What are the clinical signs of vitamin A poisoning?
The signs of vitamin A poisoning can be sudden or delayed in onset. When very large doses of vitamin A are ingested, dogs may develop rapid signs of vomiting, drowsiness, irritability, and peeling of the skin.
More commonly, oversupplementation of vitamin A for weeks to months can eventually result in a poor hair coat, rough or dry skin, weakness, weight loss, constipation, excessive bone development, and painful or limited movement. Excessive vitamin A intake during pregnancy has been associated with cleft palate formation and other fetal abnormalities. If you believe your dog has ingested an overdose of vitamin A, please call your veterinarian or Pet Poison Helpline, a 24/7 animal poison control center, right away.
What are the clinical signs of vitamin A toxicity?
It takes a long time for the clinical signs associated with vitamin A toxicity to develop; symptoms do not usually appear until the dog is at least middle-aged. The most common problem is a form of arthritis in which new bone develops around joints. This leads to stiffness and immobility of the joints; in some cases, the joint may become totally fused. A common site of new bone formation is between the vertebrae of the neck, which interferes with movement of the neck and results in pain and discomfort.
In extreme cases, the dog is unable to move its neck and has difficulty eating. The elbow, wrist, shoulders, and hip joints are also often involved. This can lead to lameness and pain. Owners may notice that the dog cries out when picked up. Many dogs begin to withdraw from contact and spend much of their time hiding. Other clinical signs can include GI disturbances, paralysis, long bone fractures, coagulopathies, and increased liver enzymes/decreased liver function.
Can you get vitamin A poisoning?
Vitamin A toxicity can be caused by ingesting high doses of vitamin A—acutely (usually accidentally by children) or chronically (eg, as megavitamin therapy or treatment for skin disorders). Acute toxicity causes rash, abdominal pain, increased intracranial pressure, and vomiting.