What's the matter with red pimples and itching on the back?

There are several possibilities for red pimples and itching on the back: the first possibility is papular urticaria, mainly due to insect bites or allergic reactions caused by contact with insect and parasite body fluids. Treatment can be oral epinastine hydrochloride capsules 1 time/day, 2 capsules/time, if itching is severe, chlorpheniramine maleate injection 1 time/day, 1ml/time, and external application of desonide ointment 1:1 mixed butoxyacetic acid ointment for treatment. The second kind may be folliculitis, its itch is mostly caused by inflammation infection, so can oral minocycline hydrochloride capsule 50mg, 2 times/day, or azithromycin tablets 0.5 g, 1 time/day, continuous oral 3 days to stop drug, topical clindamycin phosphate gel for treatment.