High alkaline phosphatase (ALP) in dogs doesn’t cause symptoms on its own. It’s a lab finding, not a disease, so the symptoms you’ll notice depend entirely on what’s driving the elevation. A normal ALP level in dogs is generally under 140 IU/L, and the signs your dog shows (if any) will vary based on whether the cause is liver disease, a hormonal disorder, bone changes, or something as simple as a medication side effect.
That said, there are recognizable patterns. Certain clusters of symptoms point toward specific underlying causes, and knowing what to watch for can help you have a more productive conversation with your vet.
Symptoms Linked to Liver or Gallbladder Problems
Liver and gallbladder disorders are among the most common reasons for elevated ALP, and they tend to produce the widest range of visible symptoms. Dogs with cholestasis (a condition where bile flow is blocked or reduced) can develop ALP levels 100 times the normal range, especially when the cause is bile duct obstruction, pancreatitis affecting the liver, or liver tumors.
Early signs are often vague: loss of appetite, vomiting, diarrhea, and general lethargy. Your dog might seem “off” without any single dramatic symptom. As liver involvement progresses, more specific signs appear. Jaundice, a yellowish tint visible in the whites of the eyes, the gums, or the inner ear flaps, develops when bilirubin builds up in the blood. You might also notice your dog drinking more water than usual and urinating more frequently.
Gallbladder-specific problems like biliary mucocele (a buildup of thick mucus in the gallbladder) can range from causing no symptoms at all to causing abdominal pain, fever, and in severe cases, shock if the gallbladder ruptures. Dogs with abdominal pain often stand in a hunched posture, resist being picked up, or whimper when their belly is touched.
Symptoms Pointing to Cushing’s Disease
Cushing’s disease (hyperadrenocorticism) is one of the most recognizable causes of sky-high ALP in dogs. About 90% of dogs with Cushing’s have elevated ALP, and the enzyme is often in the thousands, dramatically higher than the other liver values on the same blood panel. The disease happens when a dog’s body produces too much cortisol over a long period.
The symptom picture is distinctive. Dogs with Cushing’s typically develop a pot-bellied appearance as abdominal muscles weaken and fat redistributes. Their coat thins out, sometimes with patchy hair loss, and the skin underneath may look fragile or darkened. Excessive panting is common, even at rest or in cool environments. These dogs eat and drink noticeably more than normal and need to go outside to urinate far more often. Because chronic cortisol suppresses the immune system, recurring skin infections or urinary tract infections are another hallmark. If your dog has several of these signs alongside a very high ALP, Cushing’s disease is something your vet will likely want to investigate.
Signs Related to Bone Conditions
ALP is also produced by bone cells, not just the liver. In growing puppies, ALP is naturally elevated because their bones are actively developing, and this is completely normal. No symptoms come with it, and levels settle as the dog matures.
In adult dogs, bone-related ALP elevation is more concerning. Bone tumors, particularly osteosarcoma (which tends to affect large and giant breeds), can raise ALP levels. The symptoms here are localized: limping or favoring a leg, swelling near a joint, and pain when the affected area is touched. These signs usually develop gradually and worsen over weeks.
Medication-Related Elevations
Steroid medications are a well-documented cause of elevated ALP in dogs. ALP can start climbing as early as two days after beginning a steroid, and it resolves slowly over weeks once the medication is stopped. This applies to oral steroids, injectable forms, and even topical or ear medications containing steroids. The liver changes behind this (called steroid hepatopathy) are typically benign and reversible.
Some anti-seizure medications also raise ALP. In these cases, the dog may have no new symptoms at all. The elevated number shows up on routine bloodwork and looks alarming, but it reflects the medication’s effect on liver enzyme production rather than actual liver damage. Your vet can distinguish this by looking at the full panel and your dog’s medication history.
When ALP Is High but Your Dog Seems Fine
This is more common than you might expect. Mildly elevated ALP with no accompanying symptoms often turns up on wellness bloodwork, especially in older dogs. It can reflect early or slow-moving changes that haven’t yet produced visible signs, or it can be a benign quirk with no clinical consequence.
Breed matters here too. Scottish Terriers, for example, have naturally higher ALP levels than other breeds. One study found that Scottish Terriers without any ALP-associated disease still averaged 1,349 U/L, nearly six times higher than the 228 U/L average in healthy dogs of other breeds. While Scotties do have a higher rate of diseases linked to elevated ALP, their baseline enzyme activity is genetically higher regardless. If you have a Scottish Terrier with high ALP and no symptoms, your vet may take a more conservative approach to workup.
Late-Stage Warning Signs
When the underlying cause of elevated ALP is advanced liver disease, the symptoms become harder to miss. Fluid accumulation in the abdomen (ascites) causes visible swelling and discomfort. Clotting problems can lead to unusual bruising, prolonged bleeding from minor cuts, or blood in the stool. Gastrointestinal bleeding from stomach ulcers is another possibility, since the liver produces the proteins responsible for normal clotting.
The most serious progression is hepatic encephalopathy, a neurological syndrome caused by toxins the failing liver can no longer filter. Dogs with this condition may seem dull or confused, wander aimlessly, press their head against walls, lose coordination, or stop responding to basic commands. Behavior changes like sudden aggression or extreme withdrawal can occur. In severe cases, seizures, collapse, or coma follow. These signs represent an emergency.
What Your Vet Will Look For
A single elevated ALP number doesn’t tell the whole story. Your vet will compare it against the rest of the blood panel, particularly other liver enzymes, bilirubin, and protein levels, to narrow down the source. They’ll also ask about any medications your dog takes, including topical products, and look for the physical signs described above.
Follow-up testing often includes an abdominal ultrasound to visualize the liver and gallbladder, bile acid testing to assess how well the liver is actually functioning, and sometimes ALP isoenzyme testing, which can distinguish whether the elevation is coming from bone, liver, or steroid-induced sources. The specific symptoms your dog shows, or the absence of symptoms, guides which tests make sense and how urgently they’re needed.