I am a allergic keflex (it results in anaphylaxis) but was just prescribed augment in for a possible lymphangitis infection is it safe to take it?

Don't take it: There are similarities between Keflex and augmentin, (amoxicillin and clavulanate) but they're not the same. For milder reactions such as rash, someone allergic to one may not be allergic to the other. But for severe reactions such as true anaphylaxis, the risk of a similar reaction to Augmentin (amoxicillin and clavulanate) is too great.

Probably: There is very little cross-reactivity between the penicillins and cephalosporins. On the other hand if you have had an anaphylactic reaction to one it makes sense to either avoid the other or to take the first dose in a location in which resuscitation can be effected should you be the victim of the rare reaction. People allergic to one medication often are predisposed to react to others.

Avoid: Since you had a severe reaction, i wouldn't chance it since there can be some cross reaction.