Itchy Cats and Dogs

Catherine Lenox, DVM, CVA, Diplomate ACVN

Scientific Affairs Manager, Royal Canin USA

Skin problems are among the most common reasons cat and dog owners seek veterinary advice.  Itchy cats and dogs have a decreased quality of life due to the discomfort associated with skin issues.  Some owners even notice their pet scratching in the middle of the night, which can cause issues for the entire family.

Other signs that you or your veterinarian may notice in your itchy pet can include:
  • Ear infections
  • Redness of the skin
  • Wounds associated with scratching (“hot spots”)
  • Secondary infections
  • Hair loss
  • Gastrointestinal signs such as vomiting and diarrhea (associated with adverse food reactions)
Skin issues can have a number of different causes.  The most common causes of skin problems in cats and dogs are flea allergies, atopic (environmental allergies), and adverse food reactions, these and other causes, such as a skin infection, should be ruled out by a veterinarian.

Flea allergies can be quite severe, even if fleas are not seen on the cat or dog.  Pets with flea allergies are usually very itchy.  Use of flea prevention products under the direction of a veterinarian can help prevent itchiness associated with flea allergy dermatitis.  Environmental treatment may also be necessary in order to eliminate signs associated with flea allergies, such as special cleaning techniques.

Atopy is often a diagnosis of exclusion.  This means that adverse food reactions, flea allergy dermatitis, infection, and other causes of skin problems may have to be ruled out before the problem is attributed to environmental allergies.  Cats and dogs can also be tested for environmental allergies with either an intradermal skin test or a blood test.  Environmental allergies can be treated with a combination of medications, environmental changes, and dietary modification.  Antihistamines, corticosteroids, and allergy injections are examples of medications that can be used to treat atopic patients.  Other changes, such as wiping a dog’s feet after he or she has been outdoors to eliminate allergens from the skin, can also be useful in the management of atopy.  Nutritional management of atopy can include a combination of nutrients to help the skin barrier function better to keep allergens out of the skin, omega-3 fatty acids from fish oil to help with inflammation, and treating concurrent adverse food reactions if present.

Adverse food reactions can occur in conjunction with flea allergy dermatitis and/or atopy, or can occur as the sole cause of dermatologic and/or gastrointestinal problems in a patient.  If other skin conditions are present, the best response to therapy occurs when all problems are addressed.

Adverse food reactions include both food allergy and food intolerance.  A true allergy is mediated by the immune system while food intolerance is not.  A good example of a food intolerance that is not an allergy is lactose intolerance; in people and animals with lactose intolerance, the problem lies in the capacity to digest lactose but there is no actual allergy.  Signs associated with adverse food reactions can include both skin and gastrointestinal signs.  Many animals with adverse food reactions have the skin signs listed above in addition to vomiting and/or diarrhea, while other animals will have skin signs or gastrointestinal signs, but not both.  Adverse food reactions are diagnosed with a food elimination/challenge trial.

A food elimination/challenge trial includes removing all potential food allergens including the main diet, treats, human foods, food used for medication administration, flavored medications, and even toothpaste from the pet’s diet for a predetermined period of time to see if there is a response to dietary modification.  Pets with skin signs can take up to 12 weeks to show improvement during a diet trial, while pets with gastrointestinal signs alone usually respond within four weeks.  During the trial, a hydrolyzed protein diet or a veterinary exclusive novel protein diet should be used.  These diets can help alleviate clinical signs if adverse food reactions are present because they are less likely to stimulate an allergic response.  Hydrolyzed protein diets contain proteins broken down on a molecular level to avoid stimulation while novel protein diets contain protein sources to which the animal has not been exposed, making the likelihood of allergy or intolerance less likely.  After the trial is complete and if the pet responded, the cat or dog should be “challenged” with the suspected allergen or previous diet to ensure that clinical signs improved due to the diet change and not due to another medication or changes in environmental allergens during the trial.  If the animal responds in a negative manner to the challenge, the diagnosis of adverse food reaction is confirmed.  If that occurs, the hydrolyzed protein or novel protein diet should be used long-term.

 

VISIT YOUR VET

The causes of skin issues including itchiness can vary widely.  Only a veterinarian can diagnose, treat, and make nutritional recommendations for a pet with dermatologic disease.  Nutrition can play an important role in management of both atopy and adverse food reactions.  For adverse food reactions, a new diet is used to help diagnose the problem.  If your pet needs a food elimination/challenge trial, the diet used and additional recommendations can be obtained from your veterinarian.


TIPS TO TAKE AWAY

  1. The most common causes of skin problems in cats and dogs are flea allergies, atopic (environmental allergies), and adverse food reactions. 
  2. Cats and dogs can also be tested for environmental allergies with either an intradermal skin test or a blood test. 
  3. Environmental allergies can be treated with a combination of medications, environmental changes, and dietary modification.