What to Do When Your Dog Is Too Thin
📝 Summary
A thin dog either eats little (infection recovery, parasites, mouth disease, tumors) or eats well yet wastes (poor nutrition, parasites, maldigestion, kidney failure, diabetes). A fecal test and blood work find the cause; treat that, not just the weight.
1 Poor appetite with weight loss
This pattern points to conditions that kill the urge to eat or block nutrition: the recovery phase of distemper, parvovirus, or infectious hepatitis; heavy gut parasites (coccidia, tapeworm, hookworm) that damage the intestinal lining; mouth disease such as tooth-root abscess, periodontitis, or oral ulcers; and malignant tumors of the nose, mouth, eye, liver, or kidney that cause whole-body decline.
2 Good appetite yet still losing weight
When a dog eats well but stays thin, nutrients are being lost or not used. Causes include poor nutrition (too little food or low protein), gut parasites (roundworm, hookworm, coccidia, Giardia) that steal nutrients, poor digestion from enteritis or low bile or pancreatic juice, chronic kidney failure that loses protein in urine, diabetes (thirst, urination, hunger, and sugar in urine), and excess exercise, poor environment, or widespread eczema.
3 Next steps
A vet visit with a fecal test and basic blood work separates simple underfeeding from parasites, diabetes, or organ disease. Treat the cause, not just the scale, and the weight should follow.
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