Topical application of heat-killed bacteria (ie, Lactobacillus spp, Vitreoscilla filiformis) has been reported to help in the treatment of atopic dermatitis in humans and mice.^1-4 There have been no investigations into the use of a similar product in atopic dogs. 

The current study* evaluated use of a spray containing heat-killed lactobacilli (ie, L rhamnosus, L reuteri) in 10 nonseasonally allergic pet dogs. The spray was applied to the ventrum every 24 hours for 28 days. Clinical scores (ie, canine atopic dermatitis extent and severity index 4 [CADESI-04], pruritus visual analog scale [pVAS]), skin barrier function, and pet owner assessment were obtained on days 0, 14, 28, and 42. The cutaneous microbiota were analyzed on days 0 and 28. There was a significant reduction in CADESI clinical severity scores at each time point as compared with those on day 0 and in pVAS on day 42. Significant changes in cutaneous microbiota and skin barrier function were not observed. Owners reported the spray was easy to apply.

Key pearls to put into practice:

A spray containing heat-killed Lactobacillus spp may be useful in the treatment of canine atopic dermatitis. This product may appeal to those owners with an increased interest in natural and alternative treatments. Larger-scale, blinded, placebo-controlled studies are needed to confirm the benefit of this product.

It is not fully understood why application of a heat-killed bacterial product helps treat allergic patients, but it may be due to an effect on local and systemic immune responses. Bacterial populations can have profound effects on the host’s immune system that may help ameliorate the clinical signs of some diseases (eg, atopic dermatitis). Greater understanding of the relationship between bacterial populations and disease may yield opportunities for new therapeutic options.

Treatment for atopic dermatitis is not limited to medication that stops itching. There is a wide range of therapies and products available. The most successful treatment includes a variety of products chosen based on evidence-based rationale. Therapy for clinical signs, allergen-specific immunotherapy, and topical products should be included as part of management in allergic patients.