Started experiencing the same reaction I have had in the past to doxycycline, vancomycin, azithromycin, pencillin,
keflex,
and co-trimoxazole.I want to stress this reaction sometimes comes with a faint rash sometimes not at all. The nature of it being rather a burning sensation under the skin which is not visible, there is no hives, blisters sometimes not even a rash at all. The only thing that seems to help during this reaction is a steroid skin cream they gave me one time it works wonders !