How to Identify a Skin Disease in my Dog?

Shar pei- perro

Translated by Nick R

Many diseases can affect your dog, and some of them are cutaneous and their similar symptoms are sometimes difficult to diagnose.

If you want to be aware of the conditions that can attack your furry friend and how you can prevent them, read on.

Dog skin and coat 

Let’s first of all talk about the skin and coat of dogs. Just like for us humans, the skin is the largest organ that dogs have.

The skin is made up of 3 layers:

Epidermis: this is the external layer (surface layer).

Dermis: it’s located under the epidermis, therefore, it’s deeper. Here are located the blood vessels, nerve endings, hair follicles, and sebaceous and sweat glands. “It’s responsible for the repair, flexibility, tensile strength and elasticity of the skin” (Dermatology in dogs and cats).

Hypodermis: This is the innermost layer of the skin, composed of fatty tissue. It “preserves the internal heat, stores energy and intervenes in the metabolism of sexual hormones”.

The coat grows from follicles in the dermis; in the case of dogs, there can be up to 15 hairs in a single hair follicle. Its function is generally to protect against external agents. The coat acts as a thermal insulator and protects the canine from injuries.

Likewise, your pet’s coat can help you to know if your dog is in good health or if he may have a disease or problem. Thus, wanting your dog to have a shiny and soft coat is not only an aesthetic issue but also a matter of health.

So if you notice in your dog’s skin or coat any of these signs:

  • Dry and dandruff.
  • Dull.
  • Signs of alopecia (loss of fur).
  • Reddened skin.
  • Itching.
  • Bad smell.
  • Lumps.
  • Sores.

These are warning signs of a possible dog skin problem and you must take your dog to the veterinarian to get effective treatment.

Common Skin Diseases in Dogs

Here I’ll explain some of the common diseases, their symptoms, and how to prevent them so that your furry dog can enjoy excellent skin health.


Also known as dermatophytosis, it is a fungal infection. Ringworm is a zoonotic disease (it can be transmitted between species, including humans) and is highly contagious. The fungi that usually cause this condition are trichophyton mentagrophytes and Microsporum canis.

These fungi feed on keratin, affecting the skin, nails, and coat.

It spreads by contact with an infected object (such as blankets, bedding, or food bowls) or animal. And young or weakened immune system dogs are the most vulnerable.


The symptoms that an infected canine may show are:

  • Alopecia (loss of coat).
  • Scabs.
  • Bad odor.
  • Inflammation.
  • Dry coat.  
  • Excessive licking and scratching that cause injuries.


Apart from a deep cleaning and disinfection treatment, the disease needs to be treated with topical fungicidal medications or remedies to be applied to the canine’s skin. In addition, the veterinarian may prescribe medication or antifungals to kill the infection.


This disease is caused by external parasites: mites. There are different types of scabies, as it can be caused by different types of mites. It’s a zoonosis, so it can be transmitted to various animals, including humans.

It can also be spread by contact with infected animals or with objects such as infected brushes, toys, blankets or food cups.

Some types of scabies are:

Demodectic scabies: Caused by Demodex canis mites, it usually occurs in localized areas of the skin such as the head or ears.

This mite is always present in the skin of canines, but when the canine suffers a defense problem or an immunosuppressive disease, the mite can develop into scabies.

Sarcoptic mange: Caused by the Sarcoptes scabiei var. canis mite. It’s contagious and considered a zoonosis. It causes a lot of itching and wounds on the skin.

Cheyletiellosis scabies: Also known as walking dandruff, it is caused by the Cheyletiella mite. It is considered a zoonosis.

It can be contracted by direct contact with infected objects or animals.


The symptoms that a canine can present if it has mange are:

  • Itching, the dog scratches and bites itself constantly.
  • Sores on the skin due to excessive scratching.
  • Bad odor.
  • Redness and inflammation.
  • Sores.
  • Scabs.
  • Alopecia (loss of fur).
  • Loss of appetite and, therefore, weight loss.


If you think your dog has scabies, it’s recommended that you take him to the veterinarian immediately to make the diagnosis, so they can choose the most appropriate treatment depending on the breed, age, and type of scabies that your canine presents.

Normally an acaricide will be prescribed that can be applied in different ways, it can be a topical product (applied on the skin) or an oral or injectable product. In addition, you can also get shampoos with acaricides to help soothe your furry one’s skin and anti-inflammatories.

However, before giving any medication you must take into account that it must be prescribed by a veterinarian.

Food allergies 

Although these kinds of problems are digestive, they cause reactions in the canine’s skin. This type of allergy is caused by hypersensitivity to foods such as meat, milk, or eggs.


The symptoms that the dog suffering from a food allergy can show are:

  • Itching and reddening of the skin.
  • Sores due to excessive scratching.
  • Rashes.
  • Vomiting.
  • Gases.
  • weight loss
  • Breathing problems.


The allergy cannot be eliminated from our dog, what we must do is avoid the consumption of the food that provokes this reaction.

So the veterinarian will most probably recommend an elimination diet, in which you eliminate products that your dog normally consumes until you find out which food is causing the allergy and after that, create a new diet without that food.

Environmental allergy 

These allergies are usually seasonal, which means that they appear only at certain times of the year, and can be caused by allergens such as dust or pollen. This type of allergy can cause skin reactions in dogs.


The symptoms of an environmental allergy are:

  • Reddening of the skin.
  • Itching.
  • Excessive licking.
  • Scratching or biting.
  • Alopecia (hair loss).
  • Otitis.


As with food allergies, you must identify the cause of your canine’s allergy. For example, if when you take him for a walk in a grassy place he has an allergic reaction, you should avoid such places.

On the other hand, if it is a seasonal allergy, for example, a pollen allergy, then your canine can be treated with allergen immunotherapy so that he gets more tolerance to environmental elements that harm him. In addition, you can avoid, in this case, areas with many flowers in times like spring when flowers are pollinated.


This disease is usually caused by the occurrence of another health condition in the canine, such as scabies, food allergy, parasites, canine atopy, skin cancer, or hypothyroidism.

It may affect the face, torso, and paws of the dog, and in general, it occurs because the sebaceous glands produce more sebum, which causes the appearance of more grease, scales, and bad odor.

This disease is not contagious, but it can be hereditary. Some breeds are more prone to this disease, such as the Cocker Spaniel, the Labrador, the German shepherd or the Golden retriever.

There are 2 types of seborrhea:

Dry seborrhea: it appears in the initial stages of the disease and produces a sort of dandruff on the animal’s scalp.

Oily seborrhea: this one is more advanced and causes dullness in the coat, bad odor and itchy skin, and as in most skin diseases, the canine can cause wounds when scratched.


The symptoms that a canine with seborrhea may have are:

  • Dry skin.
  • Greasy coat.
  • Scaling.
  • Itching.
  • Irritation.
  • Excessive scratching that can cause skin wounds.


You can use anti-seborrheic shampoos to bathe your dog and give him vitamins prescribed by your veterinarian. Alternatively, you can choose a quality food containing fatty acids such as salmon oil, which is very good in cases of seborrhea.

If your canine has inherited the disease, it probably cannot be completely eliminated, but it can be kept under control with analysis and follow-up by the veterinarian.


This is a bacterial infection of the skin. It’s caused by a bacteria of the genus staphylococcus spp. It can affect the canine’s entire body or a localized area.

“Pyoderma literally means the presence of pus in the skin and can be caused by infectious processes, inflammatory and/or neoplastic causes (abnormal growth of cells or tissues, it can also be called a tumor); even some accumulations of neutrophilic exudate (large numbers of neutrophils accumulate and cause tissue destruction) can be called pyodermas.” (Pyoderma canine)

Pyoderma is categorized into:

Surface pyoderma: found on the skin surface and doesn’t go deeper than the follicles.

Superficial pyoderma: here, the infection stays in the superficial layer of the skin, the epidermis.

Deep pyoderma affects the deeper layers such as the dermis.


The symptoms of canine pyoderma are:

  • Itching.
  • Alopecia (loss of the coat).
  • Bad odor.
  • Dry and scaly skin.
  • Scabs and sores.
  • Pus.


The treatment should proceed according to the following steps as described in this article on New developments in the diagnosis and treatment of canine pyoderma:

  • Recognition and classification of the clinical entity.
  • Choice of an effective systemic antibiotic, supported by the use of topical therapy.
  • Determine dosage, frequency, and duration of treatment.
  • Detection of predisposing factors.


Neoplasms or tumors are abnormal masses in the tissue (like lumps under the skin); they can be benign or malignant. When they are malignant and can affect other tissues or organs, we use the term “cancer” to describe them.

They appear normally in dogs over 7 years, since the older they are, the more prone they are to develop some type of cancer. In addition, some breeds of dogs are predisposed to suffer from this pathology, such as the Labrador, the Golden Retriever, the Schnauzer, and the Boxer.


The symptoms that the canine can present are:

  • Lumps under the skin.
  • Wounds.
  • Anorexia.
  • Vomiting.
  • Depression.
  • fever


After the diagnosis, the best treatment will depend on several factors: whether it is a malignant or benign tumor, how developed it is, and where it is located.

Surgical intervention, chemotherapy, hyperthermia (raising the body temperature to destroy cancer cells in the tissues and thus reduce tumors), immunotherapy, cryotherapy, or alternative treatments can be performed.


It’s an infection that appears in the superficial part of the hair follicles. It’s caused by staphylococcus (a type of bacteria) and can be commonly seen in the armpits, abdomen, and groin. It may appear due to other diseases suffered by the canine, like scabies or seborrhea.


Some symptoms of this disease are:

  • Redness
  • Inflammation.
  • Itching.


For treating folliculitis you can get special shampoos. The veterinarian who has made the diagnosis will explain how often you should bathe your canine to get rid of the infection.

Canine acne 

Acne is a cutaneous inflammatory process that we can observe most commonly on the lips and chin area of the canine. Just as in humans (in some cases), acne only lasts for a while and then disappears.

Some breeds that are more likely to suffer from acne because of their short hair type are the Boxer, Great Dane, English Bulldog, and Rottweiler. On the other hand, it can appear between 5 to 8 months of age, it could be said that in the “puberty” of the dog.  


The symptoms of acne are:

  • Pimples (red bumps).
  • Itching and pain.
  • Sores or bleeding from excessive scratching.
  • Pus.


Topical treatments are usually used to treat acne. The area should be cleaned and disinfected with disinfectant products or specific shampoos recommended by your veterinarian. In some cases, daily cleansing is not enough and you will need to get benzoyl peroxide shampoos or gels.

On the other hand, antibiotics will be prescribed to treat this condition in severe cases.

Prevention of skin diseases in dogs 

Although skin diseases can be caused by different pathogens, it’s really important for your canine to have good hygiene to prevent these infections or skin conditions from thriving.

So, you should have a good bathing and brushing routine for your dog, and clean your pet’s objects and accessories, such as his bed, blankets, toys, or food bowls, since fungi, bacteria or parasites can be found in these places.

And, of course, regular visits to the veterinarian to comply with vaccination and deworming will help your canine to have a strong immune system.