Folliculitis, or more commonly known as bacterial folliculitis, refers to hair follicle inflammation that is usually caused by a bacterial inflection. In dogs, the condition can be caused not only by a bacterial infection, but by parasitic infestations, hormonal disorders, fungi infections, systematic diseases, or skin diseases. As a pet owner, here's what you should know about folliculitis in dogs.

Identifying Folliculitis in Dogs

Whatever the cause of the inflammation may be, canine folliculitis can be identified by checking for the most common symptoms, such as:

  • Swelling
  • Redness
  • Itching
  • Pustules (Pimples)
  • Hair Loss

While those are the most noticeable and easily recognized symptoms, also check for:

  • Hyperpigmentation, Darkening of the skin
  • Superficial Erosions, Raw spots on the skin
  • Draining Tacts, Large, firm, raised, and usually circular lesions
  • Papules, Reddish swellings on the skin
  • Epidermal Collarettes, Circular areas of hair loss with crusting or scaling around their borders
  • Pain, Often around the affected areas

To determine if the dog has folliculitis, a vet will identify the symptoms and will often do a diagnostic test including skin scrapings for mites, skin cytology, fungal culture, ringworm testing, bacterial culture, and sensitivity, or a skin biopsy and histopathology.

There are no specific breeds that are predisposed to having folliculitis, but there are some dog breeds that are predisposed to having skin diseases in general, or systematic diseases that can eventually lead to folliculitis.

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Causes and Treatments of Folliculitis in Dogs

Causes and Treatments of Folliculitis in Dogs

The most common causes of dog folliculitis are skin diseases. Skin diseases are created by an overreactive immune system response to allergies or specific infectious or environmental agents. As dogs instinctively scratch their skin, they produce tiny skin wounds that become infected with bacteria, leading to folliculitis or staph infection.

The nine most common skin conditions that may cause folliculitis in dogs are:

1. Callus Dermatitis

When a dog scratches and bites an affected area, they can create cracks in the skin that provide the warm, dark, and moist regions that encourage bacterial growth. Constant irritation forms calluses, which are most often found on their feet but may also be found on the chest, elbows, and hocks.

A callus may be possible protection of the skin, but where calluses reside, there can be the formation of small cysts around the hair follicles that may become irritated and cause bumps, blackheads, holes, or discharge on the callus.

Treatment: Vet diagnosis, antibiotics, and medicated shampoo for two to six weeks. Use soft bedding and maintain the dog at a healthy weight to reduce pressure placed upon the calluses.

2. External Parasites

Fleas are the most common external parasite found on dogs and can cause severe skin irritation when the dog is heavily infested. Other external parasites that cause skin irritation are ear mites, sarcoptic mange mites (scabies), ticks, and flies.

Treatment: Maintaining a well-groomed coat and preventative maintenance schedule, flea and tick medications, and topical ointments. Mite-killing or flea-killing treatments may be necessary to remove a current infestation before preventative maintenance can occur. Additionally, it may be helpful to invest in inflammation, reducing ointment to relieve the dog of irritation.

3. Interdigital Cysts

An interdigital furuncle, or interdigital cyst, are painful lesions located in the interdigital webs of dogs, as described and defined by the Merck Veterinary Manual. They are easily noticed by a welt, sore, or hairless bump located between a dog's toes.

They can be caused by allergies, excess weight, poor foot conformations, mites, ingrown hairs other foreign bodies, or yeast infections.

Treatment: Vet diagnosis, use of antibiotics/steroids/mite-killers, Epsom salt soaks, medicated cloths, or in dire situations, the removal of the webbing between their toes. A controversial procedure as it may cause problems of a different type.

4. Allergies

Allergies are caused by a state of over-reactivity of the dog's immune system to an allergen. Allergens can be anything from food to grass to fleas. If an allergic reaction is producing folliculitis, look out for signs of itching, coughing, sneezing, runny eyes and nose, and sometimes vomiting and diarrhea.

Allergies are widespread in dogs, with no predisposition to a specific age, breed, or body type.

Treatment: Most allergies can be treated at home by identifying what the allergen is and removing it from their vicinity or routine. If unavoidable or unidentifiable, the vet can prescribe allergy medication or may recommend monthly allergy shots depending on the intensity and frequency of the reactions.

5. Canine Acne

A condition similar to human acne that is prevalent in adolescent dogs, usually showing up at approximately 5-8 months of age.  They are red bumps and blackheads found on the chin and lips of younger dogs, and they can become infected and fill with pus causing the dog to scratch and increase the risk of bacterial infection in their skin.

Treatment: Acne is mostly an eyesore, but can become an issue when infected. A vet can prescribe a canine acne treatment that is safe for use. A change of diet and possibly a change in their bowl material, from plastic to ceramic or metal along with cleaning them daily may be recommended.

6. Fungal InfectionsFungal Infections

There are a variety of different types of fungal infections, but the most common is Blastomycosis, a systematic yeast-like fungal infection that occurs mainly in male dogs. The fungus is found in decaying wood and soil and thrives in wet environments, such as riverbanks, lakes, and swamps. Other infections include Ringworm and yeast infections.

Treatment: All types require a vet diagnosis and most often a biopsy or testing is done to determine the exact fungal infection, misdiagnosis is extremely dangerous as some symptoms are identical to those of cancer, bacterial infections, or other fungal infections. Depending on the type of fungal infection, the vet may prescribe a medicated bath, oral anti-fungal medications, antiseptic drugs, and infusing nasal passages with a liquid anti-fungal medication. Treatments vary in length with some being only two-four weeks and others extending through months.

7. Skin Fold Pyoderma

A skin fold pyoderma is a bacterial infection on the surface of the skin or the superficial or deep layers. This is usually caused by Staphylococcus intermedius, a naturally occurring bacteria in the skin that causes infection when the natural balance is disturbed. Major problems are rare; this infection typically only causes slight discomfort in addition to the folliculitis.

Treatment: Vet diagnosis, antibiotics, and medicated shampoo for two to six weeks.

8. Pyotraumatic Folliculitis

Also known as acute moist dermatitis or “hot spot” is a condition caused by self-inflicted trauma as an attempt to relieve pain in a particular area. They react and look like infections in the skin, but are not actual skin infections.

Treatment: Vet diagnosis to determine if there is an underlying cause for the reaction that may need medical attention. Otherwise, a combination of antibiotics and cleaning of the affected area with medicated shampoo and topical medication.

9. Acral Lick Granuloma

A small sore spot on the skin that was agitated by the dog which created a skin lesion. These are caused by a dog's need to continually lick an area, forming new granulomas. The skin becomes so profoundly affected that the base layer of skin can be inspected and shown to have scarred oil glands, inflamed capillaries, broken hair follicles, and pockets of bacteria.

Treatment: There is no specific treatment as this is self-inflicted by the dog without prior agitation. Even removal of the affected area is not a sufficient cure as the dog will do the same to the surgery spot. Assisting the dog with anxiety or other similar issues may help as this can be caused by separation anxiety.

Preventing Dog FolliculitisThe 9 Causes of Folliculitis in Dogs and How to Treat Them

The type of folliculitis is what determines how preventable it is. Keeping folds of skin on wrinkled dogs can help prevent it, as will maintaining stringent flea prevention.

Controlling hormonal imbalances and avoiding areas where the bacteria and fungus are prevalent can reduce the risk of folliculitis. Prevent itching in dogs using different methods and use an Elizabethan collar to stop the dog from licking/chewing at the area.

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