selenosis

Selenosis, also known as selenium toxicity, is a medical condition resulting from excessive intake of selenium, whether from diet, supplements, or environmental and occupational exposure. It can be acute after a single high-dose exposure or chronic from long-term consumption of foods or supplements with high selenium content.

Causes and sources: Seleniferous soils and groundwater in certain regions can lead to high selenium levels in crops and water. Dietary supplements and fortified foods containing selenomethionine or selenite can contribute, especially when taken in excess of recommended daily allowances. Occupational exposure occurs in industries such as metal refining, electronics, and glass production. Ingesting contaminated food or water is a common route in endemic areas.

Clinical features: Acute selenosis presents with gastrointestinal symptoms (nausea, vomiting, abdominal pain, diarrhea), garlicky breath, fatigue, dizziness, and irritation. Chronic selenosis features include hair loss (alopecia), brittle nails (onychodystrophy), dermatitis, a metallic or garlic odor, fatigue, irritability, and sometimes peripheral neuropathy. Severe toxicity can affect the liver and kidneys and may cause confusion or hypotension in extreme exposures.

Diagnosis: based on history of selenium exposure and laboratory confirmation with elevated selenium levels in blood, urine, hair, or nails. Measurement of plasma or whole-blood selenium and related biomarkers can aid assessment.

Treatment and prognosis: immediate cessation of exposure is essential. Supportive care for symptoms; there is no universally approved antidote. In severe cases, hospital management is required. With removal of excess selenium, symptoms may improve over weeks to months, though some hair and nail changes can persist longer.

Prevention: avoid unnecessary selenium supplementation, regulate dietary sources, monitor occupational exposure, and consider regional soil and water selenium levels.