Vitamin A toxicity typically causes headache and increased intracranial pressure. Chronic vitamin A toxicity causes alterations in the skin, hair and nails, liver problems, and, in a foetus, birth defects.
Severe vitamin A toxicity in children might result from taking high doses, typically unintentionally. In children, toxicity may cause pruritus, anorexia and failure to grow up properly. Toddlers who are given excessive doses of vitamin A might develop toxicity within a couple of weeks.
Despite the fact that carotene is converted to vitamin A within the body, excessive intake of carotene causes carotenemia, not vitamin A toxicity. Carotenemia is usually asymptomatic, but might lead to carotenosis, wherein the skin becomes yellow, particularly on the palms and soles.
When taken as a nutritional supplement, carotene continues to be linked with increased cancer risk; however, the hazard does not appear to rise when carotenoids are consumed in the form of vegetables and fruits.
Megavitamin therapy is just a possible cause, as are substantial daily doses of vitamin A or its metabolites that are occasionally given for nodular acne or other skin problems. Adults who consume more than necessary of vitamin A may develop osteoporosis.
Despite the fact that symptoms might vary, headaches and rash typically develop during severe or chronic toxicity. Acute toxicity causes increased intracranial pressure. Early signs of chronic toxicity are sparsely dispersed, coarse hair, alopecia of the brows, dry, rough skin, dry eyes and chapped lips.
Cortical hyperostosis of bone and arthralgia might occur, particularly in children. Fractures might occur easily, particularly in older people. In vitamin A toxicity, fasting serum retinol levels may increase to abnormal levels.
Differentiating vitamin A toxicity from other problems can be difficult. Carotenosis can also happen in severe hypothyroidism and anorexia nervosa, perhaps since carotene is transformed to vitamin A more slowly. Complete restoration often happens if vitamin A ingestion stops. Signs and symptoms of long-term toxicity typically disappear within one to four weeks.