Guide To Canine Skin Diseases and Conditions


"There is a long list of canine skin diseases and conditions that need to be considered before diagnosing the actual problem (see below for pictures and descriptions). If your dog is suffering from mild discomfort, then home treatment such as medicated shampoo therapy to eliminate itch and scratching is worth a try along with home remedies to boost immune system and manage the skin problem.

If dog skin itch or scratching causes redness, hair loss (alopecia), matting of hair or an interruption of your dog's normal routine, such as stopping in the middle of play to chew on the skin, then it's smart to visit a veterinarian for a definitive diagnosis and prescription medication. Puppies should always be diagnosed by a veterinarian since a dull coat and hair might indicate a case of dog worms.

Demodicosis mange is also seen in puppies just after being born. For adult dogs, diagnosis of dog skin diseases are based on the appearance of the skin and if any other symptoms exist. Flea allergy is the leading cause of problems, and is often present even when there are no signs of fleas in the home. Similarly, lice infestation can cause matting of hair, small wounds since there are two types of lice, i.e., chewing and blood-sucking lice.

Mild skin allergy is caused by contact, ingestion, injection or inhalation of an allergen. Symptoms include itch, rash or hives. In very rare cases a dog is hypersensitive, resulting in a reaction that could progress to anaphylactic shock (heart collapse and/or trouble breathing). These more acute cases are rare. Mild allergy is treated with one time or multiple doses of the prescription medication Diphenhydramine. Studies now show that the addition of a steroid is not necessary(16), however see your Vet for a specific diagnosis and treatment recommendation."

dog skin problems picturesDog Skin Problem Picture
Dog Skin Allergy

Source: WSU Veterinary School

Start Here: How to Diagnose Dog Skin Problems

A veterinarian will attempt to narrow the list of possible causes by taking a thorough history along with a physical exam and some diagnostic lab tests. Dog flea allergy is the leading cause of skin problems, followed by other types of allergies such as environmental dog allergies (atopy) and dog food allergy.

Mange, a parasitic condition that causes patches of baldness, is the next leading cause and is primarily evident in puppies.

Other symptoms which accompany dog skin problems such as severe hair loss and excessive panting could indicate an underlying disorder such as an endocrine disease such as hyperadrenocorticism or Cushing's Disease. Treatment for dog skin conditions involve keeping the skin clean and treating the underlying as well as secondary cause such as bacterial infection or parasites.

Primary vs. Secondary Canine Skin Problems

Your vet will try and determine if  a dog skin problem is primary or secondary. Primary skin lesions are caused by a specific disease. Secondary dog skin issues occur when a disease progresses or from a self-injury such as itching or scratching as is common with dog skin allergy. Secondary dog skin problems can also be a result of bacterial infections.

Identifying canine skin diseases and conditions can be difficult since there are many causes. The key to understanding which condition your dog is suffering from is to do your best to match the characteristics of each cause with the symptoms exhibited by your dog.

Canine Skin ProblemsDog Skin Problems Photos (top left to right): Alopecia due to follicular dysplasia, Castration-responsive dermatosis, Pattern alopecia on ear, Color dilution alopecia.

Symptoms and Causes of Dog Skin Diseases

Canine skin conditions vary based on shape of the lesions and condition of the skin such as crusts, scars, ulcers, or scales, and the dogs behavior such as itching.  It also depends on the location of these lesions or symptoms on body. The following table describes common symptoms and causes.


 Possible Cause

Abnormally colored skin (macules)

Macules are circular flat areas up to 1 cm in diameter. 

  • Red skin bumps (erythematous macules) are caused by the bacteria staphylococcal pyoderma and flea bite hypersensitivity.  They can also be caused by fly bites.
  • Haemorrhagic macules (bluish skin discoloration) caused by coagulopathies (blood coagulation disorder) and vasculitis (blood vessel inflammation).
  • Hyperpigmented macules: Black skin spots caused by the bacteria staphylococcal pyoderma. Found on the scrotum, anus along with testicular tumors, prepuce (canine foreskin).

Alopecia (hair loss): occurs in four patterns -

  1. Focal - small single patch
  2. Multi-focal - several small circular patches. Looks moth-eaten.
  3. Regional - alopecia that occurs in one region of the body such as a single leg
  4. Symmetrical - hair loss on both sides of the body, equally distributed

Other terms include:

  • Hypotrichosis - means that a dog has less than a normal amount of hair or simply, thin hair
  • Defluxion - sudden hair loss
  • Easy epilation - when hair is removed with little resistance such as when a dog sheds

 Most conditions that involve canine hair loss that occurs spontaneously (spontaneous alopecia) are primarily caused by a hormonal disturbance (malfunction of endocrine system) such as hypothyroidism.  Other causes are folliculitis which is causes by inflammation of the hair follicle due to canine ringworm or a bacterial infection.  Often, a cause cannot be determined.

In puppies it can be caused by a hereditary or congenital defect, parasites, bacterial (impetigo), fungal infection (dermatophytosis - also called ringworm) or in older dogs canine sterile granulomatous dermatitis or lymphadenitis.

Patchy hair loss on the head and face is a symptom of mange. Patches of dog hair loss can also indicate ringworm or allergy.

The secondary cause of dog hair loss is when the dog bites, rubs, scratches, chews or is groomed excessively.

Black Skin, Black Crusty Skin and Hperpigmentation

Dog Skin Problem - Picture of HyperadrenocorticismDog Skin Problems Due to Pituatary Dependent Hyperadrenocorticism

Hyperpigmentation occurs when the skin has too much of pigmentation, resulting in black dog skin spots.  Causes of dog black skin spots include:

  • allergy
  • Malassezia dermatitis (yeast infection)
  • Endocrine disorders

If the black skin spots become black scabs on dog or crusts, it is a symptom of a condition call Alopecia X or Cushing's Disease which is a problem associated with adrenal glands producing certain hormones in excessive quantities. Cushing's disease is also called Hyperadrenocorticism.


 Possible Cause

Dry, oily or flaky skin due to canine Dandruff or Seborrhea

Seborrhea refers to scaling skin which occurs when skin particles accumulate on the outer layer of the skin.  Dog seborrhea sicca refers to dog dandruff, while greasy or oily skin is referred to as seborrhea oleosa.  Canine seborrhea is caused by allergy, hormonal problems, bacterial infections, fungus, and tumors. Seborrhea can also cause scars, bumps and pimples on the skin.

Dry, Dull Coat

A dry, dull-looking coat along with severe hair loss, excessive panting, a distended abdomen, a reduction of muscle mass and thin/frail skin can indicate some type of underlying disease such as hyperadrenocorticism (Cushing's Disease) .  Be sure to mention changes in coat condition as this is an indicator of something going on in your dog's body.  It can also be a sign of poor nutrition. 

Foot and Nail Problems

Dog foot and nail problems are a challenge to treat. They are classified into 4 groups:

  1. Footpad issues: if mostly on the footpads, it could be Pemphigus, an autoimmune disease that causes lesions or pustules. In this condition immune system mistakenly attacks top layer of skin i.e., epidermis and thus causes lesions or pustules; which appears as small, pus-filled, blister like sores. Lab testing of a skin biopsy is needed for a diagnosis. For dry foot pads, a dog's feet are supposed to be dry and possibly cracked. Foot pads are treated when a dog is in pain. Other times avoid lotions or ointments that might be licked off.
  2. Toes: Issues between the toes is frequently caused by fungal infections, which over time paves way for bacterial infections as well. These bacterial infections are either termed as foliculitis (inflammation of hair follicles) or furunculosis (a penetrating and perforating follicular inflammation). In many cases the condition starts as a fluid-filled nodule between the dog toes. the nodule ruptures, forming a furuncle in the toe area. Treatment involves the use of oral as well as localised antibiotics for as long as 6 to 12 weeks along with hygiene management.
  3. Nail bed problems: often caused by bacterial paronychia resulting in malformed or broken nails. Treatment involves removal of the diseased nails.
  4. Foot itch (Pedal puritus, Malassezia dermatitis) is typically caused by the yeast Malassezia. The condition is usually seen on all 4 feet. The condition can cause the dog to injure itself when reacting to the condition. Treatment involves the use of Ketoconazole (an anti-fungal) orally 1x a day for 5 to 10 days; however relapse is common. It can also occur in combination with atopic dermatitis (seasonal allergy).

Hot Spots (acute moist dermatitis)

Caused by the removal of a superficial layer of skin due to scratching or biting. The condition is characterized by extreme discomfort, thus excessive itchiness or pruritis. 

Video: Dog Hot Spots
Video review of the causes and treatment of a dog hot spots. These types of dog skin problems are caused by self trauma, allergic reaction, fleas, grasses, pollens or even an insect bite. Treatment starts by cleaning any sores on the dog with soap and water. Then apply an antibiotic ointment and cortisone ointment. If the condition worsens see a veterinarian to learn more about the condition.


 Possible Cause

Itching and Scratching, No Other Symptoms

If the skin condition is limited to dog skin itch and scratching, then the first step is to suspect the beginning of a flea infestation.  It's easy to miss fleas when inspecting your dog's hair, so don't be surprised if this is the cause.

If fleas are not found after combing your dog with a flea comb, consider allergy as a possible cause. For mild conditions, ask your vet about using an antihistamine (for example diphenhydramine). You can also bring your dog some relief with a dog colloidal oatmeal shampoo.  Avoid any product that is medicated at first, since these may cause additional irritation.

Other possible causes after fleas are ruled out are environmental allergies (called atopy), food allergy and demodectic dog mange. Mange is caused by mites and is usually seen in puppies. Symptoms include bald patches and is diagnosed by a skin scraping in the Vet's office.

Rash (Erythema)

When a dog's skin has a rash or is red in color and is comprised of pustules (small, pus-filled blister like sores on skin), papules (small, red circular dog skin pimples less than 1 cm in diameter) and macules (discoloured skin spots), it implies that the problem is either of following conditions, thus requires detailed examination and even lab-testing before a conclusive diagnosis. However, use of natural remedies can help relieving the symptoms:

  • an allergy
  • a parasite infestation
  • an infection
  • an immune-mediated skin diseases

Itch, Redness and Pus

In general, if your dog is suffering from skin itch, and if skin lesions are red in color and oozing pus, and are accompanied by hair loss, a trip to the veterinarian is needed as the condition is probably beyond your ability to control the problem with over the counter medications. In this case a dog skin infection has probably taken hold, requiring antibiotics and possibly short term steroid use for inflammation.

Acne and Dog Pimples

Dog pimples or acne can have multiple causes including but not limited to skin tumors, allergy, infection (fungal, bacterial), fleas and mites. Some dogs can get acne with pimples around the mouth and chin. Use a dab of human benzoyl peroxide to see if the condition gets better.

Dog skin pimples (papules less than 1 cm in diameter)  are typically caused by:


Possible Cause

Red spots on dog skin with a central yellow sac of pus (pustules)

Pustules are most commonly seen with a bacterial skin infection. Causes include:

  • Staphylococcal pyoderma
  • Demodicosis (mange)
  • Pemphigus (an autoimmune disease resulting in damage to top-layer of skin called epidermis and mucus membranes)

Cysts or Lumps On or Under Dog Skin or on Neck

If you see a dog skin lump do not automatically assume that is skin cancer. There are many "benign" causes of lumps or bumps such as a non-cancerous cyst, insect bite, an abscess or a benign lipoma (fat accumulated under the skin.)

Some of potential signs of dog skin cancer include:

  • Sudden appearance of a lump on skin
  • Changes in the size of lump or bumps over time
  • Changes in your dog's behavior
  • Changes in your dog's health condition such as symptoms of lethargy and appetite loss
  • Lesions that do not heal
  • The appearance of other medical issues (e.g., in urination, breathing etc.) that coincide with one or more skin changes

Dog skin tags can look like a tumor, but usually are benign and will not cause any harm. The tag itself differs from a wart is that they are connected to the skin with a thin base. They are often similar in color to the skin and can sometimes be moved a bit with the fingers. In most cases dog skin tags can be left alone unless there is a cosmetic reason or the size of it becomes problem and requires removal. Another reason for removal is when you have a dog that licks or scratches the area, allowing irritation and infection to take hold.

Pemphigus (skin pustles and crusts)

This is an immune system disorder where the dog's body (immune system) mistakenly attacks the substance that holds skin cells together. The result is the skin literally coming apart, resulting in skin pustules and crusts, particularly around the bridge of the nose and feet.  Symptoms include painful skin that is very red and crusty in appearance.  Commonly effected areas of immune mediated dog skin diseases are at the ear margins, lips and nasal area.  Canine lupus is another immune system related disorder with similar symptoms.

Bad Skin Odor and Smell

There are many possible causes for dog skin odor. If the problems only occur during one time of year, then seasonal allergies are probably the cause. Bacterial and fungal Infections such as yeast can also trigger a smell, with the problem being corrected after treatment with a medicated shampoo (you can try this first) and antibiotics if needed. Other potential issues include seborrhea (condition that affects scalp and causes scaly patches and inflammed skin along with severe dandruff) which also can be addressed with a shampoo. If shampoos for infection or for seborrhea not work, then visit a veterinarian for a combination of topical and antibiotic treatment.

Scratching, Licking the Skin and Dog Skin Itch

Dogs that scratch the face, feet ,ears and arm pits usually have some form of inhalant allergy. Dog flea allergy causes dogs to scratch or lick the tail, back, groin and thigh.

Canine skin rash or red patches on the skin

Red, irritated looking skin is a non-specific symptom and can be associated with any number of disorders such as mange or immune-mediated disorders (lupus, pemphigus)

juvenile puppy pyoderma on faceJuvenile Pyoderma, a Puppy Skin Disorder Causes Pimples on the Face
Photo Credit: Washington State University


Possible Cause

Scabs or Crusts

Dog skin crusts or dog skin condition scabs are caused by the build up of pus or skin scaling due to skin diseases such as the immune-mediated disease canine pyoderma (pus filled bumps caused by bacterial infection).  Crusts on the ear margins can be caused by mange.

In Juvenile Pyoderma in puppies the sores form on the top of the muzzle and spread to the rest of the face.

Scratches on Rear End

Scratching near the tail could be caused by dog scooting on the ground due to a full anal gland.

Skin Sores

Parasites (fleas, mites, lice), poor grooming, dog skin infection (bacterial pyoderma, fungal), endocrine diseases, skin or hair follicle disorders disorders such as seborrhea, medication side effects (from corticosteroids) and allergy. It is rare for a sore or lesion to appear without another underlying condition such as allergy.

Skin Scaling (dog skin dandruff)

When the outside layer of the skin is shed, it is usually not seen on the skin and coat. Some conditions cause the flakes to accumulate. 

Seborrhohea is a condition that refers to scaling and dry skin along with stub-born dandruff. On the other hand, if the skin is very greasy it is called seborrhoea oleosa.

Hyperkeratosis is a condition where the skin thickens, usually on the nose or the footpads.


Possible Cause

Thick Dog Skin

If you see a change in dog skin thickness, it can be caused by thickening of the skin or inflammation. Causes of dog skin thickness include:

  • Lichenification: This makes the skin look like elephant skin. It occurs when a dog has a disease that causes chronic itch. It is an attempt by the skin to protect itself.
  • Callus: thick skin area that forms over a pressure point.

Thinning Dog Skin (cutaneous atrophy)

Dog skin that is thinning can be due to hyperadrenocorticism or Cushing's disease. Skin that suffers from cutaneous atrophy is easily wrinkled and is less elastic.  It can also occur in dogs where glucocorticoids are applied as an injection or cream.

Warts (Canine papillomatosis)

Warts (papillomavirus) are non-cancerous - benign contagious dog skin pumps. They are transmitted via indirect and direct contact. Warts start as small papules and become larger to become small, cauliflower warts. They are found on the conjnctivae (eyes), buccal mucosa (lining of the cheeks and mouth), gums, tongue and lips.

The most common type are oral warts that form in the oral cavity. Warts in other places are dark, slightly raised papules and plaques. They rarely become cancerous.(9)

dog skin sores pyodermaDog Skin Bumps - Pictured: Dog Sores on German Shepard from Deep Pyoderma
Source: Washington State University, Dr. Candace Sousa, Veterinary Specialist

Common Causes of Canine Skin Disease

Flea allergy dermatitis, environmental and food allergies are the leading causes of to dog skin lesions and rashes. Even if you don't find any fleas on your dog, they are skilled at hiding, with even a few able to cause a problem in allergic dogs. Symptoms are usually in the form of raised red bumps known as hives. They are itchy and will cause your dog to scratch. Excessive scratching may break the skin, leading to infection.

If no infection occurs, hives will usually go away on their own once exposure to the allergen is removed. If infection develops, however, medical treatment will be needed. See your vet if your dog has sores that don’t go away in a few days, or sores that ooze anything yellowish in color. He may need antibiotics.


Allergy is a common cause of canine skin disease. The skin is the largest organ in the dog's body and is exposed to environmental influences such as allergens. Types of dog skin allergy include:

Lhasa Apso with Atopic DermatitisLhasa Apso with Atopic Dermatitis

Atopic Dermatitis

Atopic dermatitis is a reaction to airborne allergens such as powder mites, weeks and tree pollen. It is not clear why the reaction occurs, although it is believed that there is some genetic predisposition among certain breeds(2):

  • American Staffordshire Terrier
  • Boston Terrier
  • Boxer
  • Bull Terrier
  • Cairn Terrier
  • Dalmatian
  • English Bulldog
  • German Shepherd
  • Fox Terrier
  • French Bulldog
  • Golden Retriever
  • Shar Pei
  • Shih Tzu
  • West Highland White Terrier

Triggers include air pollution, excess hygiene or stress. Allergens enter the body by swallowing, skin contact and by breathing them in.

Symptoms of atopic dermatitis are skin redness (erythema) and itch (puritus) and are usually on the abdomen, feet and face. Scratching can cause additional dog skin problems such as infection.

Treatment of atopic dermatitis skin problems on dogs starts with bathing since it helps to remove any surface allergens. The selection of shampoo should be based on what you are trying to achieve:

  • Bacterial or Fungal Infection: Medicated shampoo can address infection or fungal overgrowth.
  • Anti-itch: For itchy dogs, consider an anti-itch formulation that contains calming elements such as oatmeal or essential fatty acids such as All Natural Anti-Itch Shampoo.
  • Anti-seborrheic shampoo: For dogs that have scaling or seborrhea (dandruff) in addition to the dermatitis. Look for a shampoo such as Duoxo with ingredients such as zinc salts, selenium disulphide, salicylic acid, sulfur or coal tar.

The veterinarian might also recommend a hypoallergenic diet that is formulated for skin and coat health. New products have been introduced that help to improve the skin layer. This includes:

  • Phytosphingosin: Helps to improve the lipid composition of the skin. Found in Duoxo spray.
  • Topical Essential Fatty Acids: An essential fatty acid spray can help to improve skin barrier function, reduce water loss and improve the hydro-lipidic composition of the skin.
dog skin allergies picturesDog Skin Allergies: Atopic Dermatitis on Abdomen and Legs

Food Allergy Dermatitis

Food allergy in dogs causes itching on the ears and skin a few minutes, hours or even weeks (usually 24 to 72 hours)(3) after consuming an allergen. Food allergy may also make a dog susceptible to bacterial skin infection. The condition can be accompanied by nausea, increased number of bowel movements, diarrhea or vomiting.

Ingredients that commonly cause food allergy in dogs includes:

  • beef
  • chicken
  • corn
  • soy
  • wheat
  • dairy

The condition is diagnosed by providing a hypoallergenic diet or elimination diet (diet of just the basics) and then seeing improvement.

Avoid treats when on this diet as they are often the cause or a cause of the dog skin problem.

Flea Allergy Dermatitis (FAD)

Flea allergy is a condition that pet parents tend to deny, even when the veterinarian makes that the diagnosis. Reasons for dogs getting fleas include:

  • Dogs that come in contact with untreated animals.
  • Lack of consistent treatment.
  • Substitution of less effective and cheaper store bought spot-ons instead of prescription grade products.(10)

Symptoms of flea allergy dermatitis include:

  • Itch and scratching on the back half of the dog.
  • Crusted skin bumps (papules) in the umbilical fold
  • Skin lesions (crusted papule) that have a long duration
  • Symptoms in the classic areas of the body; dog has scabs on back near tail base, lower back, rear part of the dog and inner thighs.
  • Itchy skin nodules

Treatment for flea hypersensitivity involves the use of prescription products that disrupt the flea lifecycle and that kill adult fleas. Goals are to kill any existing fleas and the continued prevention of fleas through the use of spot-ons, collars and oral products.  New spot-on prescription products are applied to the skin every 3 to 4 weeks and are highly effective. We do not believe that over-the-counter products from pet stores provide the same level of residual activity or safety.

Dog Mange

There are two types of dog skin conditions referred to as mange, demodectic and sarcoptic. It is caused by mites, which are generally microscopic and burrows in skin.

Demodectic Mange

Demodectic dog mange is usually mold and heals on its own in 6 to 8 weeks. It could last months in localized areas on the body.(6) Studies show little difference between treated and untreated dogs for small infections that are in one area of the body. For small localized cases, therapies include using benzoyl peroxide or mupirocin massaged into the skin.  

Localized cases (limited areas on the body) could cause small red hairless spots. Other symptoms can include pimples, thick skin and pus, scaling around the eyes, mouth and front legs.

For generalized cases that are all over the body the medication Amitraz, which is a monoaminooxidase inhibitor, is prescribed.  It is a topical that is applied every 2 weeks.

90% of cases can be cured, but can take up to 12 months. To ensure progress is being made a veterinarian may request repeat office visits very month. Many dogs with demodectic mange also get a bacterial skin infection. For this reason an antibacterial shampoo can help to address any skin crusts.

Sarcoptic Mange

Sarcoptic dog mange (scabies)  in dogs is caused by mites. Symptoms include extreme itch, papules, scales and crusts. 

The condition is diagnosed by a skin scraping, although this form of diagnosis is only positive in 30% to 50% of dogs with the condition.(7)

Treatment is with parasiticidal drugs that are administered every 2 to 3 weeks such as as a Selamectin spot-on. Other medications are ivervectin or milbemycin ,but these cannot be used in Old English Sheep dogs or Collies.

Bacterial Skin Infections

dog skin infection picturesDog Skin Infection Pictures (top: left to right): Deep pyoderma of the hair follicles - folliculitis, Superficial pyoderma on abdomen, Epidermal Collarette, Short-coated pyoderma

Dog bacterial skin infections are commonly referred to as:

  • furuncolosis (penetrating or perforating follicular inflammation)
  • folliculitis (superficial pyoderma)
  •  pyoderma (bacterial infection)

The infections are usually caused by the cover colonization of the skin by Staphyloccoccus. The bacteria is found on normal dog skin, but causes a problem when it grows beyond normal levels, frequently when another condition is suppressing the immune system.

 This can be triggered by:

  • Allergies
  • Parasites
  • Hormonal imbalance
  • Kertatnization disorder
  • Immunodeficiencies
  • Metabolic disorders

Symptoms of a bacterial infection include:

  • Rash
  • Skin bumps
  • Pustules (whiteheads)
  • Comedones (blackheads)

Bacterial skin infections can look like Demodectic mange and Malassezia. For this reason, conditions like these need to be ruled out of a Veterinarian before reaching a definitive diagnosis.

dog skin rash picturesDog Skin Rash Pictures (left to right): Melassezia (yeast infection) on face and ear.

Certain breeds such as Standard Poodles, Vizslas, Akitas and Samoyeds suffer from deep pyoderma or infection as a result of the condition sebaceous adenitis. Deep infections can also be helped by antibacterial benzoyl peroxide shampoo. The shampoo works by decreasing bacteria on the skin surface and by reducing the likelihood that an infection will return. Shampoos are used 2x per week.

All dogs suffering from skin infection will need to be re-evaluated for progress.


Folliculitis is a bacterial skin infection and inflammation that causes mild to more severe skin itch. In most cases allergy is the underlying cause. Antibiotic therapy is frequently used to resolve the problem for a period of three weeks using a combination of oral and topical medications.  If the condition is mild, a antibacterial shampoo or spray could be of help.


Deep pyoderma refers to cases where there is a more severe skin infection. Most cases involve hair follicles that are infected with Staphylococcal infection. Symptoms include inflammation and redness. The condition is treated for 4 to 8 weeks with antibiotics.  A form of deep pyoderma that affects the skin between dog toes is called Pododermatitis. Oral antibiotics are used to treat Pododermatitis.

Dog Ringworm Skin Condition on Nose of 9 Year Old Miniature Pinscher
Source: Washington State University


Calluses (thickened skin) form when a dog consistently lies on hard surfaces. The friction between the hard surface and the skin causes thickening to occur. The most common location is a dog elbow callus, but it could also form in other areas of the body.

Treatment involves replacement of the hard surface with a softer dog bed or blanket. You can use a soothing balm or butter, but do not do this unless you also solve the problem, which is replacing the hard surface with a softer one.

Fungal Skin Infections

Dog fungal infections are also called ringworm or Dermatophytosis. Typical symptoms are hair loss, crusting and scaling in a classic circular pattern. It is less common to see symptoms such as pain, itch or skin inflammation.(8)

It is common to see a dog fungal skin infection on the forelegs (can cause spots on the feet) and face since these come into contact with the environment.

The fungus can invade hair follicles, causing hair loss or feed on the keratin in the skin itself. Dogs with a compromised immune system are at greater risk of fungal infection.

The dog skin problem is diagnosed by examining the skin under a Wood's lamp or a fungal skin culture. Treatment involves the use of topicals (azoles) that contain Ketoconazole, Itraconazole, Fluconazole or other approved medications. A veterinarian might also recommend a medicated shampoo or the use of a Lime-suflur dip used 2x per week.

All items in a household with a fungal infection patient should be cleaned thoroughly.

Dog Skin Ulcers

A dog skin ulcer is a type of wound where there is a breach in skin continuity and it doesn't heal at it's own. Since dogs have relatively thin skin, diseases that damage the skin or self-trauma results in an ulcer.(15)

Dog Skin UlcersDog Skin Ulcer Photos Caused by a Decubitus ulcer. These ulcers form over bony prominences.(1)

There are several potential causes of skin ulcers in dogs. These skin problems in dogs include:

  • Histoplasmosis: fungal infections characterized by ulceration and skin lesions.
  • Leishmaniasis: nose ulcers 
  • Lymphoma: cancerous bumps
  • Melanoma: dark lesions on older dogs
  • Panniculitis: caused by skin injury or an autoimmune disorder
  • Phaeohyphomycosis: contaminated wound
  • Pyoderma: bacterial skin infection
  • Pythosis: skin sores on legs
  • Sebaceous Gland Tumors: tumors that form on the skin
  • Spider bites: skin swelling after bite
Canine Squamous Cell CarcinomaSore on Dog Back Caused by a Squamous Cell Carcinoma (SCC), a condition related to sun exposure on the back.

Diagnosis of Canine Skin (Integumentary) Problems

Your vet will examine your dog's skin carefully as part of a complete examination. The exam will start with a thorough history since many dog skin disorders are more common in certain breeds and at specific ages. There is also a higher incidence of specific types of dog skin problems in some breeds.

In order to properly diagnose diseases and conditions canine skin, various tests may be needed along with physical examination. Tests might include:

  • Examining skin under a special light (a woods light): this is done to check for certain fungal infections such as ringworm.
  • Dog skin biopsy: in this test, a needle is used to remove cells from a lump to be examined by a pathologist. This can determine if a lump is cancerous or if it is just a cyst or wart.
  • Blood tests: might be done to check for infections and certain nutrient deficiencies.

If you keep your dog clean and it continues to smell or have a greasy coat then your pet is probably suffering from parasites, seborrhea or a skin infection.

Dog Skin Problems by Age

Diseases and Conditions Canine Skin By Age

Dog Age Common cause of Dog Skin Disorders
Under 6 months Dog Mange (Demodicosis)
Canine Acne
Juvenile Pyoderma (puss filled dog skin lumps)
Ringworm (dermatophytosis)
Middle age dogs and young adults Dog skin allergy
Hormonal imbalance
Canine seborrhea (oily coat, crusts and scabs)
Older Senior Dogs Hair loss (alopecia)
Dog Skin Tumors (neoplasms, cancer)

Dog Skin Conditions by Body Location

Diseases and Conditions Canine Skin by Body Location and Symptoms

Location on Dog Body Affected and Symptoms

Dog Skin Disease that could be causing the problem and related treatment options

Papules on the Small of the back, middle of the back thighs, groin, belly, tail base

dog flea bite hypersensitivityDog Flea Bite Hypersensitivity By:
dog flea allergyDog Flea Allergy PictureBy:

Flea bite hypersensitivity which is treated for itch and flea prevention. Kill fleas with a product such as a Herbal Flea Dip.

Skin redness, hair loss, papules, skin crusts, all over body or in one area

dog bacterial skin infectionDog Bacterial Skin Infection PictureBy:

Dog Skin Infection (try anti-bacterial dog shampoo therapy), antibiotics

Localized Demodicosis (dog mange) Skin redness, hair loss and skin scaling on the dog face in less than 4 spots.
Generalized Demodicosis: Hair loss, skin crusts, papules, pustules in more than 5 areas.  Hair loss on paws.

dog mangeMange on DogBy:

Condition is caused by mites and is commonly referred to as dog mange. If in one area, may heal on tis own. For generalized mange consider a lime-sulfur dip such as Naturasil.

Skin papule (raised area) on the ears, elbows, abdomen

Sarcoptes mange or scabies using a lime-sulfur dip such as Naturasil.

Papules on the face, ears and dog paws

dog skin fungusPicture of Dog Skin Fungus By:

Fungal condition called Dermatophytosis treated with prescription medications that contain  Grisseofulvin or Ketoconazole. Can benefit from anti-fungal dog shampoo therapy.

Dog skin redness, discolored skin spot (called a macule),  papules in areas where little or no hair is found, including fluid filled bumps in those areas, particularly in the dog's scrotum, chin, pelvis, paws, back of the abdomen

dog skin allergyDog Skin Allergy Picture By:

Dog skin allergies or hypersensitivity treated with anti-inflammatory steroids or identification and avoidance of the environmental allergen (if possible)

Uncontrolled cell growth resulting in a skin tumor or neoplasm - referred to as a dog mast cell tumor

dog mast cell tumorDog Mast Cell TumorBy:

Removal with surgery

Skin Issues in Dogs by Breed

Dog breed can also provide some clues when it comes to skin conditions, particularly in purebred dogs. Since these dogs are bred for certain traits, they also tend to pass on the same undesirable traits, including skin disease. Disease is also passed on genetically through line or in-breeding when a small stud population is used for breeding. Dog skin problems can be limited to one litter, one breed, or could be seen across certain breeds. Some of the more common breed specific canine skin diseases and conditions are described below:

Breed Specific Diseases and Conditions Canine Skin


Dog Skin Disease

Treatment Options

Standard Poodles

Miniature poodles


Belgian shepherd dogs



Canine Sebaceous adenitis: This disease is characterized by follicular casts. The casts are skin cell debris (keratinous debris) around the base of the hair shaft. Other symptoms include dog hair loss (alopecia) on the top of the head, back of the ears, at the tail and on the fore limbs.

The condition is diagnosed by examining a skin biopsy. Any diagnosis needs to differentiate (confirm the presence of this condition) vs. conditions that have similar symptoms such as leishmaniasis (infection caused by protozoa), demodicosis (a type of mange) and superficial pyoderma (dog skin infection).

Note that in the Vizsla only, a form of sebaceous adenitis, granulomatous sebaceous adenitis is found. Symptoms include localized hair loss (in a specific area on the body) and raised skin lesions,

dog sebaceous adenitis
Canine Sebaceous Adenititis


Prescription medications such as cyclosporine used and then decreased in dose as healing begins. In chronic cases, steroid therapy can help. 

Antibiotics are used to treat any skin infection (pyoderma)

German shepherd

Gordon setters

English setters

Large breed dogs

Canine Symmetrical lupoid onychodystrophy: This dog skin condition is characterized by the loosening or shedding of the nails. The cause is unknown.

Other symptoms include:

  • lameness
  • claw licking of the lesions
  • pain caused by skin infection or nails that remain on the dog

Diagnosis of canine symmetrical lupoid onychodystrophy is via a biopsy, skin culture and x-rays. The x-rays can also help to determine if the condition has caused any skin infections.   

dog symmetrical lupoid onychodystrophy
Canine Symmetrical Lupoid Onychodystrophy

It is possible that on rare occasions the condition will heal on its own. Treatment involves removing affected nails (anesthesia required) and then  bandaging the feet for 48 hours. Long term use of antibiotics (doxycycline or cefalexin, niacinamide) are used to control infection.

Labrador retrievers

American bull terrier

Staffordshire bull terriers


Interdigital cystic folliculitis/furunculosis: Symptoms of this dog skin problem  are comedomes (keratin and sebum located within the dilated orifice of a hair follicle) and
and follicular cysts (enlargement on the skin follicle) that develop in the ventral interpad skin on the dog paws.

As weight is placed on the paws, overgrowths occur.

Dog Interdigital cystic folliculitis
Dog Interdigital Cystic Folliculitis

The condition is treated with antibiotics and possibly topical steroids. Most dogs with the condition require long term use of antibiotics.

Bull terriers


Bassett hounds

Solar induced canine actinic dermatitis and squamous cell carcinoma: this condition occurs in dogs from sun exposure. As you could expect, dogs that live in sunny climates have a higher incidence of the disease.

Symptoms of actinic dermatitis appear in dog skin areas that are not protected by hair such as the abdomen and groin. Dog skin symptoms include:

  • Skin redness
  • Scaly and thick skin
  • lack of skin pigment
  • follicular cysts (cysts at the base of the hair)
  • sun induced
dog solar induced actinic dermatitis
Canine Solar induced actinic dermatitis

Treatment involves the use of retinoids (vitamin A derivative), but only of some benefit.

Some veterinarians see potential in the use of the topical medication immune modulator imiquimod and the
NSAID diclofenac gel.

There is a risk of a dog relapsing if  there is continued sun exposure. Dogs need to be re-examined every 6 months.

If a lesion becomes cancerous (squamous cell carcinoma) then surgical removal is required.


The treatment of canine skin diseases and conditions depends on the exact disease or condition. Treatment may involve oral or topical medication. It may also involve removal of any lumps or bumps from your dog's skin. If your pet's skin is affected by poor nutrition, treatment will involve making a correction in the diet.

There is a myth that baths are not good for dog skin diseases and conditions. This is not correct as bathing is an important part of just about every skin treatment. Shampoos are particularly effective on bacterial and fungal infections with a medicated bath 1 - 2 times per week.  They also help to remove any allergens that are caught in the dog's coat.

If a bacterial has progressed deep into the skin then antibiotics are needed. You should also carefully look at your dogs diet and if it is causing any of the canine skin problems. Follow this link to understand Dog Food for skin or sensitive skin dog food.

For dry skin, If all other causes are ruled out, then you might want to consider using oil for dry dog skin.

You can also fill out the form below where you can ask a free canine skin question. Our veterinarian answers several questions a week.

Treating Mild Allergic Skin Reactions

Approximately 1.2% of visits to a veterinary emergency room are for what are called mild allergic reactions. Vets refer to these as Type 1 hypersensitivity reactions. These skin reactions are triggered when skin cells called basophils and mast cells and the immunoglobulin E antibodies on the surface of those cells come in contact with an allergen. The contact can occur via injection, inhalation, ingestion or direct contact.

When the cells come in contact with the allergen they release prostaglandins, leukotrienes and histamine. In turn you start to see an allergic reaction including:

  • Urticaria (skin rash)
  • Pruritus (itchy skin)
  • Angioedema (skin swelling, hives)
  • Anaphylaxis ( a chronic life threatening allergic reaction that could result in issues with heart function and heart collapse)

Treatment usually takes one of two forms:

  1. Use of the medication Diphenhydramine (2 mg/kg IM once)
  2. Oral diphnhydramine (2 mg/kg PO every 8 hours for 2 to 3 days)

While Doctors used to prescribe a corticosteroid during the first treatment, research now shows that this is not necessary and does not improve the outcome.(16)

Ask Our Vet A Question or Share Your Story

Have A Question about Your Dog's Skin Condition? Our Team Will Answer It for Free!

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Our editors will pick 1 question to answer each week. Please include your dog's age, breed, medical history, medications and if possible, a picture of the condition.

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Brochures on Skin Disorders in Dogs

Understanding the causes and prevention of dog skin sores caused by parasites.
Available in a free Ebook

Understanding the causes of hair loss in dogs.
Available in a free Ebook

Dog skin infections pictures, types, symptoms and treatment.
Available in a free Ebook

References for Skin Disease in Dogs

(1) Swaim SF, Henderson RA (1990) Small Animal Wound Management Lea and Febiger, Philadelpha, pp 52-86

(2) Skin and coat care of the atopic dog. Laura Navarro Combalia. Departamento de Patologia Animal. Facultad de Veterinaria. Universidad de Zaragoza. Clinica Veterinaria August. Zaragoza. October 2012.

(3) Food Allergy Dermatitis; S. Colombini Osborn; Southwest Veterinary Dermatology, 2006

(3) Washington State University

(4) Carmichael, L. Recent Advances In Canine Infectious Diseases

(5) Management Challenges in Canine Pyoderma
Peter J. Ihrke, VMD, Diplomate ACVD

(6) Treatment of Canine Generalized Demodicosis; R.S. Mueller, Faculty of Veterinary Medicine, Ludwig-Maximillians-University, Munich, Germany

(5) School of Veterinary Medicine, University of California,
David Scott, D. W., Miller, W. H., Griffin, C. E.Muller and Kirk’s Small Animal Dermatology

(6) Canine and Feline Demodicosis
Didler-Noel Carlotti Dr. vet DIP ECVD
Eysines (Bordeaux), France EU

(7) Sarcoptes, Demodex and Otodectes: Treatment Options, R.S. Mueller, Faculty of Veterinary Medicine, Lugwig-Maximillans-University, Munich, German

(8) Dermatophytosis: Still Underdiagnosed & Overdiagnosed. Dr. Peter J. Ihrke

(9) Viral Diseases of the Dog, Remo Lobetti, PHD, Internal medicine Braystron Veterinary Hospital

(10) A Standard of Care, Flea Allergy Dermatitis. Peter F. Ihrke, VMD, Diplomate ACVD, Professor of Dermatology, School fo Veterinary Medicine, University of California.

(11) Merck Veterinary Manual, Flea Allergy Dermatitis

(12) Canine Osteosarcomas
Alfred M. Legendre, DVM, MS DACVIM
College of Veterinary Medicine
University of Tennesse, Knoxville, TN

(13) Wandering Through the Autoimmune Dermatosis: Pemphigus Complex
Carlos Eduardo Larsson

(14) Sun-Induced Skin Lesions in Dogs
Alexander Werner, VMD, DACVD
Animal Dermatology Center

(15) Understanding the Language of the Skin, Peter Hill, BVSc, The Royal (Dick) School of Veterinary Studies

(16)  Vet Emerg Crit Care (San Antonio). 2021;31(3):380-386