Time to move on from the old myth that oatmeal schampo feeds yeast infections on the skin.
There is an old myth going around on the internet that oatmeal schampos feeds yeast infections on the skin, as oatmeal is a carbohydrate and yeast feeds on carbs that transform into sugar.
“Because we all know that you need sugar when you bake bread so that the yeast can work and raise the bread……”
But let us take a step back and visit the science literature and learn what yeast on dogs actually is….
Because it is NOT the same as the yeast you use to make bread, it’s something completely different.
I am trying to write a short article this time just to give you an overview on the topic and not to bore the reader too much 🙂
When we talk about yeast on dogs, we talk about a fungal organism that is always present on the dog’s skin. It is part of the natural skin flora – the microbiota ( it’s the same for us -we also have yeast on our skin)
The fancy word for this is commensal. It is an organism that lives off another organism without causing any harm.
The yeast organisms live off the lipids on the skin- not carbohydrates. Lipids are made up of different types of fats and old skin cells. Science has even proved that they have lost genes involved in the metabolism of carbohydrates.
Which makes sense – there are very few carbohydrates on the skin, it is on the other hand plenty of lipids.
“This means that they need the supply of lipids in order to grow and, therefore, all the species in this genus are lipid-dependent, a fact that makes them unique among fungi. It is not surprising that this specific loss of genes is a consequence of their adaptation to living in the skin, which provides these species with all the lipids necessary for their growth. In this process, as these authors point out, these yeasts have increased their genetic arsenal with a multitude of lipid hydrolases that are necessary to utilise the lipids present in this environment. On the contrary, their genomes have lost genes involved in the metabolism of carbohydrates, which are not very abundant in the skin”
This is why we usually first see yeast infections in areas that have a larger amount of sebaceous glands such as ears, skin folds and paws. As there is where the food is.
Yeast organisms are also part of the skin barrier that helps to protect the skin against other pathogens, so they are actually important for the dog/us.
But why do some dogs get a problem with yeast?
The amount of yeast that is present on the skin is controlled by the immune system.
A normally functioning immune system can keep the yeast under control so that it helps the skin barrier.
But if anything happens and the immune system either gets busy dealing with something else or if the immune system in itself gets compromised, then you have an uncontrolled growth of the yeast. And that’s when it becomes a problem.
A large amount of yeast on the skin will cause inflammation and the inflammation can then open up for a bacterial infection. And this is why we often see a combination of yeast and bacterial infection in dogs with skin problems.
So now that we know that yeast that lives on the skin doesn’t eat carbohydrates, what about oatmeal shampoos?
Are they any good for dogs with yeast infections?
No, not really. Oatmeal doesn’t kill fungus/yeast. So it wont have any effect when the dog has that type of problem. It might ease some of the inflammation that the yeast is causing, and soothe the itching a bit, but it wont kill the yeast.
You will need to use a shampoo that is antifungal to do that. Like Malaseb, Duoxo or a chlorhexidine-based shampoo.
But the oatmeal wont dry out the skin. This is also a myth that is going around.
Colloidal oatmeal is actually a well-proven moisturizer, a soothing agent and has also been shown to have anti-inflammatory properties.
The reason why your mum put oatmeal on your rash when you were young, is because it stops the itching, not because it is drying out the skin.
Here is a small list of scientific articles that you can read and learn more about the benefits of oatmeal and its properties :
Mechanism of action and clinical benefits of colloidal oatmeal for dermatologic practice.
Colloidal oatmeal: history, chemistry and clinical properties
Anti-inflammatory activities of colloidal oatmeal
Colloidal oatmeal formulations as treatment in atopic dermatitis
Colloidal oatmeal improves the skin barrier
The Efficacy of Colloidal Oatmeal Cream 1% as Add-on Therapy in the Management of Chronic Irritant Hand Eczema: A Double-Blind Study
You can go on to Google scholar to find more articles :
I hope this breif explanation have helped you to get a better understanding of the topic and that you now can see past the old myths 🙂 .
If you want to read more about the topic of yeast infections :
Canine Malassezia dermatitis
Or read more in
Kirk &Muller Small animal dermatology 7th edition
BSAVA manual of Canine and Feline Dermatology 4th edition