Been dealing with scalp folliculitis on and off for years. doxy used to work, now doesn't clear it fully. tried mino and keflex-kept at bay. help?

See a deermatologist: Begin with evaluation by a skin specialist. Meanwhile use a daily shampoo, perhaps with salicylic acid such as T-Sal. Probably need long-term minocycline or doxycycline 50 or 100mg a day for at least a year.

Antibiotic...: ...resistance. Antibiotics often stop working over time; in presence of the antibiotic, bacteria tend to become resistant to it. (Evolution at work!) But it is unlikely minocycline would help if doxy doesn't; these drugs are twins, usually with identical activity against the same bacteria. However, cephalexin is very different. See a doctor, preferably a dermatologist. Good luck!