Allergies in Dogs: Significance and Medical Classification

What does an allergy mean in dogs?

An allergy in dogs is an excessive reaction of the immune system to substances that are normally harmless, whether from the environment, food, or parasites. Clinically, it most often manifests as a skin problem (itching, redness, secondary infections), and less commonly as gastrointestinal symptoms or respiratory issues.

The three most clinically relevant forms of allergy in dogs are flea allergy dermatitis (FAD), canine atopic dermatitis (cAD) caused by environmental allergens such as dust mites or pollen, and food intolerance with an immunological component. Differentiation is important because diagnosis and treatment differ significantly—a generic “hypoallergenic diet” does not resolve either atopy or flea allergy dermatitis. We expressly emphasize that allergy diagnosis belongs in the hands of a veterinarian.

Background + Scientific Context

Canine atopic dermatitis is by far the most extensively studied form of allergy. Olivry et al. (2015) established an international treatment standard with the ICADA guidelines, which addresses acute flare-ups and chronic courses separately. A stepwise approach is recommended: identification and avoidance of triggers, skin care, antipruritic therapy (topical or systemic glucocorticoids, oclacitinib, lokivetmab), and, if necessary, allergen-specific immunotherapy.

For food allergies, the gold standard is a controlled elimination diet lasting at least 8 weeks, followed by a challenge test—according to Mueller & Olivry (2017), commercial allergy tests using blood or saliva are not sufficiently valid for diagnosing food allergies. Flea bite allergy is managed through consistent flea prevention and symptomatic treatment.

Genetic and epidemiological studies, such as those by Hillier & Griffin (2001) and Picco et al. (2008), show that certain breeds, such as West Highland White Terriers, French Bulldogs, and Labradors, have an increased predisposition to atopic dermatitis.

Vitomalia-Position

We recommend a structured diagnostic approach: First, have your pet examined by a veterinarian (skin biopsy, cytology, parasite screening), then proceed with a targeted elimination diet or allergy testing. We recommend patience—elimination diets take at least 8 weeks, often longer. We caution against purchasing generic “allergy food” without prior diagnosis. We caution against online saliva tests, which are not considered scientifically validated (Lam et al. 2019).

We firmly oppose the long-term use of cortisone without veterinary supervision, as well as relying on self-diagnosis when dogs are visibly suffering.

When do allergies become a concern in dogs?

Specific everyday situations in which an allergy should be medically evaluated:

• Recurrent itching – licking paws, rubbing face, scratching belly (see Itching)
• Recurrent ear infections – often the first symptom of atopic dermatitis
• Gastrointestinal symptoms combined with skin symptoms (see Diarrhea)
• Seasonal worsening – a sign of pollen allergy
• Worsening despite flea prevention – differential diagnosis: atopy

Self-medication with home remedies is not appropriate in cases of significant skin changes, secondary infection, or behavioral changes caused by pain.

Practical application

1. Keeping a diary: symptoms, frequency, possible triggers, changes in diet, walking environment—this is a huge help to the veterinarian.
2. Initial veterinary examination: to rule out parasites, bacterial or yeast infections, and hormonal causes.
3. If necessary, an elimination diet: 8–12 weeks on a diet containing hydrolyzed or clearly defined new protein, followed by a challenge test.
4. Atopy diagnosis: intradermal test or serum IgE test for selecting allergen-specific immunotherapy.
5. Treatment according to the ICADA stepwise approach: trigger avoidance, strengthening the skin barrier, antipruritic therapy, and immunotherapy if necessary.

Common Mistakes & Myths

• “Hypoallergenic means allergen-free.” Wrong. Hypoallergenic foods usually contain hydrolyzed proteins—they reduce the risk, but do not guarantee tolerance.
• “Grain-free = allergy-friendly.” Grains are a rare cause. Beef, chicken, and dairy products are more common (Mueller et al. 2016).
• “An online saliva test replaces the vet.” No—these tests have not been sufficiently validated (Lam et al. 2019).
• “A 4-week elimination diet is sufficient.” Olivry & Mueller (2018) show that many dogs need 8 weeks, and some need 12.
• "Allergies usually go away." Not in the case of atopic dermatitis—it is usually a lifelong condition that requires ongoing management.

State of the art in 2026

Research on canine atopic dermatitis has advanced significantly in recent years. According to Moyaert et al. (2017), lokivetmab (Cytopoint), a monoclonal antibody against interleukin-31, has proven to be effective and well-tolerated. The role of the cutaneous microbiome is currently being studied intensively (Bradley et al. 2016). For food intolerance, the elimination diet remains the gold standard—commercial allergy tests are still considered insufficient for diagnosis according to the current AAHA Guideline 2023. Genetic research on breed predispositions is in its early stages.

Frequently Asked Questions

How can I tell if my dog has an allergy?

Recurrent itching, redness, paw licking, frequent ear infections, gastrointestinal issues—either individually or in combination. Diagnosis should be left to a veterinarian.

Does an allergy test help?

For atopic dermatitis, yes (for selecting immunotherapy). For food allergies, no—an elimination diet is the gold standard here.

What food should you feed your pet if you suspect a food allergy?

Hydrolyzed dietary food or a strict single-protein elimination diet, in consultation with the veterinarian. Do not experiment on your own if the diagnosis is unclear.

Can I use home remedies instead of cortisone?

Skin care and omega-3 fatty acids can be helpful (Mueller et al. 2004), but they do not replace medical treatment during an active flare-up.

Related terms

• Atopic dermatitis
• Itching in Dogs
• Food intolerance
• Elimination diet
• Diarrhea
• Complete pet food
• Fleas on dogs

Sources & Further Reading

1. Olivry, T., DeBoer, D. J., Favrot, C., et al. (2015). Treatment of canine atopic dermatitis: 2015 updated guidelines from the International Committee on Allergic Diseases of Animals (ICADA). BMC Veterinary Research, 11, 210.
2. Mueller, R. S., & Olivry, T. (2017). Critically appraised topic on adverse food reactions of companion animals: serum tests for food allergy and food intolerance. BMC Veterinary Research, 13(1), 51.
3. Mueller, R. S., Olivry, T., & Prélaud, P. (2016). Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Veterinary Research, 12, 9.
4. Moyaert, H., Van Brussel, L., Borowski, S., et al. (2017). A blinded, randomized clinical trial evaluating the efficacy and safety of lokivetmab compared to ciclosporin in client-owned dogs with atopic dermatitis. Veterinary Dermatology, 28(6), 593-e145.
5. Lam, A. T. H., Johnson, L. N., & Heinze, C. R. (2019). Assessment of the clinical accuracy of serum and saliva assays for identification of adverse food reaction in dogs. JAVMA, 255(7), 812-816.