Pyoderma in small animals is usually seen as a complex of bacterial infections at different levels of the skin, with each form requiring a slightly different approach. It’s important in all forms to identify, treat and manage the underlying triggers such as allergies, endocrinopathies, immunodeficiency, ectoparasitic infestation and follicular dysplasia.
Posted: 25 June 2020
There are also some breeds which are more predisposed to some of these problems, including the West Highland White terrier and Basset Hound. Whilst diagnosis of underlying conditions may be complex and frustrating, any treatment offered at the same time as trying to make a diagnosis, should be aimed at helping the patient without complicating the end result.
1. Systemic antibiotics – the primary treatment choice
In most cases this is achieved by the empirical use of antibiotics, which can effectively treat the pyoderma and help expose any underlying conditions. These are usually given for a minimum period of 3 – 4 weeks, and at least until all lesions have resolved for at least 7 days. Any less than this and there is a real risk of the condition recurring. Chronic cases, and cases which progress to being deep pyoderma, generally need 2 -3 months of antibiotics.
Which systemic antibiotics are recommended for pyoderma?
The most frequently used first choice antibiotics for a bacterial pyoderma are;
At present, the following antibiotics are usually found to be ineffective against the common presentations of pyoderma;
MRSA – the risk of resistance
Most cases of pyoderma tend to be treated with systemic antibiotics, though this does pose a real risk of the animal developing MRSA (methicillin-resistant Staphylococcus aureus).
MRSA is an increasing problem in both the human and animal populations throughout the world, and many clinicians are becoming more and more concerned of the risk of a real antibiotic resistance crisis developing throughout society. We should therefore, as far as possible, use specific and narrow spectrum antibiotics to minimise the development of resistance. In most cases, and especially with recurrent cases of bacterial pyoderma, the choice of antibiotics must be based on the results of culture and sensitivity.
It’s also particularly important to avoid the use of fluoroquinolones and second/third generation cephalosporins unless culture and sensitivity tests confirm that these are your only options, to minimise the development of staphylococci resistant to multiple antibiotics.
2. Topical antibiotics
Resistance to systemic antibiotics warrants the use of topical therapies which can reduce or even eliminate the need for systemic antibiotic treatment.
Neomycin is an aminoglycoside effective against many gram-negative pathogens. Whilst this antibiotic has been added to a variety of topical preparations for years, it’s now known to be more likely to cause a contact allergy than other topical antibiotic, especially with extended use, so should be used with caution.
b. Bacitracin and polymyxin B
These are effective against gram-negative bacteria and known to be more potent than other common topical antibiotics.
This is an effective topical antibiotic useful against superficial skin infections, including those caused by Staphylococcus spp. Importantly, cross-resistance with other antibiotics is uncommon. It can be useful in cases of deep pyoderma as it penetrates skin well without being systemically absorbed. Be aware that care must be used in cats with impaired renal function, as the base it comes in is toxic if large amounts are applied for extended treatment periods.
d. Silver sulfadiazine
This medication belongs to a class of drugs known as sulfa antibiotics and works as a bacteriostat. It’s used with other treatments to help prevent and treat wound infections as a result of burns, but can also be applied to areas of deep pyoderma. It is an effective topical preparation used against Pseudomonas and gram-positive bacteria, including Staphylococcus aureus.
3. Shampoos and washes
The use of shampoos containing chlorhexidine or benzoyl peroxide is also an important form of topical therapy, as the physical cleaning helps to remove bacteria, excessive sebum, oils and dead skin. Chlorhexidine seems to be the most effective additives. For shampoos to be effective you certainly need a committed owner who is prepared to get themselves and their bathroom wet.
Shampoo ingredients that are known to be effective include;
With almost all forms of superficial pyoderma, it’s important to avoid the use of glucocorticoids to manage pruritis if the itch is only mild. However, if the patient is struggling with intense pruritus, particularly in areas of skin which aren’t displaying evidence of pyoderma, then a two or three week course of prednisone may be indicated.
We need to be mindful that by using steroids in the presence of a pruritic pyoderma, it makes the interpretation of any response to antibiotic therapy impossible.
It’s also very important to never use glucocorticoids in cases of deep pyoderma.
With all cases of pyoderma, the coat needs to be cared for, so it’s important to discuss this and encourage the owner to take special care with grooming their pet. Some dogs will require their coat to be clipped, especially in cases of deep pyoderma. This will help remove excessive hair that will only act as a trap for dead skin, fomites, debris and bacteria. If the owner isn’t skilled or equipped to do the grooming, recommend a professional dog groomer.