Is it safe to use sulpha products if one is allergic?

Q: Is behentrimonium methosulfate, condroitin sulfate or glucosamine sulfate the same as sulpha? My husband purchased a topical joint pain formula containing these products, but I am cautious about using them. My sister and I are allergic to sulpha and both of us recently had reactions to OTC products. I broke out after using a lotion with MSM in it and so did she after using a dandruff shampoo with sulpho O in it. Please advise.

A:All medicines, both for internal and external use, that have a sulpha (or sulfa) in their chemical name contain sulphur and hence must not be used by people allergic to this agent.