What Is Folliculitis In Dogs?

Is your pup having skin problems?

dog with magnified hair

If you recently noticed some red bumps on your dog’s skin, you might be worried and wonder what the deal is.

While allergies and fleas are common causes for red bumps on a dog’s skin, it’s possible your pup’s symptoms are actually being caused by a skin condition known as folliculitis.

We reached out to Dr. Fiona Lee, a veterinary dermatologist and medical director at Pet Dermatology Center, to find out what you need to know about folliculitis in dogs.

What is folliculitis?

Folliculitis is a skin condition that occurs when hair follicles (the place where the hair grows through the skin) become infected or irritated, leading to inflammation.

What causes folliculitis in dogs?

According to Dr. Lee, these are the most common causes of folliculitis in dogs:

  • Staphylococcus (Staph) bacteria — This bacteria lives on the skin, but under certain conditions, it can overgrow and cause infection.
  • Demodex mites — This is a parasite that lives at the roots of hair follicles. For dogs who have weak immune systems (like puppies or dogs receiving chemotherapy) or certain conditions, like Cushing’s disease or hypothyroidism, the mites can overgrow. (This is also the most common cause of mange in dogs.)
  • Ringworm — This is a fungal skin infection (it’s not actually a type of worm).

These can all be caused by an underlying condition, though. “For example, if a patient is immunosuppressed, then they're more prone to those organisms,” Dr. Lee told The Dodo. “One of the most common underlying reasons for bacterial folliculitis is allergies (flea, food, environmental).”

Signs of folliculitis

“Initially, there is a papule (red swelling) or pustule (yellow pimple) around a hair follicle,” Dr. Lee said. “Bacterial folliculitis can progress to a crust (scab) or epidermal collarette (circular lesion, clear in the center with a thin rim of dry skin).”

Here are some signs to look out for to spot folliculitis:

  • Papules
  • Pustules
  • Crusted skin
  • Epidermal collarettes
  • Redness
  • Swelling
  • Scaling skin
  • Itching
  • Hair loss
  • Hyperpigmentation
  • Pain near the hair follicle

Pet parents can sometimes confuse inflamed hair follicles with hives, so it’s good to know the differences.

“Hives [have an] acute onset, are extremely itchy, can form what look like large raised ‘continents’ on the trunk, and can progress to swelling, difficulty breathing, GI signs, etc.,” Dr. Lee said.

Folliculitis has a more gradual onset compared to hives, and the condition doesn’t cause systemic symptoms, such as gastrointestinal problems. The raised hair follicles are also smaller than hives.

To definitively diagnose folliculitis, your vet will need to perform a biopsy to look at the skin cells. “Almost always, cytology (looking at slides under the microscope) should be the first diagnostic in veterinary dermatology,” Dr. Lee said.

Your vet will also check for parasites and might perform tests to look for a bacterial or fungal infection.

How to treat folliculitis in dogs

For dogs who have folliculitis with no secondary infection, vets will prescribe an anti-inflammatory medication, such as steroids, Dr. Lee said.

The underlying cause will also need to be treated so the folliculitis doesn’t come back.

Treatment for allergies will depend on what your pup’s allergic to. For food allergies, your vet will prescribe or recommend a limited-ingredient or hydrolyzed protein dog food. Other allergy treatments include:

Ringworm is treated with antifungal cream and oral medication, while bacterial infections are treated with antibiotics.

Mites are treated with anti-inflammatory and corticosteroid creams, and your vet might recommend using a shampoo that contains benzoyl peroxide. In some cases, your vet will prescribe anti-parasitic medication.

If you notice signs of folliculitis in your dog, such as itching and red bumps, be sure to take him to the vet so his symptoms don’t get worse.