Folliculitis in Dogs: What it is, How to Treat it

By: Trupanion Staff | Published Sep 21, 2023

One of the most common skin conditions in dogs, folliculitis is inflammation of the hair follicles, often caused by bacteria. Folliculitis occurs when a healthy hair follicle is compromised, leading to an overgrowth of the bacteria normally present on the skin. Underlying systemic disease, local trauma, or a specific skin condition can cause folliculitis in dogs, and you will need your veterinarian’s help to determine the true cause of this skin infection.

What causes folliculitis in dogs?

Folliculitis in dogs is most commonly caused by bacteria, but other culprits include parasitism, fungal infections, systemic disease, immune system disorders, endocrine issues, and local trauma. Your dog’s folliculitis may be caused by the following conditions:

• Canine acne
• Skin-fold pyoderma
• Interdigital pododermatitis, or cysts
• Idiopathic furunculosis (in German shepherds)
• Pyotraumatic folliculitis, or “hot spot”
• Callus dermatitis
• External parasites, such as fleas, ticks, mange mites, ear mites, and flies
• Allergies
• Fungal infections, such as ringworm and blastomycosis
• Acral-lick granuloma
• Hypothyroidism
• Cushing’s disease
• Immune system disorders

Essentially, folliculitis can flare up in your dog if the hair follicle becomes irritated, damaged, or infected for any reason.

How is folliculitis in dogs diagnosed?

It can be challenging to diagnose the correct cause of dermatologic conditions, and thus to determine appropriate treatment. In addition to a thorough medical history and physical exam, your veterinarian may perform an extensive array of diagnostic tests to determine the cause of the follicle infection, that may include:

• Skin scraping to detect mites
• Visual examination for fleas or ticks
• Skin cytology to search for yeast or bacterial organisms
• Wood’s lamp examination for ringworm
• Fungal culture
• Skin biopsy and histopathology
• Bacterial culture and sensitivity
• Testing for endocrine disorders, such as Cushing’s disease or hypothyroidism

The road to a correct diagnosis and complete resolution may be long, which makes proactive protection of your pet with a pet health insurance policy critical.

Signs

While folliculitis can occur wherever your pet has hair follicles, the most commonly affected areas include the armpits, groin, and abdomen. Short-haired dogs will present with raised tufts of hair covering papules or pustules, while long-haired dogs can hide their signs more easily. White- or light-colored dogs will display swollen brown or reddish areas on their fur. In general, dogs with folliculitis will show a variety of signs, depending on the cause and severity, which may include:

• Swelling
• Redness
• Itching
• Pustules or pimples
• Hair loss
• Papules (i.e., reddish swellings)
• Hyperpigmentation
• Epidermal collarettes (i.e., circular areas of hair loss, with crusting or scaling)
• Draining tracts
• Pain around the affected areas
• Blackheads

Early signs may be subtle and difficult to detect, but if you notice a difference in the luster, coarseness, shedding, or dryness of your pooch’s coat, schedule a visit with your veterinarian.

Treatment

Never start treating your dog's folliculitis (or any skin condition) on your own without first talking with your veterinarian. Certain products may irritate the skin further and worsen the symptoms your pet is experiencing. Proper diagnosis and assessment is necessary for treatment.

Once your veterinarian has discovered the cause of your pooch’s folliculitis, they can help you tackle an appropriate treatment plan. Canine folliculitis treatments may include:

• Bacterial folliculitis — An extensive treatment course may be required to fully eradicate deep-seated pyodermas. Bacterial folliculitis treatment often takes a three-pronged approach that uses topical medications, oral antibiotics, and management of the underlying cause. Topical medications include antimicrobial shampoo, creams, ointments, and sprays that may be combined with oral antibiotics for a lengthy treatment course to fully eradicate the bacterial infection.
• Fungal folliculitis — Fungal folliculitis treatment may include topical medications and medicated shampoos. Some fungal diseases, such as blastomycosis, may require systemic antifungal medication for several months to rid the body of the fungal organisms.
• Endocrine disorder folliculitis — This infection can be treated only if the underlying condition is managed. Fortunately, hypothyroidism in dogs is relatively simple to manage with daily medication. Cushing’s disease, however, can be more complicated to treat, and lifelong medication with or without surgery may be necessary.
• Parasite-induced folliculitis — Folliculitis caused by parasites requires treating the external parasite, in addition to managing the infection left behind by biting, chewing insects. Flea and tick preventives need to be administered regularly to protect your pup from all life stages of these pests, while mange mites can be destroyed with shampoos and oral medications.

Keep in mind that many folliculitis cases have an underlying cause that must also be treated to successfully eradicate your pooch’s pustules and papules. A simple course of canine antibiotics may be enough to treat a mild folliculitis case, but additional treatment is often necessary.

Dog breeds prone to folliculitis

While folliculitis has no breed predilection, and can affect any pet, the underlying conditions that commonly lead to its development are more likely to occur in particular breeds. For example, breeds that are prone to developing skin allergies that can lead to folliculitis include:

• Boston terriers
• Boxers
• Chinese Shar-peis
• Dalmatians
• Golden retrievers
• Labrador retrievers
• Lhasa apsos
• Shih tzus
• Scottish terriers
• West Highland white terriers
• Wirehaired fox terriers

Metabolic diseases that increase the likelihood of folliculitis development, such as Cushing’s disease or hypothyroidism, also affect specific breeds more commonly than others.

Canine folliculitis prevention

Some folliculitis causes can be prevented, but most cannot. For example, folliculitis triggered by a flea allergy can be avoided by keeping your pup on year-round quality flea-prevention medication. If your dog’s folliculitis is due to an underlying systemic disease, such as hypothyroidism or Cushing’s disease, prevention is not possible, but you can successfully manage the disease to avoid follicle infections.

While some folliculitis cases are mild and resolve quickly, others can take months of intensive antibiotic or antifungal therapy. Occasionally, lifelong management of endocrine dysfunction is necessary to keep your furry pal from erupting in pustules and papules. That said, you can ensure your pup has healthy skin and fur by maintaining a strong relationship with your veterinarian.

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