Hypervitaminosis A is having too much vitamin A
in the body.
Vitamin A toxicity
There are two types of hypervitaminosis A:
- Abnormal softening of the skull bone (craniotabes -- in infants and children)
- Blurred vision
- Bone pain
- Bulging fontanelle
(the soft spot in an infant's skull)
- Changes in consciousness
- Decreased appetite
- Double vision (in young children)
- Hair changes, such as hair loss
and oily hair
- Increased pressure in the skull
- Liver damage
- Poor weight gain
(in infants and children)
- Skin changes, such as cracking at corners of the mouth, higher sensitivity to sunlight, oily skin, peeling, itching, and yellow color to the skin
- Vision changes
Exams and Tests
- Bone x-rays
- Blood calcium test
- Cholesterol test
- Liver function test
- Blood test to check vitamin A
Treatment involves simply stopping supplements (or rarely, foods) that contain vitamin A.
Most people fully recover.
- Excessively high calcium levels
- Failure to thrive
- Kidney damage due to high calcium
- Liver damage
Taking too much vitamin A during pregnancy may cause abnormal development in the growing baby. Talk to your health care provider about eating a proper diet while you are pregnant.
When to Contact a Medical Professional
Call your health care provider if you think that you or your child may have taken too much vitamin A, or you have symptoms of excess vitamin A.
To avoid hypervitaminosis A, avoid taking more than the recommended daily allowance of this vitamin. Recent emphasis on vitamin A and beta carotene
as anticancer vitamins may contribute to chronic hypervitaminosis A, if people take more than is recommended.
Mason JB. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 225.
Zile MH. Vitamin A deficiencies and excess. In: Kliegman RM, Stanton BF, St. Geme JW III, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 45.
Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.