What does it mean when your client has green nails? The most common reason is they bumped them, loosened the nail coating, and moisture got trapped, allowing bacteria to thrive and poop. The green stain left behind is a result of the waste from the bacteria and will grow off as the nail grows out. Buffing the stain away will thin the nails out considerably, weakening them, and is not advisable. Once you remove the nail coating, the exposure to the oxygen generally takes care of things. Taking the further step of cleansing the nails will remove the bacteria, leaving only the stain behind, and you can reapply the nail coating and allow the stain to grow out. This is not mold or fungi; however, we also must remain within scope of practice and avoid using a diagnosis.
Knowing it is simply a bacterial infection and stating it are two different things! One way you can phrase it would be “This looks similar to what I have seen as a bacterial infection, which leaves behind a stain that will grow out. We can document it with a photo and reapply your coating to ensure it doesn’t grow and that it is growing off. If you are concerned, we can leave it uncovered so that you may see a dermatologist.”