EYE IRRITATION FROM PET SHAMPOOS

 Do “soap-free” or “Tearless” have any real meaning or are they just marketing hype?  “Tearless” or even “tear-free” have very little meaning as there are no standard definitions or bench marks for use of these terms.  Anyone can use this claim, and many do. 

The ingredients that are the most likely to cause eye irritation are the surfactants, fragrances, colorants and preservatives. The pH of the whole product is also important, as a high (alkaline) pH is likely to be very irritating to eyes. This is where "soap-free" factors in. Soaps are strong surfactants with a very high pH. The pH of most soaps is 9.0-9.5. Because of the nature of the saponification process, the pH of hard soaps is not adjustable. It is what it is.  Detergent formulations can be tweaked to the desirable pH.  A 9.0 pH level can be quite irritating to the canine eye, and is why soaps are not a good choice around eyes or for facial products.

What else causes eye irritation from a shampoo? It is caused when the solution either contains a significant amount of an irritating ingredient, such as fragrance oils or colorants, or when the surfactant is harsh. Again, soaps are harsh surfactants, they aggressively seek out lipids and emulsify them into the solution. This makes soaps effective degreasers, but they are also likely to attack delicate tissues of the eyes. Similarly, Sodium Lauryl Sulfate (SLS) is a very aggressive surfactant that can overstep its mission of attaching to dirt and oils and actually cause irritation to eyes or skin. SLS is often used as the means of establishing the harshness of other surfactants. They are rated as to how they compare in harshness to SLS.

But harshness of a surfactant ingredient alone does not itself determine the irritation potential of a shampoo. Irritation Potential = harshness of surfactants + concentration of those surfactants + contact time. Concentration of surfactants is determined by the specific formulation and by the dilution of the product. Foaming products are highly diluted, so are much less likely to cause irritation than is something straight out of the bottle. Foaming also dilutes other irritants in addition to the surfactants. I strongly urge the use of foaming face cleaners to prevent eye irritation. Any shampoo can be turned into a milder face cleaner by diluting it 10-15:1 and placing it in a foamer. You can buy a foamer or re-purpose one from a foaming dish soap.  The practice of frothing by beating a diluted shampoo or conditioner or milk foamer has recently gained popularity and allows for good application of less product as well as reducing irritation potential.

Contact time is an important part of the irritation equation. The longer an irritating surfactant solution is left in contact with tender eye tissue, the more damage it can do. Left neglected overnight, there can be serious corneal damage. It is vital that bathing staff be diligent in detecting signs of eye irritation and do a 5-minute eye flush on any dog who is squinting or rubbing an eye - even if it means ruining a lovely groom.

Other potentially irritating ingredients in pet shampoos are preservatives and cationic conditioning ingredients, such as cetrimonium chloride.  It is important to keep in mind that ANY shampoo can cause eye irritation to a sensitive individual. As stewards of the animals in our care, groomers must not assume a false confidence in marketing claims of "tearless". 

For more information on tearless shampoos, please read our previous article HERE.

In addition to owning TRANSFORMATION PET CENTER in Tucson, Arizona, BARBARA BIRD is author of the book Beyond Suds & Scent - Understanding Pet Shampoos & Conditioners.  She is also half of The Groom Pod, a weekly podcast for groomers. The Groom Pod can be found on iTunes, Stitcher, Facebook or www.thegroompod.com.