Last week I wrote about the recently updated ISCAID antimicrobial use guidelines for canine pyoderma, specifically regarding surface pyoderma. The full guidelines are freely available online (Loeffler et al. Vet Derm 2025). Today I’m going to cover the highlights about the “big one”: superficial folliculitis. I call it the big one because it’s so common in dogs, and it’s the one where we can have a big impact by convincing more people to using topical treatment as the first option, instead of reaching for systemic antimicrobials.

The three most important points to remember about superficial folliculitis in this context are:

  • It’s a staph-driven disease.
  • It basically always has an underlying cause, particularly allergies (e.g. food, flea, atopy). If we don’t address the underlying cause, the infection will inevitably come back. Too often, the underlying cause doesn’t get addressed, or doesn’t get addressed until multiple rounds of infection have occurred.
  • It’s a superficial infection, so we can approach it from the surface (topically). 

Here are the main treatment recommendations from the new guidelines. For full details, as well as information about diagnosis and other issues, check out the complete document.

  • Diagnosis is based on clinical signs and cytological analysis (cocci and neutrophils)
  • Topical antimicrobial therapy as the sole antibacterial treatment is the treatment-­of-­choice. The best evaluated treatment is 2-4% chlorhexidine.
  • Response to topical therapy should be re-­assessed by a veterinarian after 2–3 weeks of treatment.
  • Topical treatment should be continued until the lesions have resolved and underlying problem has been addressed (when possible).

When are systemic antimicrobials indicated for superficial folliculitis?

This choice is mainly based on owner and patient factors, not the disease. There are no clinical reasons to use systemic over topical antimicrobial therapy alone. However, if the owner cannot or will not treat the dog topically, then systemic antimicrobials are indicated. Systemic antimicrobials can also be considered if there has been no response to 2 weeks of topical treatment, but other causes (e.g. uncontrolled underlying disease, or a different disease) are more likely if compliance with the topical treatment was actually good and there was no response.

Culture and susceptibility testing is recommended if systemic antimicrobials are used. It’s particularly important if there are risk factors for resistance, such as previous rounds of antimicrobial treatment. 

  • The authors of these guidelines had a lot of debate about this. Ideally, we culture every time we’re thinking about using a systemic antibiotic. If the animal is not at high risk of having a resistant infection, culture is less valuable, and cost becomes an issue, so it’s fair to not culture cases where the risk if resistance is likely low. However, it’s best practice to culture whenever we can.

Additional treatment recommendations from the new guidelines include:

Clindamycin, cefalexin, cefadroxil and amoxicillin-­clavulanate are the recommended first line options for superficial follicultis if systemic antimicrobials are warranted. 

  • If there’s a suspicion (based on cytology) that the infection is not caused by staph, then a culture would be indicated because these drugs focus on staph.
  • Adjunctive topical treatment should be used in addition to systemic antimicrobials whenever possible. 

How long should systemic antimicrobials be given?

  • “An initial 2-­ week course may be dispensed, and an appointment for re-­examination by a veterinarian should be scheduled before the end of the course to determine whether systemic treatment can be stopped or whether longer treatment is required.”
  • “Clinical resolution of superficial pyoderma can be assumed, and systemic antimicrobials stopped when primary lesions of pyoderma (papules, pustules and erythematous epidermal collarettes) are no longer found.”

Long-term management of superficial folliculitis

  • Addressing the underlying disease is critical. It can take time and money, but will reduce disease (and also ultimately save time and money).
  • Regardless of whether systemic or topical treatment is used, “topical treatment can be continued longer than systemic therapy, and is potentially life-­long, where the primary causes cannot be resolved and the risk of recurrence remains.”
  • “There is no evidence to support extending systemic antimicrobial therapy beyond the resolution of clinical signs associated with infection; instead, underlying primary causes must be identified and addressed.”

Up next: recommendations on the nastier and more complicated condition, deep pyoderma.