My chronic scalp foliculitis was gone away after h-pylori triple drug therapy. i was without it first time in years for about 2 months or so. but it is back again. what does this tell about underlying cause of it?

Scalp folliculitis: That is interesting Has you H pylori recurred? ( can do breath test) Would consider assessment by allergist regarding food allergies as that may be what is predisposing to H pylori and causing scalp folliculitis versus scalp eczema

Antibiotic in triple: The antibiotics amoxicillin and clarithromycin in triple therapy helped to eradicate the follicullitis.So if you have recurrent folliculitis you can try one of the two antibiotics- amoxicillin or clarithromycin.