I'm returning home to my outdoor cats. The problem is that they were not given flea medication during this time. This is what I'll do as soon as I'm back and see them. Between the time it takes for the medication to work and kill the fleas, how should I interact with the cats? Should I wash my clothes after? How? And is washing my hands enough to prevent me from getting them?
While it is possible for a cat flea to bite you, they usually don't do it. Cat fleas don't survive for long feeding on humans, so you don't need to worry about an infestation.
Just vacuum your home regularly.. the medication on your cats will take care of them eventually.
Reference: Connecticut Agricultural Experiment Station
Fleas are pests, but they do not infest you or your clothes. What they can do is bite, and that can be a bother. While not particularly painful, some people will exhibit a minor inflammatory response (slight swelling and reddening at bite site), they can itch, and leave unsightly little bite marks until healed.
I recommend the use of a veterinarian-approved neurotoxin usually administered monthly by breaking the seal on a small liquid-filled vial and pushing the liquid onto the cat's skin between hairs on the back of their neck. Once it reaches the cats skin there, it actually spreads to cover the skin's entire surface on the cat. A good quality neurotoxin will kill fleas in all stages of their life cycle. The other most likely candidate for a flea poison would be those places where the cat usually sleeps. There you would find a spray that you may use safely on furniture or fabric.
Fleas are hard-bodied (very difficult to kill manually) and they jump. They are easy to spot if there are many of them.
Of much more concern are ticks that the cat can carry in from fields and grasses outside - including deer ticks which have been known to carry and infect humans with Lyme's disease. The same neurotoxin mentioned above kills ticks as well.
I have had from one to four cats at any given time throughout my life. They are fine companions and fleas can be managed with regular care.