Cats can be lactose intolerant, just like some people.  If you give him milk, it can distress his digestive tract and lead to severe symptoms of gastrointestinal upset.  If your cat is, in fact, allergic to milk, you simply have to remove it from his diet.  With time and perhaps supportive therapies, his gastrointestinal system will calm down and recover.  If you do not remove milk from his diet, his symptoms may worsen and he may become ill.

While we have been taught cats like to drink milk, it is actually bad for them.  If you give your cat milk, consult with your veterinarian on a better option.

Symptoms may include:

Some cats can be mildly allergic to or upset by milk while others have a severe reaction.  Some cats may have runny stools for a time or two, while others may have diarrhea for days and vomit numerous times.  Your cat can also be allergic to milk proteins.  This can mean an allergic reaction to an ingredient in his food, not just straight milk.

Just like humans, cats can be lactose intolerant.  Cats that are lactose intolerant lack the needed enzymes in their digestive system to digest milk.  We are taught through history and cartoons that cats like milk.  While some cats may enjoy it and therefore you want to continue to give it to him, it may not be what is best for him; just like some lactose intolerant people still enjoy their dairy.

When you arrive at the clinic, the veterinary team will begin an assessment of your cat’s symptoms by performing a full physical exam.  This will allow the veterinarian to take a proper look at the clinical signs and rule out possible causes of his condition based on his symptoms.  In addition to the exam, your veterinarian will also collect a verbal history from you including the evolution of the problem, whether it seems to be associated with a season or not,  and whether you have been trying to treat at home with over the counter ointments or medication.   

The veterinarian may go into a detailed analysis of cat’s diet and environment.  She will want to know what he eats for his main food, his treats, any monthly parasitic preventions, or if he could have possibly ingested something from his surroundings, such as dangerous household goods or toxic plants.  This will give her insight as to what your feline interacts with and is exposed to during his day to day routine.

Gastrointestinal parasites will need to be ruled out;  this issue can cause similar symptoms in your cat and will require some basic diagnostic testing in order to eliminate it from the list of causes.  

Unfortunately there is no serum, blood, or intradermal test reliable for diagnosing food allergies.  The only way to come to a food allergy diagnosis is via a food elimination trial.  In this situation, you remove the suspected food item from your cat’s diet for a minimum of 12 weeks; this means no milk. After removing the suspected item from his diet, gastrointestinal signs typically resolve between 1 to 3 weeks. If symptoms continue, then milk is not the cause of his symptoms.  If symptoms resolve, then you need to confirm your suspicion by reintroducing milk to his diet.  During the trial period, all members of the family must comply strictly to the requirements. This means no treats, supplements, or table scraps are permitted.

There is no specific treatment for a food allergy other than to remove the culprit from your cat’s diet.  In the meantime, the veterinarian can offer supportive treatments and therapies in response to the symptoms your cat is suffering.  For example, she can prescribe medications to calm his gastrointestinal tract and decrease inflammation.  There are anti-vomiting and anti-diarrheal medications available to calm his symptoms.  She may also prescribe a probiotic or other supplements to encourage GI health. She may offer him injections of vitamins and administer electrolytes if she feels he needs it from all the digestive upset.  

Finding the source of your cat’s allergy is ideal.  If you are able to determine what it is that is causing your cat’s symptoms and remove it from his diet, he should recover very nicely.

If you do not find and remove the source of your cat’s allergy, you will only be treating and masking his symptoms.  In order to make a full recovery, you will need to determine the cause, in this case milk, and remove it from his diet completely.  While you may enjoy giving him his bowl of milk, it will be better for his health to have it out of his diet all together.  Once removed, his symptoms should subside and he should recover very well.