Unlock dermatology secrets to realize treatment success

Unlock dermatology secrets to realize treatment success

Feb 01, 2006

After finishing my residency at the University of California-Davis in 1994, I decided to remain on as a clinical instructor for an additional two years prior to starting my dermatology career in private practice. I really didn't know what I was getting into.

What I learned (and continue to learn) are wonderful and useful tidbits of knowledge that have allowed me to practice the highest quality of medicine. Here they are in no particular order.

Treatment of recurrent pyoderma

Generally speaking, most cases of canine superficial pyoderma are cleared with one course of antibiotics, provided that it is an appropriate choice for Staphylococcus and the dosage and duration are adequate. The choices and dosages for antibiotics are listed below:
  • Cephalexin 22mg/kg, orally BID
  • Trimethoprim/sulfa 14mg/kg BID
  • Ormetoprim/sulfa 55mg/kg once daily for 1 day, then 27.5 mg/kg once daily
  • Cefpodoxime 5-10mg/kg once daily
  • Enrofloxacin or ciprofloxacin 5 mg/kg once daily (I prefer 10 mg/kg, or higher)
  • Marbofloxacin 1.25 mg-2.5 mg/kg once daily
  • Clindamycin 15-20 mg/kg twice daily
  • Lincomycin 22mg/kg twice daily
  • Amoxicillin/clavulanic acid 20 mg/kg twice daily.

It's always important not to underdose. For example, if a dog weighs 63 pounds (30 kg), I prefer 750 mg cephalexin twice daily rather than 500 mg twice daily. It is crucial that antibiotic therapy be administered for at least 21 days for superficial pyoderma, and at least 45 days for deep pyoderma. Some specialists advocate the use of antibiotics for two weeks beyond clinical cure. Most veterinarian dermatologists prefer twice daily cephalexin, as three times daily may not be superior. Finally, aggressive topical therapy can aid in the delay or possibly in the prevention of pyoderma. I prefer shampoos that contain benzoyl peroxide with or without sulfur.

Treatment of itchy dogs with pyoderma

There is a phenomenon called corticosteroid interference. Most clinicians that deal with refractory pyoderma in the dog have found the concurrent usage of corticosteroids (particularly high dosages) to occasionally interfere with antibiotic therapy for pyoderma. The exact mechanism is not known, but it appears that corticosteroids may inhibit the immune system's capability to eliminate or neutralize bacteria, thus interfering with clearance of the pyoderma.

Pruritic considerations

In private practice, we are all faced with the decision to prescribe anti-pruritic medications to allow our patients to experience relief. Our clients and our colleagues have been sensitized to the possible adverse side effects of corticosteroids, and as a consequence, some animals continue to remain pruritic and uncomfortable. I feel that when appropriately administered and not continued long-term, corticosteroids are immensely helpful and safe.

Example 1: A 2-year-old German Shepherd with fleas and clinical signs compatible with flea allergy is presented. Pyoderma is not evident. It's unlikely an extraordinarily flea-allergic dog will benefit from oral fatty acids therapy combined with an antihistamine. Knowing that there can be a fairly long lag period (up to three weeks or longer) for a flea control program to take effect, it seems reasonable to prescribe a short course of a tapering dosage of prednisone. This will break the itch-scratch cycle, and it gives the patient much needed relief.

Example 2: An 8-year-old Black Labrador with pruritic, superficial pyoderma is presented to the attending clinician. According to the owner, only the lesions are pruritic. There are many cases of pruritic pyoderma in the dog, and many cases do not require corticosteroids, as the Staphylococcal infection is contributing solely to the pruritus. We are aware now of the corticosteroid interference phenomenon, so "toughing it out" for two to three weeks (possibly with an Elizabethan collar) would be advised while the antibiotic takes effect.

Treatment of autoimmune diseases in the dog and cat