Diffuse Palmoplantar Keratotic Papules and Melanosis

Diffuse palmoplantar keratotic papules and melanosis Globally, millions of people are exposed to arsenic from drinking contaminated water, but arsenic exposure can also occur in many other ways. Chronic arsenic intoxication has been described in patients with a history of environmental, occupational, and medicinal exposure to arsenic. Here, we present a case of a patient treated with Mongolian medicine for epilepsy for 3 years, with development of marked hyperpigmentation, guttate hypopigmentation, and keratotic papules. A 9-year-old boy presented with punctate papules over the palmoplantar palms and soles for 10 months and darkening of his whole body for 8 months. Six years ago, he took lamotrigine for the treatment of epilepsy but discontinued because of stomachache. He began to take traditional Chinese Mongolian medicine, realgar (prominent arsenic sulfide), for epilepsy 3 years ago. Ten months ago, the patient developed disseminated keratotic papules appearing on the palms and soles. He was admitted to a local doctor and empirical treatment with oral retinoids was started, but more keratotic papules appeared on his hands and feet in the following months, and hyperpigmentation spread to all parts of his body. The patient also suffered from mouth ulcer and mild pruritus but had no headache, weakness, or other systemic symptoms. He has no history of allergies and lives in Inner Mongolia of China. All family members are in good health with no family history of any skin conditions or similar symptoms. Examination was significant for keratotic papules with hypopigmentation on the palms and plantar soles (Fig. 1a,b) and guttate hypopigmentation superimposed on beige hyperpigmentation throughout the body, similar to “raindrops on a dusty road” (Fig. 1c). Laboratory examination: blood routine examination showed a mild anemia (RBC 3.25 9 10/l [reference value 4.00–5.50 9 10/l], HGB 113 g/l [reference value 120–160 g/l]).