It's clear reading the posts here that there are many causes as well as many potential rememdies to the problem. Some work for some people whilst not for others. The only time in 12 years that my folliculitis has gone away has been as a side effect of taking antibiotics for sinus or chest infections (1 course in every 1 or 2 years). The problem has gone for up to 4 months at a time but has always returned. I have only ever had antibiotics specifically for this problem on one occasion. A 1 month course. It took the problem away after a week but it returned after 3 weeks, I. E. before I'd even finished taking the anitbiotics.
I have recently taken a stronger antibiotic for a bad sinus infection that I had had for 4 weeks. Sure enough the folliculitis has gone away and I've been free of it for a month now. It remains to be seen how long it will be gone for this time.
One thing is for sure, the fact that it goes when I take antibiotics proves that my problem is related to a bacteria not a fungus or diet etc. That will not be the case for everyone.
I just have to find a permanent cure now, although I have no doubt that I will have to take antibiotics again for a sinus or chest infection, I have no deisre to take them for folliculitis.