Folliculitis is a general term that quite literally means inflammation of one or more hair follicles. In the purest derivation of the word, it doesn't imply any etiology of the inflammation, however when it is used by most physicians it is due to infectious agents. However, there are multiple different causes of folliculitis, both infectious and non-infectious. Infectious causes of folliculitis can be further sub-divided into bacterial, fungal, and viral. The most common causes of bacterial folliculitis are Staphylococcus aureus, and Pseudomonas aeruginosa (etiologic agent in "hot-tub" folliculitis).
The thought is that there is some insult to the follicles that allows the skins normal flora (bacterial flora that is normal on the skin) to enter the follicle and cause a local infection. This is why folliculitis is characterized by a red rash, with small pustules/pimples that are centered on hair follicles. It is generally very itchy/sore, it may be associated with crusting, and it can spread to other hair-bearing areas without treatment. As I mentioned earlier however, there are non-infectious causes of folliculitis, and the list of dermatologic conditions that cause rash and folliculitis is well beyond the scope of this forum. For this reason, most physicians will attempt to treat an isolated folliculitis with anti-biotics or anti-fungals prior to a referral to a dermatologist
for further work-up. I can;t tell you for sure if you have folliculitis without being able to examine you, but it is a relatively common problem that your primary care physician
should be able to diagnose and treat. I hope this helps.