Hypervitaminosis A

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Vitamin A source

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
• Fatigue
• Headache
• Impotence and ejaculation failure
• Increased intracranial pressure
• Irritability
• Nausea
• Osteoporosis
• 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
• Swelling of breast tissue in men (gynecomastia)
• Vision changes
• Vomiting

Signs and tests

• Bone hardening (calcification)
• High blood calcium levels
• High cholesterol
• High serum creatinine (suggesting kidney damage)
• Serum 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
• Kidney damage due to high calcium
• Liver damage
• Osteoporosis
• Prostate cancer

Recent studies show that taking too much vitamin A during pregnancy can cause abnormal development in the fetus. 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

Zile M. Vitamin A deficiencies and excess. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF. Nelson Textbook of Pediatrics. 18th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 45.

Review Date: 6/17/2008

Reviewed by: Elizabeth H. Holt, MD, PhD, Assistant Professor of Medicine, Section of Endocrinology and Metabolism, Yale University. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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