Two things that look the same but need very different responses.

Allergy and intolerance are used as though they mean the same thing. They do not and the difference matters because treating one when you have the other means staying stuck with the problem for a long time while the dog stays uncomfortable.

A true allergy involves the immune system. The body identifies something, usually a protein, as a threat and responds accordingly. Itching, skin irritation, digestive upset and swelling are all possible responses. Once the immune system is sensitised to a trigger it reacts every time that trigger appears, regardless of the amount involved.

An intolerance does not work the same way. It is more of a processing difficulty. The body struggles to handle a particular ingredient efficiently. The symptoms can look similar but the threshold is different. A dog with an intolerance might manage small amounts of a trigger without reacting but respond to larger quantities. A dog with a true allergy does not have that tolerance window.

Food allergy most commonly involves proteins. Chicken is the most frequently identified, followed by beef and dairy. These also happen to be the most common proteins in commercial dog food which makes them harder to avoid and harder to identify without a proper elimination diet. That means feeding a single novel or hydrolysed protein source strictly for eight to twelve weeks. Any exposure to the suspected trigger resets the whole process.

Environmental allergy is actually more common than food allergy but gets less attention because it cannot be managed by changing the diet. Grass pollen, dust mites and mould are the most frequent triggers. The symptoms tend to be seasonal or environment-specific rather than consistent year-round and they show up primarily on the skin.

For dogs dealing with environmental allergies the most practical ongoing approach is supporting the skin barrier so that allergens have less opportunity to get through. Salmon Oil supports the lipid layer of the skin. Vitamin C and Vitamin E reduce the inflammation driven by allergen exposure. Rusko's Skin & Coat delivers all three at doses that make a real difference. Not a treatment for allergy but daily support for the skin that is being asked to manage more than it should.

Knowing which one you are dealing with changes everything about how you respond to it.