Acute poisoning of infants with bulging fontanelle Acute poisoning may occur with a single dose of vitamin A exceeding 300,000 to 1 million IU in adults and 300,000 IU in children. Symptoms of elevated cranial pressure such as drowsiness or hyperexcitability, headache and vomiting appear 6 to 8 hours after ingestion and as soon as 1 to 2 days after ingestion. 12 to 20 hours later, skin redness and swelling appear, followed by peeling of the skin, which is most obvious on the palms of the hands, soles of the feet and other thick-skinned areas, and can return to normal only after a few weeks. In infants and young children, elevated cranial pressure is the main feature, and the fontanelle is bulging in infants with unclosed fontanelles. Chronic poisoning elevated transaminases Intake of vitamin A, 80,000 to 100,000 international units per day for six months in adults and 50,000 to 100,000 international units per day for more than six months in infants and children can cause chronic poisoning. When vitamin A poisoning occurs, people first experience loss of appetite and weight loss, followed by dry skin, flaking, cracking, dry hair and hair loss, red and swollen gums, dry and cracked lips, nose bleeding and other symptoms of skin and mucous membrane damage. There are also painful muscle swelling, enlarged liver and spleen, and elevated transaminases. Vitamin A and foods containing vitamin A should be discontinued as soon as symptoms of vitamin A excess appear. Symptoms usually disappear within 1 to 2 weeks, and skeletal changes can take about 2 to 3 months to recover. No special treatment is usually required. Carotenoid yellow skin When carotenoid-rich food is consumed in excess, a large amount of carotenoid cannot be converted into vitamin A in the small intestine mucous membrane cells sufficiently quickly, and the level of carotenoid in the blood increases to 4.7 micromolar to 9.3 micromolar/liter (normal is 1.9 micromolar to 2.7 micromolar/liter) per liter of blood, carotenemia can occur, and the yellow pigment is deposited in the skin and subcutaneous tissues. The yellow pigmentation in the skin and subcutaneous tissues is obvious in the tip of the nose, nasolabial crease, forehead, palms and soles of the feet. Although the absorption of large amounts of carotene can cause yellow skin staining, it does not cause vitamin A toxicity. Because the absorption rate of carotene is only 1/3, only 1/2 of the absorbed carotene is converted into vitamin A. Therefore, only 1/6 of the intake is converted into vitamin A, so it will not be poisoned. After the occurrence of carotenemia, as long as you stop eating a large amount of carotenoid-rich food, carotenemia can gradually disappear within 2 to 6 weeks, and generally no special treatment is needed. Therefore, if a child is not suffering from vitamin A deficiency, it is not advisable to give him/her vitamin A preparations, especially if they are taken for a long time. Adults, on the other hand, are prone to fractures if they take too much vitamin A. If they are not deficient, they should not take them either.