Vitamin A Deficiency
A lack of vitamin A in dogs or cats, usually from an unbalanced homemade diet or poor fat absorption, that can affect vision, skin, and growth.
Also known as Vitamin A deficiency, Hypovitaminosis A, Low vitamin A
Vitamin A is one of those nutrients that quietly runs a lot of your pet's body: it's needed for healthy vision (especially in dim light), for skin and coat condition, for a properly working immune system, and for normal growth and reproduction. Because it's fat soluble, dogs and cats absorb it alongside dietary fat and store some in the liver, which is why both deficiency and excess are possible depending on diet.
A true deficiency is uncommon in pets eating a complete, commercial diet, since these foods are formulated to meet vitamin A requirements. It shows up more often when a pet is fed a poorly balanced homemade or raw diet, or when an underlying illness such as a digestive disorder interferes with fat absorption, since vitamin A can't be absorbed properly without adequate fat digestion. Cats are particularly vulnerable because, unlike dogs, they cannot convert the beta-carotene found in plants into usable vitamin A and must get the ready-made form from animal-based food.
When levels run low, the signs tend to build gradually and can include:
- Difficulty seeing in low light, often the earliest sign, since vitamin A is essential for the eye's ability to adapt to darkness
- A dull, dry, or flaky coat and skin, sometimes with hair loss or an increased tendency toward skin infections
- Dry or irritated eyes, and in more advanced cases, corneal problems
- General weakness or muscle loss as deficiency becomes more severe
- In growing puppies and kittens or pregnant animals, more serious effects on bone development, birth outcomes, and even congenital defects in newborns
None of these signs are unique to vitamin A problems on their own, dry skin or eye irritation can have plenty of other causes, so this isn't something to self-diagnose from a symptom list. If you're feeding a home-prepared diet, or your pet has a chronic digestive condition, or you're just noticing changes in coat, eyes, or night vision, it's worth having a vet look into it. They can assess diet and history and, if needed, run tests to check what's actually going on, since fixing the diagnosis correctly matters more than guessing at a supplement. Correcting a genuine deficiency is usually straightforward once the cause is identified, but it's just as important to avoid overcorrecting, since too much vitamin A, particularly from feeding large amounts of liver or unsupervised supplements, carries its own risks and cats especially are quite sensitive to excess.