Unlike Neosporin, a triple antibiotic ointment, Polysporin is a double antibiotic containing ingredients bacitracin and polymyxin B but lacks neomycin, the third ingredient in Neosporin.  When the cut or injury is deep, it’s more prone to become sensitized to an allergen, so even if the patient isn’t allergic to neomycin previously, an allergy can develop late in life after prolonged exposure to Neosporin.  When applying ointment to the private area, it’s best to consult a doctor before self-treating it.