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What you‘ll find in this article:

What ‘allergy’ really means 

A true allergy is an immune overreaction to something typically harmless, often referred to as a ‘trigger’ - things like certain food proteins, pollen, or dust. When the body encounters these triggers, the immune system produces antibodies (known as IgE antibodies), that bind to immune cells. The immune cells release histamine, which causes itching, redness, swelling and irritation - this is what owners see as scratching, paw licking, or ear shaking. 

Sensitivities on the other hand, whilst they look similar in their presentation, do not involve this same IgE-histamine pathway. They tend to cause mild gut or skin upset, rather than a full blown immune response.

Research shows that up to 20% of itchy dogs seen by vets have an allergic cause, so it’s surprisingly common in our dog population. Atopic dermatitis, a term used for different types of skin inflammation, typically characterised by itchiness, redness and a rash, is the most common vet presentation (1).

Common signs of allergies in dogs

Unsurprisingly, the most common ‘signs’ are scratching/itching, paw licking, red patches, chronic runny eyes and repeated ear infections. Some dogs get soft or loose stools, or frequent bloating and tummy noises. The pattern of these allergic signs - whether they’re seasonal or year-round - can give your vet clues as to what might be the trigger. The BSAVA Dermatology Manual suggests that allergic skin conditions often appear between 1-3 years of age, and may worsen seasonally (1), whether the trigger is seasonal or not.

How the gut and immune system are connected

A large proportion of immune cells are associated with the gut (5, 6, 7, 8), which is why the digestive system gets so much attention in animal health. When the gut microbiome is out of balance, the immune system can overreact to otherwise harmless triggers. There is research evidence to show that probiotics can modulate immune markers (i.e. keep the immune system balanced), and support skin barrier health in dogs with allergies conditions (2, 5). 

Supportive nutrients that can help

There is growing evidence that certain probiotics may help maintain a balanced gut microbiome and support normal immune responses. Omega-3 fatty acids have also been reported to reduce itch scores, and improve coat condition in dogs with allergic skin disease (3, 7), alongside things such as Zinc and Biotin.

Antioxidants, such as Vitamin C and Vitamin E, selenium and polyphenols, can help to reduce oxidative stress during flare-ups (i.e. deal with inflammation more smoothly). In one particular study, antioxidant supplementation was associated with improved measured immune responses to vaccination (8): in other words, whilst it didn't make the vaccine 'better', the dogs showed slightly stronger immune reactions when they were vaccinated, after supplementation.

Choosing the right supplement

Supplement choice can be overwhelming, and whilst supplements themselves do not replace professional diagnosis, they can help to maintain comfort. Evaluate supplement labels for transparent and clear declared active ingredients (4), minimal artificial flavourings or useless additives, and clear traceability. Introduce any new supplements gradually, one at a time, and keep a record of changes in your dog’s condition and wellbeing. 

When to see your vet

Veterinary dermatologists recognise that only diagnostic testing confirms allergy triggers (2), but constant ear scratching, head shaking, sores or red patches, persistent tummy upsets or loose poops may indicate your dog requires attention from your vet. They can run skin tests, or elimination trials, to identify triggers.