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Hypervitaminosis A

Definition

Hypervitaminosis A is having too much vitamin A in the body.

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Alternative Names

Vitamin A toxicity

Causes, incidence, and risk factors

There are two types of vitamin A hypervitaminosis:

Acute -- caused by taking too much vitamin A over a short period of time
Chronic -- occurs when too much of the vitamin is present over a longer period

Chronic vitamin A toxicity develops after taking too much vitamin A for long periods.

Symptoms

Abnormal softening of the skull bone (craniotabes -- infants and children)
Blurred vision
Bone pain or swelling
Bulging fontanelle (infants)
Changes in consciousness
Decreased appetite
Dizziness
Double vision (young children)
Drowsiness
Headache
Increased intracranial pressure
Irritability
Liver damage
Nausea
Poor weight gain (infants and children)
Skin and hair changes
- Cracking at corners of the mouth
- Hair loss
- Higher sensitivity to sunlight
- Oily skin and hair (seborrhea)
- Skin peeling, itching
- Yellow discoloration of the skin
Vision changes
Vomiting

Signs and tests

Bone x-rays
Blood calcium test
Cholesterol test
Liver function test
Blood test to check vitamin A levels

Treatment

Treatment involves simply stopping the use of too much vitamin A.

Expectations (prognosis)

Most people fully recover.

Complications

Excessively high calcium levels
Failure to thrive in infants
Kidney damage due to high calcium
Liver damage

Taking too much vitamin A during pregnancy may cause abnormal development in the developing baby. Talk to your health care provider about eating a proper diet while you are pregnant.

Calling your health care provider

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.

Prevention

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.

References

Mason JB. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 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: Saunders Elsevier; 2011:chap 45.

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