Pubic lice does not go to the air in your head.

Even if you scooped head lice and pubic lice and put on your tummy they would make way to where they came from.

Unfortunately shaving will not eradicate the problem. Medicated shampoo will.

This was my experience with treatment however the lice did end up in my head hair, which was just awful.

OP, it sounds like you're becoming re infected either from there being un hatched eggs going through their life cycle or from your regular clients. You need to fumigate...Use the treatments as instructed but also either throw away, or put all of your towels and bedding on a boil wash (at least 60 degrees, preferably 90) clothing and anything else you've been in contact with over the past few months and anything that can't be washed is to be put into a sealed plastic bag for 72 hours (this kills any stray mites/eggs) As already said vacuum your mattress/turn it over and I would also use shake on insecticide on carpets before vacuuming your whole house. Then somehow you need to tell your regulars that they need treating too, it won't be easy but its the only way to stop this vicious circle. Good luck 

A conditioner is really good when treating. Helps the runners and eggs slide out of the hair. You have to treat everyone in the house though, and like pubic lice, bedding and towels have to be washed. You also have to repeat every couple of days. Even if you use chemicals, you have to retreat about a week later to get rid fully. Something a lot of people fail to do and wonder why they have loads

To stop nits, tea-tree products are a good deterrent. After my kids getting nits a couple of times as kids, started using tea-tree on them, and although we were constantly getting letters informing us the school had a nit problem, mine were always free.