Dog skin conditions 101

June 27, 2023 - 5 min read
This article is not intended to be a substitute for professional veterinary advice, diagnosis, or treatment. Always seek the advice of your veterinarian with any questions you may have regarding your pet’s care, treatment, or medical conditions.
scruffy wet dog with brown eyes and tan fur looks directly at camera with suds on top of head

The skin is the largest organ in a dog’s body, and it constantly interacts with the external environment. It shouldn’t be too surprising that skin conditions routinely land at the top of lists of the most common health problems in dogs.

Having a basic understanding of dog skin conditions can help pet parents recognize when a problem is developing. This comprehensive guide is full of practical advice and explanations to help you manage the most common skin conditions that affect dogs.

Common Causes and Symptoms of Skin Conditions in Dogs

Skin problems can arise because something has gone wrong within a dog’s own body, because something in the dog’s environment is having an adverse effect, or due to a combination of internal and external factors. Common causes of skin conditions in dogs include: 

  • allergic reactions

  • parasites

  • bacterial, fungal, or viral infections

  • hormonal imbalances like Cushing’s Disease or hypothyroidism

  • immune-mediated diseases like Discoid Lupus Erythematosus

  • cancers

  • trauma

  • developmental or genetic disorders

  • nutritional deficiencies

  • exposure to toxins or irritants

body of a dog with hair thinning and loss

That’s a long list! And to make matters worse, the skin tends to react to many different health problems in the same way. Almost every skin condition in dogs will lead to some combination of the following symptoms:

  • hair loss

  • itching or discomfort

  • redness

  • various types of skin lesions such as pustules, erosions, ulcers, masses, hot spots, and seborrhea (flakiness)

Therefore, trying to diagnose and manage skin problems in dogs at home will often result in trying a treatment that either doesn’t work or maybe even makes things worse. If your dog has persistent symptoms of a skin problem, make an appointment with your veterinarian. They will need to examine your dog and possibly run some diagnostic tests too.

The Importance of Veterinary Diagnosis for Dog Skin Conditions

Unless the problem is obvious (a horrible flea infestation, for example), your veterinarian will probably not be able to tell you exactly what is going on simply by looking at your dog’s skin. But they will thoroughly examine your dog’s whole body and use what they find to help them pick what diagnostic tests are most likely to provide them with the most information. Oftentimes, the first tests they will run are:

  • skin scrapings to look for mites that cause mange

  • skin cytology to look for bacterial and yeast infections

  • fungal culture to rule out ringworm 

If the veterinarian suspects that a “whole body” health problem is causing your dog’s skin symptoms, they may also want to run:

  • blood work

  • urinalysis

  • fecal examinations

  • tests to look for specific health problems like Cushing’s Disease or hypothyroidism

But sometimes a physical exam and basic lab work will not provide an answer. At this point, the veterinarian may recommend more complicated or advanced testing, such as:

  • intradermal skin testing for environmental allergies

  • trial with an elimination diet to rule out food allergies

  • skin biopsies

Your veterinarian may not initially recommend pursuing a full diagnostic work-up for your dog’s skin condition. When a problem is new and not too severe, or if it could be a flare-up of a previously diagnosed condition, they may want to try some treatment first. If it doesn’t work as well as expected, more diagnostic testing will be necessary.

 Now, let’s look at some skin conditions that many pet parents have to deal with at one time or another.

A veterinarian is examining a dog with dermatitis with a magnifying glass. Vet examining dog with bad yeast and fungal infection on skin and body

1. Allergies and Dermatitis in Dogs

Dermatitis is simply a word that means inflamed skin, which usually leads to redness, itching, and hair loss. Dermatitis can be caused by many different skin conditions in dogs, including allergies. The most common allergic triggers for dogs are:

  • environmental allergens like pollen, mold, and house mites

  • ingredients in food

  • flea bites

Genetics often plays a role in dog allergies. The word “atopy” describes the underlying genetic tendency to have allergic reactions to environmental triggers. The resulting condition can be called atopic dermatitis or allergic skin disease. Food allergies are less common in dogs, but they can also cause dermatitis. Finally, most dogs will get a little itchy if they are bitten by fleas, but dogs with a flea allergy can develop a horrible case of dermatitis after just one flea bite.

Tick and flea prevention for a dog stock

Treatment for atopic dermatitis frequently involves combination therapy, including:

  • medications and nutritional supplements to reduce itching and the allergic response

  • reducing exposure to allergens (frequent baths to remove pollen from the coat, for example)

  • immunotherapy (allergy shots or drops)

Food allergies are managed by feeding a dog a diet that does not contain their specific triggers (beef or dairy products, for example), while dogs with flea allergies need to be on an effective flea preventative all year.

These types of allergies are chronic conditions that require long-term management, and occasional flare-ups can still occur. 

2. Parasites and Skin Infestations

Fleas aren’t the only type of parasite that causes skin problems in dogs. Ticks, lice, sarcoptic mange mites, and demodectic mange mites can all be to blame too.

Fleas, ticks, and lice can all be seen with the naked eye, but sarcoptic and demodectic mange mites are so small that they are best identified by using a microscope to look at samples collected from skin scrapings.

Many of the products commonly used to treat and prevent flea and tick infestations are also effective against sarcoptic mange mites, demodectic mange mites, and lice. Your veterinarian can recommend a product that will be safe and effective for your dog.

3. Bacterial and Fungal Infections

Bacterial and fungal (yeast or ringworm) skin infections are another common cause of dermatitis in dogs. The first time a dog gets a skin infection, veterinarians will usually simply treat it with appropriate antibacterial or antifungal medications. In mild cases, this may involve topical treatments like medicated shampoos, sprays, and ointments. More severe cases may also require oral antibiotics or antifungal medications.

On the other hand, chronic or recurring bacterial and fungal infections usually occur because of an underlying health problem like allergies, hypothyroidism, or Cushing’s Disease. If the primary problem isn’t diagnosed and treated, the dog’s skin infection will keep coming back.

Managing Your Dog's Chronic Skin Conditions

Some skin conditions are one-time problems. For example, if your puppy develops ringworm, it should go away and stay away if it is treated appropriately because, as dogs mature, they develop good natural immunity to ringworm.

However, many other skin problems in dogs are chronic conditions that require long-term management. Examples include allergies, autoimmune diseases, and hormonal disorders. Treatment should first be aimed at the underlying problem, but if skin symptoms continue, they may need to be addressed directly as well. Options may include frequent bathing using a medicated shampoo, dietary supplements (omega-3 fatty acids, for example), a change in diet, and medications to reduce itching or inflammation.

Veterinarian holding a jack russell terrier dog with dermatitis

Staying in touch with your veterinarian is essential whenever you are dealing with a chronic health problem. Go to all of your dog’s scheduled rechecks and call your vet for advice at the first sign that their symptoms are getting worse.

Supporting Your Dog's Skin Health

Healthy skin is naturally resistant to many potential problems. To keep your dog’s skin in the best possible condition,

  • Feed a nutritious, balanced diet

  • Ask your vet about a dietary supplement that includes omega-3 fatty acids

  • Provide fresh, clean water

  • Keep your dog at a healthy weight

  • Groom your dog as needed based on their coat type

  • Protect your dog from extreme heat and cold

  • Dry your dog off if they become wet

  • Thoroughly examine your dog’s coat and skin at least every month

Talk to your veterinarian if you notice any changes in your dog’s coat or skin. Diagnosing and treating problems early is almost always more effective and less expensive than waiting until their symptoms have gotten worse.

How Dog Insurance and Wellness Can Help With Your Dog's Skin Conditions

Because they are so common, it’s not really a matter of “if” but rather “when” pet parents will have to deal with a skin condition that affects their dog. 

Dog insurance is a great way to help manage the costs associated with diagnosis and treatment, but it’s best to purchase a policy early in your dog’s life. If symptoms of a chronic skin problem become evident prior to insurance coverage, the condition will be pre-existing and likely ineligible for coverage.

If you’re interested in prevention, an optional (non-insurance)Wellness Plan can even pay for parasite preventives, dietary supplements, shampoos, and other treatments that will help you keep your dog’s skin and coat in great condition.


Jennifer Coates, DVM
Veterinarian, Veterinary Writer, Editor, and Consultant

Dr. Jennifer Coates is a writer, editor, and consultant with experience in veterinary medicine, science, animal welfare, conservation, and communications. She has written for outlets including petMD, Chewy, and ManyPets.