The symptoms of crabs should take effect on you within a few hours...If you go to the health and disease website & research it will give you the exact amount of time but being in nursing I would say around 3 hours or so that give the eggs time to hatch in the area that they are in and form into crabs..Crabs are like lice so be aware of were you are cause they can crawl away from the body and attach to someone else body where there is hair.
