves into carcinoma after a number of years. Bowen disease is the most common form of skin cancer induced by arsenic exposure. Arsenical squamous cell carcinoma occurs less frequently than Bowen disease, but it appears to be more aggressive than sun-induced squamous cell carcinoma. Previous reports have shown a much higher incidence of fatal metastases among patients with arsenical squamous cell carcinoma. Basal cell carcinoma is also associated with chronic arsenicalism. Skin cancers may develop in areas not exposed to sun light.

A variety of internal cancers due to arsenic ingestion have been reported. The presence of arsenic-induced cutaneous Bowen disease has been viewed as a cutaneous marker of possible internal malignancy, but this issue is still controversial.

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