Definition

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

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.

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