Skin Issues in Dogs: How to Tell If It’s Food, Fleas, or the Environment

If your dog has skin issues, you probably know how frustrating it can be. Not only is it distressing to see them irritated, sore, and restless, but their constant scratching stops you both from getting much-needed rest.

Allergies are one of the most common causes of skin problems in dogs. Dog skin allergies can be caused by three main categories: food, fleas, or environmental allergens. In this article, we’ll break down these three categories, including how to spot the signs and what to do about them.

Skin Issues in Dogs: Facts

• Around 20% of dogs experience ongoing or seasonal skin irritation or itching caused by allergies.
• The most common causes of allergic skin disease in dogs are food, fleas, and environmental allergens.
• Several tests are often needed to find the cause of a dog’s skin disease.
• Skin allergies cannot be cured, but symptoms can usually be managed.

Skin Issues in Dogs: Signs and Symptoms

If your dog has skin problems, here are a few signs you might notice:

• Persistent scratching, chewing, or licking
• Redness, scabs, or flaky skin
• Hair thinning, broken fur, or bald patches
• Greasy or smelly skin or oozy sores
• Pigmented areas or skin that’s thickened and wrinkly
• Ear infections, smelly ears, or head shaking
• Scooting or paying extra attention to their rear

Allergic skin disease commonly affects certain areas of the body. However, not every area will be affected every time, and the location of the sore or irritated skin can sometimes give a clue about the underlying cause.

Causes of Skin Issues in Dogs

Food Allergies

The most common food allergens are chicken, beef, and dairy. If your dog has food allergies, they normally develop itchiness or a rash affecting their ears, paws, or face. They might also be prone to recurring ear infections or interdigital dermatitis (itchy and sore skin between their toes). As well as skin problems, they might also suffer from gastrointestinal symptoms, like vomiting, diarrhea, or gas. The itching is often continuous, or any flare-ups do not follow a seasonal pattern, and symptoms don’t respond to strict flea control, making a food allergy the more likely diagnosis.

If you and your vet suspect that your dog may have a food allergy, try an elimination diet for 5 to 8 weeks. This involves choosing a novel protein source that your dog hasn’t eaten before (like duck or venison) or a prescription hypoallergenic diet. It’s really important to be aware that although many pet food brands will use the term ‘hypoallergenic’ or ‘allergy food’, this isn’t always the case. If the symptoms have resolved at the end of the trial, gradually add in other foods one at a time, with two weeks or more between to help you identify a trigger if symptoms return.

Fleas (flea allergic dermatitis)

You might assume that if your dog’s skin problems are caused by fleas, you’ll see them in their fur. However, just one flea bite can cause an excessive reaction in dogs with a flea allergy, so you may only see flea dirt (flea poop that looks like tiny black specks in the fur). Flea bites cause dogs to be intensely itchy, leading to hair loss, broken fur, and sores caused by self-trauma. Commonly affected areas are the rump, tail-base, and along the spine, and you might be more suspicious of a flea cause if you have other pets who are itchy or family members are getting bitten.

If your pet has fleas, wash all bedding and removable soft furnishings on a hot wash and use a household flea spray on carpets and floors. Treat all pets in the household with a vet-approved product and prevent licking and self-trauma with a cone collar.

Environmental Allergies (atopic dermatitis/atopy)

Environmental allergies (caused by pollen, house dust mites, storage mites, molds, etc.) often cause itchiness and redness of the ears, armpits, groin, paws, and belly. Depending on the allergen, you might notice a seasonal pattern to the symptoms, or that your dog’s skin is itchier or more inflamed after a walk or after being indoors. As with any allergy, dogs aren’t born with environmental allergies. Instead, symptoms usually start in young adulthood (1-3 years old).

To help manage your dog's environmental allergies, use a damp cloth to wipe your dog’s paws after they’ve been outside, store kibble in air-tight containers, and vacuum floors and hot-wash soft furnishings regularly. Because it’s so hard to completely prevent your dog from being exposed to allergens in the environment, your dog may need medication from the vet to control their symptoms.

Diagnosing Dog Skin Problems

Dogs can be allergic to more than one allergen – sometimes allergy tests reveal 3 to 8 allergens or more, although not all of these tests are particularly reliable. As well as the possibility of more than one allergy, a dog’s skin issues can also be multi-factorial. For instance, skin that is already inflamed due to an allergy will have a disrupted skin barrier, allowing bacteria or yeast to penetrate and cause an infection. This is why investigating the cause of dog skin problems can take time, with multiple tests and more than one treatment required.

As well as a head-to-tail examination, your vet might suggest the following to investigate your dog’s skin problems and find the most effective treatment:

• A skin scrape or examination of samples under the microscope (checking for parasites, bacteria, and yeast).
• An elimination diet in case of a food allergy.
• Allergy testing via a blood test or skin prick test.

Treatment and Management

Fleas

If your dog has fleas, every pet in the household should be treated with a vet-approved flea treatment, and the household should be treated with a spray. If your pet has caused an infection or self-trauma, additional medication might be necessary.

Environmental Allergies

Most dogs with atopy are treated with anti-allergy medication, like oclacitinib (Apoquel) or monoclonal antibody (Cytopoint). However, steroid medication, antihistamines, and immunotherapy can also be effective.

Food Allergies

Dogs with food allergies need a restricted diet - either a prescription hypoallergenic diet or a nutritionally complete diet that does not contain ingredients to which they are allergic.

Infections

Bacterial infections or yeast overgrowth may be treated with medicated shampoos, antibiotics, or antifungal treatment.

Home Care

To keep your dog’s skin as healthy as possible and reduce allergy flare-ups, protect your pet with a vet-approved parasite control. Consider giving them omega-3 fatty acid supplements to support skin barrier function and maintain regular home-cleaning to reduce allergens.

If your dog’s skin is sore, smelly, or persistently itchy, it’s important to take them to the vet.

FAQs

Summary

Many skin issues in dogs are caused by allergies to food, fleas, or environmental allergens, and these conditions can be time-consuming to diagnose and frustrating to manage. However, with the right advice and treatment, your dog can enjoy a good quality of life with healthy, comfortable skin.

Dr. Hannah Godfrey BVetMed MRCVS

Hannah graduated in 2011 and works as a small animal vet in Cardiff, UK. She loves meeting people and their special pets and has a particular interest in diagnostic imaging, soft tissue surgery, and dentistry.

Feature image: istockphoto