Seafood Allergy in Cats

Many cat foods and cat treats include seafood in their ingredients. Often used as a healthy source of protein in food for cats, an allergy can occur when a cat’s immune system overreacts to a protein that is present in the seafood. Like other food allergies, an allergy to seafood can lead to an uncomfortable skin reaction for the cat. 

Once your veterinarian thinks that your cat is experiencing an allergy to a particular food, an elimination diet will be recommended in order to confirm which protein your cat is reacting to.

An allergy to seafood will occur when the immune system of a cat overreacts to one or more of the elements present in the food that he consumed.

Should your cat experience an allergy to seafood, symptoms will likely be similar to those of other food allergies and will include: 

• Skin symptoms often starting at your cat’s head and neck
• Scratching, biting and/or licking his skin
• Hair loss
• Skin rashe
• Blisters/lesions or skin ulcerations
• Swelling in his face and limbs
• Hives
• Inflammation in his paws

Some cats can have respiratory symptoms like coughing or trouble breathing. Gastrointestinal symptoms like diarrhea and vomiting are also possible, as well as chronic ear infections and lethargy.

Types 

Your cat may experience a food intolerance before or during the appearance of the allergy. When your cat is displaying a food intolerance, it will often involve gastrointestinal distress and gurgling sounds from his digestive system. When a food allergy occurs, in many cases it will start on your cat’s head and neck and you will likely see hair loss, skin lesions and itchiness.

The majority of your cat’s immune system cells are in his gastrointestinal system. Should his immune system overreact to a food he has consumed it is considered an allergy. Upon digesting what he has consumed, your cat’s system will break down the food into amino acids that will be absorbed by enterocytes and taken into his bloodstream. If the proteins are not broken down as they are intended, the enterocytes will think that they are intruders and this will cause them to attack, leading to the allergy response. 

An allergy can develop to any food, though some are more likely to cause a reaction in your cat. In addition to seafood, some other foods that commonly result in an allergic reaction when consumed include:

• Lamb
• Eggs
• Fish
• Beef
• Corn
• Dairy

Should you notice concerning symptoms, you will want to bring your cat to the veterinarian for a check-up. After a full physical examination, your veterinarian will ask you about when you first noticed symptoms in your cat, and what changes have occurred. Your veterinarian will also inquire about your cat’s diet and any supplements he takes.

Your veterinarian will likely recommend having blood work done to show how your cat’s internal organs are performing. A packed cell volume or PCV can be taken to make sure your cat is not dehydrated. A sample of your cat’s skin cells will be taken and looked at under a microscope, which will help your veterinarian rule out parasites, yeast and bacteria. 

Once your veterinarian has ruled out other causes of your cat’s symptoms, a food allergy will be considered. To confirm this (and what the allergy is to) your veterinarian will recommend that your cat be put on a novel diet which will usually consist of a very bland diet that is different from what he has been eating.

The diet should be followed for at least 90 days; should his symptoms resolve themselves while on the diet, it will point to his having an allergy to something that he has consumed. After around 90 days of the diet, you can start reintroducing things he had previously eaten, like seafood, one at a time. Should your cat’s symptoms return, you will be able to confirm what it is your cat is allergic to.

Once an allergy to seafood is confirmed, it will need to be kept out of your cat’s diet. While your cat is on the novel diet, he will initially have symptoms of the allergy. These can be relieved through antihistamines (though they don’t work for all cats) or corticosteroids. Both antihistamines and corticosteroids can help with itching and swelling.

While your cat will gain some relief from these, masking the symptoms of the allergy may make it harder to determine what aspect or aspects of their food are causing the reaction. For this reason, your veterinarian may recommend avoiding these medications while you administer the novel diet. If your cat develops a secondary infection due to excessive licking and biting, your veterinarian will prescribe antibiotics to resolve it.

Once it has been confirmed that your cat is allergic to seafood, it is important to remove it from his diet, after which his symptoms should resolve themselves. Cats with one food allergy frequently develop additional allergies so it is a good idea to keep a close eye on your cat for symptoms down the road.