Folliculitis is an infection that begins in the hair follicles. In mild folliculitis you typically will find many small pustules with a hair shaft protruding through the center of each. Dogs with mild cases may have rings of scales around the follicles. Once the follicles become infected, the infection can bore deeply into the dermis, forming large pustules and furuncles that rupture, discharge pus, and crust over. Draining sinus tracts develop in cases of deep folliculitis.
Folliculitis usually involves the undersurface of the body, especially the armpits, abdomen, and groin. A condition called Schnauzer comedo syndrome is common in Miniature Schnauzers. Dogs suffering from this disease have many large blackheads running down the middle of their back.
Folliculitis often occurs as a secondary complication to scabies, demodectic mange, seborrhea, hormonal skin disease, and other problems. Some cases are caused by vigorous grooming, which traumatizes the hair follicles.
Treatment: It is important to identify and treat the underlying cause as well as the folliculitis.
Mild cases should be treated as described for acne. Deep folliculitis requires vigorous topical and systemic therapy. Clip away the hair from infected skin on longhaired dogs (don’t clip shorthaired dogs), and bathe the dog twice a day for 10 days with a povidone-iodine shampoo such as Betadine or one with chlorhexidine such as Nolvasan. As the skin infection improves, switch to a benzoyl peroxide shampoo such as Stiff OxyDex, OxyDex, or Pyoben, used once or twice a week. Continue until healing is complete.
The dog should also be placed on an oral antibiotic selected on the basis of culture and sensitivity tests. Continue oral antibiotics for six to eight weeks, including at least two weeks beyond apparent cure. Treatment failures occur when antibiotics are stopped too soon or used at too low a dosage. The pro- longed use of corticosteroids should be avoided in dogs with folliculitis.