Pyoderma is a bacterial skin infection, which can involve different layers of the skin. Superficial pyodermas are within the skin near the surface and can often be recognized by the presence of circular crusting lesions or red pimples. Deep pyodermas occur when bacteria invade structures beneath and beyond the hair follicle. This can be recognized in most cases because pus can be expressed from the skin lesions.

Staphylococcus intermedius is considered to be the prime bacterial pathogen of the skin. The bacteria rarely infect normal skin but can if there are injured or inflamed skin surfaces.

The development of pyoderma depends upon several factors. The most important is the host’s response to bacterial invasion. Some of the more common causes of recurrent or deep pyodermas are
1. Drug induced (cortisone = steroids)
2. Immune deficiency or depression
3. Hormonal (hypothyroidism, hyperadrenocorticism)
4. Allergic (pollen allergy, food allergy, flea allergy)
5. Parasitic (demodicosis, scabies, fleas)
6. Keratinization abnormalities (seborrhea)
7. Immune-mediated (pemphigus, lupus)
8. Fungal (ringworm)
9. Staph hypersensitivity (allergy to pet’s own bacteria)
10. Neoplasia (cancer)

The prognosis for most superficial pyodermas is good. The deep pyodermas are much more difficult to cure/control. The information gained from the laboratory tests will give us a more precise diagnosis and prognosis. Occasionally, after all of the causes have been eliminated, the pyoderma returns. In these cases, immune stimulating drugs will be tried.

The tests for diagnosing a pyoderma vary and depend on the severity and duration of the problem, previous response to treatment and initial clinical impression. The tests may include

TEST                                                             INITIAL CLINICAL IMPRESSION/INDICATION
1. Impression skin smear                             Bacteria, allergy, immune-mediated
2. Skin scrapings                                         Parasites
3. Fungal culture                                          Ringworm
4. Skin biopsies                                            Hormonal, immune-mediated, allergy, fungal, bacterial, parasite
5. Urinalysis                                                  Internal diseases
6. CBC, chemistry panel                              Internal diseases
7. Thyroid panel                                           Thyroid gland abnormality
8. Cortisol panel                                           Adrenal gland abnormality
9. Culture                                                     To determine bacteria type and antibiotic choice
10. Histamine test                                        Drug interference
11. Skin testing                                            Atopy (pollen allergy)

Treatment of pyoderma also can be quite variable. Correction or control of the underlying cause is one of our goals. All patients with a pyoderma diagnosis will need to be on antibiotics for a MINIMUM of 21 days. Topical therapy is often indicated in the form of special shampoos.

For more information on this subject, speak to the veterinarian who is treating your pet.