Chronic arsenic toxicity can be manifested by arsenical melanosis, punctate plantar and palmar keratoses, and Bowen's disease (squamous carcinoma in situ).
There would also appear to be an increased risk of internal neoplasia. In patients with Bowen's disease alone, the risk of internal neoplasia is apparently increased if the Bowen's disease is on non-sun exposed skin.
- Skin cancers and precancers should be treated in standard ways.
- The role of long term oral or topical retinoids in preventing skin and other cancers has not been established.