Antihistamines can be roughly divided into topical and systemic. There is only one topical antihistamine, Astelin, which is a nasal spray has proven beneficial to some. It can still be mildly sedating and has a bad taste.Systemic antihistamines can be roughly divided into sedating and non-sedating types. Interestingly, the sedating ones are over-the-counter, while the safer non-sedating antihistamines are generally prescription. This is all economically-based.