Common Dog Food Ingredients That Cause Itching
Itching in dogs can have many causes, but when it's related to food, the culprit is often an ingredient triggering a food allergy. Food allergies in dogs involve an immune system overreaction to certain components, usually proteins, found in their diet. This reaction can lead to chronic itching, infections, and gastrointestinal issues.
Most Common Food Allergens in Dogs
- Beef – 34% of diagnosed cases
- Dairy products – 17%
- Chicken – 15%
- Wheat – 13%
- Lamb – 5%
Less commonly, dogs may also react to soy, corn, egg, pork, fish, or rice. Because these allergens are often shared across many commercial dog foods, identifying the specific trigger can be challenging.
Symptoms of Food Allergies in Dogs
Dogs suffering from food allergies typically demonstrate pruritus (itching) on their:
- Paws
- Face
- Ears
- Belly
- Under the tail
Secondary symptoms may include:
- Recurrent ear infections
- Skin infections (bacterial or yeast)
- Vomiting or diarrhea
- Conjunctivitis
- Hives and sneezing
- Increased bowel movements
Diagnosing Food Allergies
The gold standard for diagnosing food allergies is a veterinarian-supervised elimination diet trial lasting at least 8 to 12 weeks. This involves feeding the dog a strict diet that either contains hydrolyzed proteins or uses novel proteins the dog hasn't encountered before. During this period, no treats, flavored medications, or table scraps should be allowed.
Unreliable Diagnostic Methods
- Blood tests
- Saliva or hair analysis
- Intradermal testing
- Patch testing
These methods are not considered dependable for identifying food allergens. Only a diet trial followed by a challenge phase (reintroduction of suspected allergens) confirms the diagnosis.
Other Factors: Storage Mite Sensitivity
Some dogs may also be allergic to storage mites found in dry kibble. Prevention strategies include:
- Buying only a month’s supply of food
- Storing it in airtight containers
- Keeping food in a cool, dry place
- Freezing weekly portions
- Regularly washing containers
Distinguishing Food Allergy from Food Intolerance
A food intolerance is a non-immune-based reaction, usually causing digestive upset (like vomiting or diarrhea) without skin problems. While the management for both involves dietary adjustments, they differ in underlying mechanisms.
Breed Predisposition
Certain breeds are more prone to food allergies:
- Labrador Retrievers
- West Highland White Terriers
- Boxers
- Cocker Spaniels
- German Shepherds
- Pugs
Immune System Involvement
The immune response may involve IgE-mediated or non-IgE pathways, with some cases involving mixed hypersensitivity reactions. Proteins that resist digestion, such as bovine serum albumin or ovomucoid, are typical allergens.
Management and Treatment
- Lifelong avoidance of identified allergens
- Hypoallergenic diets using hydrolyzed or novel proteins
- Medications to control itching (e.g., Cytopoint, Apoquel, Atopica)
- Antibiotics or antifungals for secondary infections
In some cases, food allergen-specific immunotherapy may be explored, though this remains experimental.
Conclusion
Itching caused by food allergies in dogs is often due to common dietary proteins like beef, dairy, or chicken. Diagnosis requires patience and veterinary guidance through an elimination diet trial. With the right management, most dogs can live comfortably on a carefully selected hypoallergenic diet.
