Skin allergies are one of the most common causes of itchy skin in dogs. Dogs can be allergic to a wide range of environmental allergens including pollens, grass, moulds, house dust or storage mites and fleas. Symptoms include red itchy skin, recurrent ear infections and overgrooming. Skin allergy treatment is different for each dog and will often involve a variety of medication. Treatment is generally lifelong as this is not a curative condition. Most dogs will suffer from flareups intermittently.
Allergic dermatitis manifests when a dog's skin reacts to something they come into regular contact with. It can start in any dog at any age, but some breeds are predisposed such as WHWs. Finding out exactly what your dog is sensitive to can be really tricky because there are multiple allergens and there's such a wide variety of things that can trigger a reaction. Some allergies can be diagnosed with a blood test, but these are not always reliable.
If your dog has a flea allergy this can often be treated with effective parasite control alone. All pets (not just the one that suffers from the allergy) would need to be treated and medication needs to be given regularly (even in the winter) as in some patients a single flea bite can trigger a reaction.
If you know what your dog is allergic to it is best to avoid these trigger factors if possible. As well as reliable flea control, avoiding long grass or exercising when the pollen count is high can all help reduce allergen exposure. Vacuum, dust, and wash bedding at high temperatures to keep house dust mites at a minimum. Using wet food rather than dry will reduce storage mites.
Most treatments for skin allergies revolve around reducing itchiness. Historically this was done with steroids either by injection, orally or topically. Steroids are very good at suppressing the unwanted immune reaction by the skin so stopping the itching, but they also affect many other parts of the body so have a lot of side effects. We still use steroids but usually in combination with other drugs so we can use them at lower doses and intermittently so reducing the potential side effects.
A commonly used tablet is Apoquel. This helps reduce itching by specifically targeting the parts of the immune system responsible for allergic skin disease and having minimal effect on the rest of the immune system. So, it has far fewer side effects than steroids and is much safe when used long term.
Another drug which can be used long term is Cytopoint. This is given as a monthly injection, and it works by blocking the chemical in the body that triggers allergic itching. In this way it does not suppress the immune system and works in a completely different way. Injections can be repeated every 4-8 weeks depending on an individual's response. Cytopoint is safe to be given to any dog and does not interfere with other medication. The other benefit of Cytopoint is that it does not have any side effects. It can be used in combination with Apoquel if your dog has a flare up or severe allergic dermatitis.
Skin supplements containing essential fatty acids help improve the skins natural barrier. Whilst they are unlikely to be sufficient treatment on their own, they can help reduce other medications.
Daily antihistamines can be useful in some dogs although their effect is not as reliable as it is in humans, they can be safely combined with other medication.