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What is Fish Allergy?

Fish is a food that is frequently utilized as a healthy source of protein for felines, although in some cases it can cause dangerous levels of contaminants like mercury to build up in your cat’s system. Some cats may also develop an allergy to fish or shellfish, causing unsightly and uncomfortable skin conditions. In order to reliably determine the proper allergen that is affecting your pet, an elimination diet may be required. This can be time-consuming but is frequently necessary in order to deduce which ingredient is causing the reaction.

Fish and seafood are common ingredients in food and treats that are formulated with cats in mind. For cats who develop an allergy to this food, it can cause an uncomfortable skin condition.

Symptoms of Fish Allergy in Cats

A food intolerance often accompanies and sometimes precedes a full-blown allergy to the food. The intolerance generally presents as gastrointestinal distress and gurgling sounds from the digestive system. Symptoms of food allergies generally start on the head and neck on felines and can include signs such as:

  • Acute moist dermatitis
  • Crusty papules
  • Hair loss
  • Itchy skin
  • Lesions on skin

Types

Food Allergy

An allergy is a response by the body’s immune system to defend itself against something that it perceives as a threat. An allergic reaction from food doesn’t happen the first time an individual is exposed to the ingredient but rather after repeated ingestions. Any food is capable of finding an allergic reaction, but certain ingredients, such as beef, dairy, fish, and eggs tend to cause allergies in felines more often than others.

Food Intolerance

While a food allergy is the immune system responding to a perceived threat, an intolerance to a food has no immune involvement. An intolerance to a food type is more likely to cause a gastrointestinal response than allergies do. Further symptoms, such as gurgling sounds from the digestive system or a change in the consistency or color of the stools are also customary with a food intolerance.

Causes of Fish Allergy in Cats

Allergies, including food allergies, are due to an abnormally intense defensive response to a protein that the immune system views as an invasive substance. It is estimated that around 60-70% of our immune system cells actually reside in the digestive system, and the same applies to our felines. The process of digestion is designed to break down our foods into amino acids, the smallest parts they can be broken down into. These amino acids are then absorbed by a type of immune cell called an enterocyte, specialized white blood cells, and then transported into the bloodstream. When proteins are only partially broken down, the enterocytes see the fragments of food as intruders rather than nutrients, and they attack. Over time the reaction of these cells becomes more and more aggressive, and the symptoms intensify. 

Although allergies can develop to any food, some foods are more likely to generate a reaction than others. Frequent offenders for felines can include:

  • Beef
  • Corn
  • Dairy products
  • Eggs
  • Fish
  • Lamb 
  • Seafood
  • Soy
  • Wheat gluten

Diagnosis of Fish Allergy in Cats

The symptoms related to allergies in felines closely mimic other disorders such as mites or bacterial infections, and will typically prompt the veterinarian to collect skin scrapings as samples to be examined under a microscope, a process known as cutaneous cytology. When the skin cells don’t reveal any other micro-organisms or problems, then an allergy may be suspected. Although both serum and intradermal testing are available for cats with allergies, they are not as reliable for detecting allergies that are related to food. The veterinary gold standard for diagnosis of food allergies is the elimination diet. This diet is implemented by changing the cat’s daily diet to either a limited ingredient or hypoallergenic commercial cat food, or in some cases, to a diet of unseasoned human food. In choosing the proper diet for your allergic cat, novel ingredients are generally required.

Novel ingredients can include any proteins and carbohydrates that are not currently used in the cat’s current diet and preferably ones that have never been introduced. It is of particular importance to check for additional ingredients in commercial diets if you suspect a fish or seafood allergy as fish meal and fish oil are often added to food to increase the amount of omega-3 vitamins. Once signs of the allergy have been eliminated, new ingredients can be reintroduced into the diet one at a time, to uncover which one is triggering the reaction.

Treatment of Fish Allergy in Cats

Revealing the specific allergen that is bothering your pet may require several weeks on the elimination diet, and during this time your cat may continue to experience residual symptoms of the allergy. Corticosteroids are frequently recommended as a way to reduce swelling and antihistamines are often effective at calming itching sensations. Use of either treatment may mask the symptoms of the allergy, however, and this can make it more challenging to single out which ingredient in your cat’s diet is triggering the reactions. Because of this, many veterinary professionals prefer to administer the elimination diet before adding these types of medications to the regimen.

Secondary skin infections are a common occurrence for cats that are experiencing the symptoms of allergies, and antibiotics are usually prescribed to combat and sometimes prevent this particular complication. Once the particular allergen has been defined, this ingredient should be completely eliminated from the cat’s diet and other supplements, including probiotics and non-fish based Omega-3 oils, are frequently recommended for all sorts of allergies as a support to the immune system. This will assist your companion’s body in handling any accidental exposure to allergens and in preventing the cultivation of new allergies.

Recovery of Fish Allergy in Cats

Food allergies are not curable, but symptoms tend to cease fairly rapidly when the allergen is eliminated from the animal’s diet. Any repeat exposure to the allergen can trigger a relapse, so caution should be taken in which treats and flavorings you offer your cat, particularly as fish oil and fish meal are frequently added to products that are not labeled as fish based. Unfortunately, if your feline has experienced an allergic response to one ingredient, then they are more likely to develop allergies to other ingredients as well. The approach to combat this situation varies within the veterinary profession, with some doctors advocating that your cat remain on a single source of food, while others maintain that a steady rotation of three of four foods with proteins is optimal.

Fish Allergy Questions and Advice from Veterinary Professionals

Newman
Sphynx
9 Months
Mild condition
0 found helpful
Mild condition

I’m babysitting a cat who just started becoming sick. He eats a raw diet and just switched him from beef to turkey( end of the container) he also swiped some of my dry cat food. He started vommitting yesterday but still cried for food. He got sick again later than night after eating. Around midnight I gave him a teaspoon of food and anti vommitting medication. Around 5 am he woke me up vommitting again. What should I do? His mother recently had him to the vet and thinks it could be a chicken/fish allergy.

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3314 Recommendations
Try withholding food for 12 hours to see if a break in eating helps, give small quantities of his normal food; however if there is an allergy or intolerance you’ll need to wait for the effects of the allergen to wear off. Other causes of vomiting may include foreign objects, infections, parasites among other causes; keep an eye on Newman for the time being and if there is no improvement after a day you should visit a Veterinarian to be on the safe side. Regards Dr Callum Turner DVM

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Chloe
Mixed breed
10 Years
Serious condition
0 found helpful
Serious condition

Has Symptoms

Losing fur, skin is loose

Chloe’s fur is falling out and irritated. She is licking it. Skin is red and inflamed. She is eating some but is less social and hiding. Her blood work is normal. Has seen several vets. Has an appointment with animal dermatologist on Friday. Was given a pain relief shot today. No one knows what it is. She eats quality food and has glass bowls. Indoor cat.

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3314 Recommendations
It can be difficult to narrow in on a specific cause for fur loss especially in an older dog; hormonal conditions, allergies, nutritional deficiencies, psychological disorders (excessive grooming) among other causes may lead to fur loss. You should consult with the Dermatologist and see what they find. Regards Dr Callum Turner DVM

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Buddy
DOMESTIC
9 Years
Moderate condition
0 found helpful
Moderate condition

Has Symptoms

Constant scratchng

Medication Used

Vet gave me fish oil capsules

Buddy was scratching a lot. Took him to the vet. Vet noticed dry skin, looked like dandruff. Vet gave me fish oil capsules to put on his food. He hates it. I have to put in a syringe and give it that way. His litter is unscented.he is still scratching and shakes his head. Vet checked ears and they are fine

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3314 Recommendations
There are many causes for a cat to be scratching themselves which may include allergies, infections, parasites, neurological disorders, chemical irritations among other causes; try feeding a limited ingredient diet for a few weeks to see if there is any improvement and think about any changes in the home (new detergents etc…) which occurred before the scratching started. Regards Dr Callum Turner DVM

Thank you. I bought him different food. No grain or soy. Natural food. Nitro brand. Adding a little with his current food until he's just getting nitro.

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Serenity
domestic short hair
13 Years
Mild condition
0 found helpful
Mild condition

Has Symptoms

Irritations and swelling of mouth

My car is on a prescription diet for thyroid issues. I was told I could introduce fish oil to help with her dander.
I did that and it seems as though she’s had an immediate reaction. Her lip area swole up with what looks like sores. She lets me touch them and is still eating and drinking normally. I have removed the fish oil. Can I give her Benadryl?

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3314 Recommendations
For allergies in cats it is best to give 5mg of cetirizine one per day (you should consult with your Veterinarian first since antihistamines may have a negative effect on some cats with certain thyroid issues), obviously withhold the fish oil and think about alternatives as there are some plant based (seaweed derived I think) sources of omega oils. If the swelling doesn’t go down, visit your Veterinarian; other causes may be insect bites, self trauma or other allergies. Regards Dr Callum Turner DVM

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Bubbles
Turkish Van
6 Years
Moderate condition
0 found helpful
Moderate condition

Has Symptoms

overweight
Vomitting

Medication Used

12 hours fasting
No medications prescribed

My cat Bubbles is overweight. We are feeding him dry cat food. As per vet’s advice, we gradually changed to boiled fish(mackerel). But he vomits every time we feed him fish. Please suggest remedy

Dr. Michele King, DVM
Dr. Michele King, DVM
1604 Recommendations
Without seeing Bubbles or knowing why he was transitioned onto a mackerel diet, it would be irresponsible of me to suggest an alternative. It would be best to call your veterinarian, let them know that the fish diet isn't agreeing with him, and ask for alternatives, as they are aware of his specific health conditions.

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Ginger
dsh
7 Years
Mild condition
0 found helpful
Mild condition

Has Symptoms

Itchiness
Lesion

We suspect our female cat who is white with orange spots is allergic to fish and are having a hard time finding wet food she can and/or will eat; Do you have any suggestions? Along with itchiness she has or had redness and lesions on skin.

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3314 Recommendations
There are many non-fish cat foods out there, but you need to make sure any oils are derived from plants and not from fish as this may cause a reaction; you should visit a pet shop in your area as there may be offerings from local or small pet food companies which I find usually is the case with specific dietary issues like this. Regards Dr Callum Turner DVM

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Max
Feline
3 Years
Moderate condition
1 found helpful
Moderate condition

Has Symptoms

Excessive Shedding
Excessive Shedding,shedding,enough.
Excessive scratching

Medication Used

Solucortex

My cat was scratching has had a steroid shot about every 3-4 months.So I said let’s just do the allergy test.Drew his labs came back allergic to mixed fish and chicken.Whats left to feed him?Tried rabbit and he’s not too fond.Thanks.

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3314 Recommendations
Fish and chicken diets are the cornerstone of many different feline diets; however there are other protein sources available including rabbit, duck, venison, kangaroo or using a hydrolysed protein diet. You should discuss the offerings your Veterinarian has at the clinic and check your local pet shop. Regards Dr Callum Turner DVM

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Elvira
domestic short hair
8 Months
Moderate condition
0 found helpful
Moderate condition

Has Symptoms

Loose Bowel Movements
Loose Bowel Movements diarrhea

I got my cat a month ago from a pet cafe and she's had diarrhea since I've had her. She's been eating purina one salmon flavor at the cafe. After 2 weeks I took her to the vet and they tested her poop which came back negative for parasites, giardia etc. they gave me a dewormer and probiotic which she's done with. I switched her good to taste of the wild and it's been 1.5 weeks with no better results. I am stressed and need another opinion.

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3314 Recommendations
There are various causes for diarrhoea and it may be that Elvira is stressed, other causes apart from parasites are infections, poisoning, colitis, dietary sensitivity among other causes. You should try moving to a restricted ingredients diet to see if there is any improvement; also there may be something in your home which is causing diarrhoea. Regards Dr Callum Turner DVM

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Freya
Burmese
8 Months
Serious condition
0 found helpful
Serious condition

Has Symptoms

Diarrhea

What can i give my cat if she accidently ate fish she is alergic to. Ive taken her twice to a vet witch has cost me a lot of money and i did not get any answers. After she ate snoek again for the 3rd time i realised she is alergic to snoek. She dont get sick after eating tuna.

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3314 Recommendations
If you’ve identified that Freya is allergic to pike (snoek), you shouldn’t purchase it and stick with fish you know is safe; it is always best to limit the exposure to allergens. Regards Dr Callum Turner DVM

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Dude
domestic short hair
3 Years
Serious condition
1 found helpful
Serious condition

Has Symptoms

Licking belly arms legs bald
Licking belly arms legs and back

How do i tell? Ive been feeding him salmon food his whole life and this just started a year ago. Ive switched brands but never proteins. Hes on blue buffalo wilderness salmon. Ive been reading and thinking about switching to blue buffalo basics since its a single protein source and trying either duck or turkey. Any advice?

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3314 Recommendations
Allergies can be difficult to pin point, especially when they are food origin; if you have noticed symptoms of allergies after changing the food, you should change back to the previous brand for a few weeks to see if there is any improvement. The shortcut way would be to have allergy testing done by your Veterinarian since the source of the allergy may not be protein. Regards Dr Callum Turner DVM

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Gracie
Maine Coon
6 Years
Moderate condition
2 found helpful
Moderate condition

Has Symptoms

Pulling fur out of tail

I have a six-year-old (indoors only) female Maine Coon cat who, in the last year or so, has started pulling her fur out of her tail. Her once beautiful fluffy tail is now so skinny! She is not biting her skin, which looks fine. I took her to the vet a few months ago and the vet gave her a steroid shot which seemed to help a bit, but the vet isn't sure what's going on. She's still pulling fur out and she wants me to scratch her face a lot. She has a sibling cat who is fine. There are no fleas. I don't use scented cat litter. There have been no changes in the house that might account for psychological problems. I'm thinking it might be a food allergy, so thought I'd try eliminating any cat food that has fish in it (which she has been eating all her life). She gets wet and dry food. I've made sure to read labels so there's no fish listed, but I'm just guessing that fish cat food might be the problem. She's eaten both fish/seafood cat food, as well as chicken, etc., all her life with no problems. Any advice? Thank you.

Dr. Michele King, DVM
Dr. Michele King, DVM
1604 Recommendations
Environmental allergies are much more common that food allergies in animals, and it can be difficult to get to the bottom of itchy skin. She may benefit from medication for allergies, such as Apoquel or CADI injections, or she may need a hypoallergenic food if she has food allergies, as it can be very hard to identify the cause of the problem. Since allergies and itchy skin can be so difficult to resolve, it might be best to work closely with your veterinarian to identify a therapy that works.

Thank you! :)

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