Vitamin a deficiency

Vitamin A deficiency is a nutritional disorder in which too little vitamin A, from poor intake or poor absorption, impairs vision, immune defences and epithelial tissues. It is widespread across over half the world's countries, hitting young children and pregnant women hardest in low-income settings, but is rarely seen in wealthy ones. Common causes are malnutrition, recurrent diarrhoea and measles, while malabsorption from bowel, liver or pancreatic disease, bariatric surgery and prematurity add risk. Night blindness often appears first; dry conjunctivae, Bitot spots and corneal ulceration can follow and lead to blindness; infections also become more serious in children. Diagnosis rests on history, eye and skin examination and a serum retinol blood test, which is least reliable for mild deficiency. Treatment is vitamin A supplementation by mouth, which lowers childhood illness in deficient populations; the condition is treatable and preventable.

Seek urgent care for unusual bleeding or bruising, breathlessness at rest, or a swollen painful leg. See a doctor for persistent tiredness, pale skin, or any symptom of anaemia in a man or a woman after the menopause, which always needs a cause to be found. Call the local emergency number for any symptom that is sudden and severe. This page is a reference for healthcare professionals and does not replace an assessment.