Hypervitaminosis A

Vitamin A excess can present as two forms: 

  • Vitamin A toxicity and 
  • Carotenaemia.


Hypervitaminosis A results from overconsumption of non-prescription nutritional supplements, prescription medications containing vitamin A derivatives and foods high in vitamin A.


Carotenaemia is a benign disorder caused by excessive ẞ-carotene intake. In carotenaemia, carotenes are excreted from sebaceous glands and sweat glands, and ultimately deposit in the stratum corneum. This results in carotenoderma. 

Acute vitamin A toxicity manifests with headaches, vision changes, fatigue, anorexia, nausea, vomiting, myalgias and arthralgias. Weight loss can be observed with chronic intoxication. Individuals with chronic hypervitaminosis A have dry and scaly skin, desquamation, cheilitis, alopecia, follicular hyperkeratosis and hyperpigmentation, associated pseudotumor cerebri and skeletal changes (premature closure the epiphyses and pathological bone fractures).


Prognosis:

Vitamin A toxicity: discontinuation of vitamin A leads to resolution of almost all symptoms of vitamin A toxicity, with the exception of cirrhosis and sequelae related to pseudotumour cerebri.


Carotenaemia: Excellent prognosis with no clear long-term adverse effects. Pigmentary changes resolve within weeks to months of decreasing B- carotene intake.

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