Brief Answer:
You may be or not be allergic to penicillin. We never know until try it.

Detailed Answer:
Hello,

Thank you for using HCM to post your question.
I read carefully your question and I understand your concern.

Penicillin allergy is very specific, like any other allergy. If you are allergic to something, it doesn't mean that you will be allergic to something else. In penicillin case though, there is a slight chance that you will be allergic to the group of cefalosporines (the names that you mentioned above), that chance is 0.5% I think.

You may be allergic to cefalosporines and not be allergic to penicillin.
You may also be allergic to some of the cefalosporines but not to others.

So to summarize, my recommendations are:
- Even if you may not be allergic to penicillin, dont use it outside of hospital just in case, so you are under medical suppervision.
- You are not allergic to Zinnat, but you are allergic to the other ones that you have had an allergic reaction from, so avoid those.
- Reaction may be different from mild rash, to life threatening.
- With the time a person that has been allergic to something, may be more allergic or not be anymore allergic. So thats why we prefer to avoid medicines that a person has been once allergic, because you never know.

Hope this is helpful. Let me know if you need more clarifications. Otherwise please kindly close and rate the answer.

Regards

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