How do vets find fleas on dogs?

Sometimes it's as simple as running my finger against the growth of the hair to look at that skin deep down to see if I can see any. Sometimes I don't see the actual live flea itself, but I can see some evidence that they've been there in terms of what we call flea dirt, which is flea poop. As gross as it sounds, that's what it is, the fecal material of the flea that they leave behind while they're on your pet.

Vets can easily find fleas on dogs if there's a large population, as they are visible to the naked eye. However, if there's a small population of fleas, it might be more difficult to spot the live adult fleas. In this case, vets look for flea dirt, which appears similar to regular dirt but dissolves into a rust or red stain when water is added. This is because flea dirt is made of digested blood and serves as evidence of fleas just like finding a live flea would.