Can I use Botox again after my allergy test came back inconclusive? I broke out in hives a year ago after Botox and Dysport.

It would be worth further investigation before having another Botox treatment. Contact Allergan and speak to a representative who may be able to shed more light on the topic. Best, 

paquita123,True allergy to botulinum toxin (Botox, Dysport, etc.) can occur, but is not common. Inconclusive allergy testing, ay mean that you are allergic to a preservative in the diluent saline (usually benzalkonium chloride, or benzyl alcohol).  At one time it was recommended to use preservative-free saline to reconstitute and prepare Botox for injection, but that recommendation was suspended 8-10 years ago.  Skin testing of saline solution preservatives may help. Benzalkonium chloride is found in eye drops, as well, and fairly frequently causes allergies.  Discuss this with the allergist, as they may not be familiar with how the cosmetic Botox is prepped for injection, so they may not have tested for the agents in the diluent saline.  If you are allergic to a component of the saline solution, and not the Botox, it can be mixed with preservative-free saline.  I hope that this helps.Best wishes,     Tom DeWire, MD, FACS     Richmond, VA    

While true reactions to Dysport and Botox are exceptionally rare, they do exist. If your test came back as inconclusive for all 3 things, then it's hard to say. CAN you have another treatment? Yes. SHOULD you? Sometimes we have to remember that these treatments are cosmetic and if you are going through such large efforts to find out if it's ok, maybe it's just not the right thing for you to pursue it again. While I do agree with much of Dr. Oppenheimer's posting, I will tell you that about a year ago, the regular form of saline we all use to make Botox an injectable was unavailable so we all had to use unpreserved saline - and it HURT many patients and they said it made the treatment very, very painful. So while what he states is true as far as testing, the use of unpreserved saline will make your treatment more painful, and this is something that again, may not actually be the culprit.... "This answer has been solicited without seeing this patient and
cannot be held as true medical advice, but only opinion. Seek in-person
treatment with a trained medical professional for appropriate care."

Ask your allergist to test you for Benzyl Alcohol. If a dermatologist is performing the Botox/Dysport injections, you can ask them to patch test you to this ingredient. It is included in a number of topical agents. This is a preservative found in the preserved saline which the majority of physicians use to dilute Botox and Dysport. There are a fair number of patients who are allergic to this material.   Very few physicians follow Allergan's recommended guidelines to use unpreserved saline. The rationale for the use of unpreserved saline is that this solution which was used when Botox underwent its original testing for FDA approval. Allergan did not want a confounding element, Benzyl Alcohol, in its testing. The FDA requires drug companies to list the exact formulation in the Package Insert ( PI) which was used during its trials. Sure, Allergan could spend millions of dollars by performing trials with preserved saline, but since 99% of doctors  ignore this part of the Package Insert, why would they?  A few years ago, I detected that one of my patients was allergic to Benzyl Alcohol. She would develop a strange rash, well away from where I had injected Botox. It was nearly impossible for me to find non-preserved saline. None of the local pharmacies carried it. I had to resort to purchasing it from one of the hospitals instead. If my colleagues were using unpreserved saline on a regular basis, logically it should not have been so difficult to obtain.     Bottom line: you should check to see if you are allergic to the saline being used to reconstitute Botox/Dysport. If not, be sure to inform your physician that you took a sleeping pill. You might be allergic to that.    If it still seems like it still might be Botox/Dysport, I would not take any chances at all.  Urticarial reactions ( hives) are nothing to mess around with, especially if you are receiving injections. They can be fatal if anaphylaxis develops. So I would tread very carefully. .