Anaphylactic Shock After Botox

However in medicine, we never rule any possibility out.  Never-the-less, it is much more likely that it was the antibiotic directly that you are allergic to and not some unheard of interaction between the BOTOX treatment three weeks before and the subsequent antibiotic treatment.  Speak directly to your injecting physician and if you are still not comfortable, seek alternatives to botulinum toxin treatment.  These are generally elective services.  It is worth noting that Allergan, the maker of BOTOX does warn that it is possible to have an anaphylatic reaction to BOTOX.  Given your history, you might consider being tested by an allergist if you intend to seek BOTOX treatments in the future.

the botox you had certainly did not cause anaphylaxis if it was taken three weeks before the onset of the anaphlaxis.  If it was taken at the same time as the antibiotic, it was probably the antibiotic that caused the problem.  It is a very common misconception to think that one could not be allergic to a drug if they had it before, without any problem.  Interestingly, one is rarely ever allergic to something the first time they take it or are exposed to it.  Your immune system must develop a sensitization to the chemical which occurs from the first exposure(s) you had and then, after some time, and at any subsequent exposure to the drug, you can then develop an allergic reaction. It was probably the trimethoprim, not the botox. Often, the trimethoprim is given in a combination pill with sulfamethoxazole, known as Bactrim or Septra, and the sulfa molecule is often a culprit of the allergy, if an allergic reaction occurs.

The fact that you have had these antibiotics before means your body has already been sensitized to them and an allergic reaction would happen much more quickly.

It is also possible to become allergic to something you were not allergic to previously.