September 11, 2020
Topical therapy should always be considered in management of canine atopic dermatitis. Not only when an active pyoderma is present, but as long-term maintenance to prevent recurrence. It is particularly valuable for controlling chronic, recurrent cases of Staphylococcus sp. to avoid development of methicillin resistance. Topical therapy may decrease the length of time, or even eliminate the need for systemic antibiotics.
Certain topical therapies not only decrease bacterial populations and reduce surface recolonization, they help restore the epidermal barrier. The epidermal barrier has been shown to be abnormal in the skin of atopic dogs even if it is non-lesional. This emphasizes the importance of utilizing restorative topical products even in well-controlled atopic patients. Used as a part of the maintenance protocol, it can minimize the use of systemic allergy medications needed for management.
Many topical formulations are available. However, bathing with high-quality shampoos is the preferred method if the dog will allow it and the client is able. Since dogs with bacterial pyoderma often have atopic dermatitis, bathing also removes allergens from the surface of the skin. This helps reduce inflammation and pruritus the dog is experiencing from the primary disease.
The most common antibacterial agent found in shampoos is chlorhexidine. It is generally well tolerated and not irritating. It is important to use products that contain 3-4% chlorhexidine if it is the sole active ingredient against the pyoderma (most commonly Staphylococcus pseudintermedius). However, 2% chlorhexidine has been shown to have a synergistic effect with miconazole if a combination product is selected.
Benzoyl peroxide shampoos are available and have been shown to have antibacterial and follicular flushing properties. However, watch for xerosis (dry skin) and irritation if using this ingredient on a more regular basis.
A recent study showed promise for the use of a shampoo with a combination of salicylic acid and sodium hypochlorite as active ingredients.1 Dogs were bathed with the shampoo three times weekly for 4 weeks and 17/19 dogs completed the study with positive results. This could provide an alternative for chlorhexidine based products in difficult pyoderma cases.
Bathing frequency depends on the severity of the case and the owner’s willingness to bathe. If you have a proactive owner, then many cases of pyoderma (even if resistant) can be managed with a bathing protocol alone. Cases of pyoderma typically benefit from frequent bathing (every 2 to 3 days) initially, followed by weekly maintenance. Contact time is another important aspect of a bathing protocol. Instruct owners to leave the shampoo on the skin for at least 5 (preferably 10) minutes before thorough rinsing.
It is highly recommended to talk to owners about the benefit of a consistent bathing protocol for their allergic pets. Not only for infection, but overall management of the skin.