Dermatitis in Dogs

What is dog dermatitis?

Dermatitis in dogs is a general term that encompasses the many symptoms of skin conditions in dogs. Together we will address what to look for to identify dermatitis in dogs, the most common causes, how to treat it, and how to prevent canine dermatitis. This knowledge and your veterinarian can facilitate a faster diagnosis and treatment plan and get rid of that itch.

When we break dermatitis down, it plainly means, inflammation of the skin. “Derm” is skin, and “-itis” is inflammation. Dermatitis, or skin inflammation, in our dog friends commonly presents as intense itching, redness, inflammation, and rash.

Types of Canine Dermatitis:

Atopic Dermatitis 

Also known as allergic dermatitis, atopy is a hypersensitivity or overreaction to common substances in the environment. These allergens could be pollen, dust, grass, food, or even human skin cells.

There are so many environmental allergens it can be difficult to determine the cause of canine atopic dermatitis or allergic dermatitis. Atopic dermatitis is characterized by licking of the paws, legs, hind end, or face. Atopic dermatitis in dogs can cause them to develop chronic ear infections, a skin infection, anal gland issues, and more.

Acral Lick Dermatitis

As the name suggests, licking is the main culprit in this type of dermatitis. These lesions are also called lick granulomas. They are often found on the front legs of dogs. The underlying cause is usually a food allergy, environmental allergy, parasites, osteoarthritis, or behavioral issue. Common features of lick granulomas caused by dog dermatitis are hair loss, redness, and thickening of the skin.

Pyotraumatic Dermatitis 

This is the official term for our very common canine dermatitis, the hot spot. Anyone who has had a golden retriever or lab will tell you exactly what this is. Hot spots are caused by moisture getting trapped under the hair coat and causing the underlying skin to become irritated and inflamed. This quickly leads to infection either from the environment or from the dog’s mouth. The infection causes intense pruritus, and the dog’s primary defense is to lick.

Hot spots can literally form overnight, especially when a dog is left unsupervised, and lick that one area incessantly. A hot spot can also be created by fleas, food allergies, grooming incidents, behavior issues, and any other causes that a dog may be itchy, leading to canine dermatitis. Distinct characteristics of a hot spot include red, oozing, wet superficial skin that has a foul odor. Often the hair surrounding the lesion is matted and laying over a scabbed-up lesion.

Parasitic Dermatitis 

Fleas, mites, ticks, and other ectoparasites can be the cause of dermatitis in dogs. Whether it’s allergies (see flea allergy dermatitis) or allergic reactions to the parasite. We often see hair loss around the eyes, under the arms, and along the back. Determining the parasite and treating appropriately can allow these dogs relief quickly.

Malassezia Dermatitis 

Affectionately known as “Yeasty Beasties”, Malassezia is a peanut-shaped yeast often found in skin infections. We commonly think of them as secondary pathogens that are contributing to dermatitis, but they can be the primary pathogen as well. Yeast can also be found in ear infections. They are a big reason why your veterinarian may want to do further diagnostics to determine the best way to treat yeast infections.

If we don’t know that Malassezia is present, we may use an antibiotic option and not deal with the yeast. This means the dog may get better for a bit, but the yeast will cause recurrent yeast infections quickly. Malassezia dermatitis is characterized by crusty, scaly skin with a foul odor and hair loss.

Honorable mentions include contact dermatitis, bathing furunculosis, autoimmune conditions, and metabolic conditions leading to changes in the skin.

Your veterinarian may need to perform diagnostics to determine the cause of your dog’s dermatitis. As you can see above there are so many underlying causes and many of the conditions have overlapping symptoms. Diagnostics allow us to direct treatment in a more targeted way and increase success rates as we treat secondary skin infections or treat allergic dermatitis, depending on the cause.

What Causes Dog Dermatitis

Flea Allergy Dermatitis – Fleas are one of the most common reasons we see dogs in veterinary medicine. It is always the first thing that needs to be ruled out when dealing with an itchy dog. Many times, we can actually find a flea or evidence of a flea. Flea dirt is dark and dirt-like and can be combed off and placed on a paper towel. If you add a drop of water, you can see the dirt change to red due to blood from the fleas.

One thing that owners need to remember, your dog can have an allergic reaction to fleas without the presence of an actual flea. Some dogs are so allergic and when a flea is anywhere near them, they will have an inflammatory reaction. They become intensely itchy and will lick, scratch, and rub to try to relieve the itch, which can cause hot spots and secondary skin infections.

Common areas to find fleas are along the belly, around the tail, and above the eyebrows.

Diagnostics include but are not limited to:

• A good physical exam – Identifying lesion distribution and evaluating the whole dog is paramount.
• Skin Cytology – A slide is used to gather impression smears of the skin. This can identify bacteria, fungi, and parasites.
• Skin Scrape – Mites like to burrow deep into the skin. A scrape allows us to evaluate for mites.
• Skin Biopsy – Samples of skin can be submitted and evaluated for cell types, neoplastic cells, and more.
• Hair Trichogram – Hair is obtained from skin lesions and evaluated for infection or parasites.
• Fungal/Bacterial Culture – Tissue or exudate is obtained and plated on culture media. These plates are then monitored for bacterial/fungal growth, and we can determine what treatments are best.
• Intradermal Skin testing – Allergic dogs can be tested for common allergens, like flea allergies or common food allergies. Once their allergens are determined, treatments can be produced.

Once you have a diagnosis, you are on your way to getting your dog feeling better. Treatments can be straightforward if it is a simple case of fleas causing a hot spot. Then we would treat the fleas (remove our underlying cause), clean the lesion itself, and treat for infection.

We may also start medications that help decrease the need to itch and traumatize the area. This will allow your dog a great deal of comfort while the skin heals from his canine allergic dermatitis.

How do I treat my dog’s dermatitis?

Treatment options we have available:

• Medications – Antibiotics, anti-parasiticides, antifungals, anti-itch drugs
• Medicated Shampoos – Baths can help decrease skin inflammation and remove pesky parasites.
• Immunotherapy – Targeted therapy against allergens is used to desensitize your dog from flea or food allergies. Repeated injections are necessary to expose the dog to these allergens and increase tolerance.
• Avoidance therapy – Trying to minimize exposure to your dogs’ allergens can be effective but very challenging.
• Food Trials – Often allergies are related to the type of food your dog is eating. Your vet may recommend a “novel food trial.” This is essentially an elimination diet and can be helpful in controlling atopic dermatitis in dogs.

How to prevent dermatitis in dogs?

Prevention of Dermatitis is a wildly common topic talked about in veterinary appointments every day. There are wonderful, safe medications available for our dogs that repel and kill fleas and ticks. These medications are also highly effective for treating mites as well. So, with just a simple pill or topical medication, you can easily prevent parasitic dermatitis.

You can also catch a lot by doing routine exams of your dogs’ skin and coat. If you get in the habit of checking daily, you will notice when the first signs of dermatitis occur. You will also catch other things, like foxtails, foreign material, or growths on your dog’s skin or coat. Be sure to check in between the toes as grass awns and foxtails like to hide and migrate.

We have covered a lot of ground here regarding your dog’s skin and hope that you will feel better prepared the next time your dog may develop atopic dermatitis. It’s important to trust your veterinarian and discuss your goals so you can be on the same page.

Treatment plans can be developed for all financial situations and as long as you both understand the limitations you may face, you can be successful and allow your dog to stay comfortable and itch-free.