First Walk is on Us!

✓ GPS tracked walks
✓ Activity reports
✓ On-demand walkers
Book FREE Walk

Jump to Section

What is Iams Allergy?

Iams is a brand name for a variety of cat foods that are made by Spectrum Brands and Mars, Inc. Iams sells food that has been designed by nutritionists and veterinarians for cats and dogs in the following formulas: ProActive Health, Healthy Naturals and Premium Protection. There are also special veterinary formulas available for animals with special dietary needs. 

An allergy will occur when a cat’s immune system responds excessively to one or more of the food’s ingredients. When this happens, your cat’s skin will become itchy and inflamed and he can develop chronic ailments like ear infections and wheezing.

An allergy to a particular food occurs as a result of an overreaction of the cat’s immune system to one or more of the proteins that are present in the food that has been consumed.

Symptoms of Iams Allergy in Cats

Should your cat experience an allergy to a particular food, you may notice skin reactions, often under his front legs, around his face and groin area, as well as between his toes. Symptoms include:

  • Hair loss in patches
  • Rubbing his face
  • Shaking his head
  • Hives
  • Excessive licking
  • Paw biting
  • Skin rashes and infections

Other symptoms can include:

  • Coughing
  • Wheezing
  • Diarrhea
  • Chronic gas

Rarely, an allergy to a food can cause anaphylactic shock, which is life threatening and requires immediate medical attention. Symptoms of anaphylactic shock include:

  • Cold limbs
  • Breathing difficulty
  • Increased heart rate
  • Pale gums
  • Seizures
  • Sudden diarrhea or vomiting


Iams offers a variety of wet and dry cat foods to include:

  • Proactive health
  • Naturals
  • Veterinary formula
  • Purrfect Delicacies
  • Purrfect Delights
  • Purrfect Grain Free

Causes of Iams Allergy in Cats

The majority of your cat’s immune system cells exist in his gastrointestinal system. An allergy to a particular food is activated when your cat’s immune system overreacts to a protein that has been ingested. 

When your cat digests his food, his system will usually break down the foods he has consumed into amino acids, which enterocytes will absorb and transport into his bloodstream. If the proteins he has consumed are not broken down as they should be during the digestive process, the enterocytes look at them as “intruders” and launch an attack on the proteins.

Diagnosis of Iams Allergy in Cats

Should you notice concerning symptoms in your cat, you will want to bring him to your veterinarian. In addition to conducting a physical examination, your veterinarian will ask you for information regarding the symptoms you have observed, when you first noticed them and whether there have been any changes. He will also ask you about any changes in your cat’s behavior, as well as for information regarding his diet, supplements he is taking, and any recent changes.

As your veterinarian will see the issues with your cat’s skin that he is experiencing, he will likely collect samples of the skin cells from any affected areas. These skin cells will be studied under a microscope (called cutaneous cytology) in order to see if mites, yeast infections or other diseases are causing your cat’s symptoms. Should these not be present, your veterinarian will likely consider a food allergy and will recommend an elimination diet, which will help to confirm that there is an allergy and determine what is the cause. Often, an elimination diet will involve changing what your cat eats to bland food made at home or a hypoallergenic commercial product. Your veterinarian can help you choose foods that are not eaten currently by your cat. In the case of a food allergy, within a few weeks on the new diet, your cat’s symptoms will disappear. You can then add individual ingredients back into his diet until you are able to determine which one he is reacting to.

Treatment of Iams Allergy in Cats

While you cannot cure an allergy to a food, your cat’s symptoms should resolve themselves once the food is eliminated from his diet. While you are administering the elimination diet, your cat may still be experiencing some ongoing symptoms of his allergy that can be treated with corticosteroids, which will minimize swelling and antihistamines, which will help with the itching. You and your veterinarian may choose to not minimize his symptoms during the elimination diet, so that it can be clear what is causing the allergy.

Often, when a cat has a rash from a food allergy, his excessive licking and biting can lead to a secondary bacterial infection. Should this occur, an antibiotic will be prescribed to resolve the infection. 

Once you are clear as to what element or elements are causing the allergy in your cat, you will want to be sure that your cat’s diet does not include that item or items. As animals that develop an allergy to one food may then develop additional allergies, it is important to monitor your cat’s reaction to the food that he consumes.

Recovery of Iams Allergy in Cats

As you work with your veterinarian regarding an elimination diet, you will want to be sure that you avoid any ingredients that are present in your cat’s current food. As the allergy may be to a family of foods as a whole, if your cat is currently eating beef, you should consider switching to a protein aside from red meat. While your cat may be tempted by table scraps or treats, it is important that he eat only the foods on the elimination diet so as to best identify the source of the allergy and avoid a reaction.