Could the shampoo you're using cause problems for your dog? Whether you follow the rules or not, most dog owners have heard it said that dogs should never be confused for people at bath time. Shampoos, as far as the rules are concerned, are species specific.
"But why?" you may well ask. "And who makes these rules anyway?"
The self-described skeptics among you may take an even harder line, certain as you are that the term "dog shampoo" is a mere marketing ploy and that the difference between the off-the-shelf people suds and the pricey pet store stuff comes down to packaging alone.
The truth, as with most things, lies somewhere in between how the rules read and what the hard-line skeptics say. In this case, however, I tend to side with the rule-makers. They are, after all, degreed and credentialed dermatologists who didn't come up with their rules just to turn a buck off "Fluffy's Finest Scrub-A-Dub Shampoo."
Nonetheless, there are some reasons to fault the party line suggesting that people shampoo and dogs should remain forever parted. Which is why I offer you this explanation and their rationale… so that if you do choose to break them, you'll know what you're risking.
Why Human Shampoo is Not the Same as Dog Shampoo
Here's the simple explanation for why human shampoos and dog shampoos are not created equal: Dog skin and human skin are not alike in many ways.
Here are the two we tend to care most about when it comes to shampoos:
People skin is more acidic than dog skin.
People have sweat glands and dogs don't (not on their haired skin, anyway).
While there are more differences – and some of them do impact the chemical makeup and consistency of shampoo formulas – these are the most commonly cited. Perhaps that's because a shampoo that's too acidic (because it's pH balanced for humans) and/or too harsh (because it's designed for those with moister skin) can lead to dryness and irritation, the most often observed outcomes of an inappropriate shampoo selection.
But there are more perils than just these. The skin is, after all, a major organ that plays a huge role in immunological defense. By drying the skin we're stripping the oils and the top layers from an animal's skin, thereby compromising the body's natural barrier against infection. And when these defenses are disrupted, the skin – indeed, the entire dog – can become predisposed to infections (usually by the yeast and bacteria that live on the surface of the skin).
The risk of a contact irritation is always a possibility too, whether we're dealing with pet products or human formulas. With dog shampoos, however, manufacturers will have typically undertaken simple trials on dogs to determine whether the risk of such an irritation is likely, whereas human shampoos are seldom (if ever) tested on domesticated dogs (and certainly never with the goal of protecting them from any harm).
So here's where you ask: "How does that explain the fact that I've always used my own shampoos on my dogs and never once witnessed a reaction?"
Why Doesn't All Human Shampoos Adverse Affect Dog Skin?
The truth is that not all human shampoos will react adversely with dog skin.
Here are a few reasons why:
- The variability in the pH of dog skin (which can actually differ dramatically among certain breeds of dogs) may be one explanation. In this case, your Schnauzer's more acidic skin might do well with your own shampoo, while your Lab's might get all red and flaky.
- Many adverse reactions are frequency-dependent. In other words, you may not be using the shampoo often enough to see a bad reaction.
- Moreover, a very soiled and dirty dog might well require a stronger ("harsher") cleanser to get all the stuff off. And if you don't use a ton of shampoo, you might not be putting the skin at much of a risk at all.
- Individual variations in the skin of dogs can make all the difference. That's why some dogs will seem "overly-sensitive" to shampoos while others can take just about any shampoo you throw at them.
So what's the upshot?
As a veterinarian, my personal preference is all about reducing risk. Which only makes sense seeing as I tend to only treat dogs who have already suffered reactions. And how much cheaper is the human stuff, anyway? Why NOT use the dog specific shampoos?
Having said that, it's also the case that dog shampoos can prove equally, if not more problematic for certain dogs. Turns out that, as with dog nutrition, this is one area where there are no guarantees that a product will work well for you. As with many other things in your dog's life, common sense – along with trial and error – is probably your best approach.