What happens if you are allergic to the anesthesia drugs you receive? 

This is one of the most common questions my colleagues and I are asked. 

Allergy denotes a response by the body's immune system to a `foreign` substance. Usually the substance (or `allergen`) is something not ordinarily harmful to the body, such as penicillin. 

Severe allergic reactions during anesthesia are fortunately rare, occurring only once in every 5,000 to 25,000 anesthetics. Unfortunately, these reactions can sometimes be fatal; about a 3% (3 in 100) mortality has been documented. 

The most severe form of allergic reaction is known as anaphylaxis. During an anaphylactic reaction the patient may experience difficulty breathing, as air passages close up. Swelling of the face and mouth can occur, and a reddish skin rash is also sometimes seen. The heart and blood vessels are severely affected, and this is the hallmark of the condition: the heart rate increases and blood pressure can drop to dangerously low levels. 

Anaphylaxis during general (asleep) anesthesia presents in a similar way but there are three unique features. 

First, the patient who is asleep cannot tell us about light-headedness or breathlessness which might be early warning symptoms. 

Second, during a typical general anesthetic, many drugs are given, and it is hardly ever clear which of these drugs have caused the reaction. 

Third, during anesthesia there are many other potential causes for the blood pressure to drop or the air passages to close off. A diagnosis of anaphylaxis is therefore not always easy to establish. 

Although severe allergic reactions may be a little more difficult to detect under anesthesia, a patient having an anaphylactic reaction under anesthesia is actually in a very good place to get promptly treated. All the necessary equipment and medication to successfully treat the reaction is at hand in the operating room. Anesthesiologists are experts in the treatment of such reactions. Treatment may include insertion of a breathing tube, administration of intravenous fluids, and a variety of drugs, the most important of which is epinephrine (adrenaline). Early and appropriate treatment is almost always successful. 

It is worth noting that drugs are not the only cause of allergic reactions. For example, one important non-drug cause of anaphylaxis is allergy to natural rubber (`latex`). Reactions to latex are a special problem during anesthesia as surgical gloves are usually made of this material. 

Two final notes about allergy. First, many allergic reactions are not life-threatening, resulting only in a transient skin rash or such symptoms as nausea and vomiting. Secondly, many drug reactions are not true allergies, representing only an increased sensitivity to common side-effects of the medication. 

When I get local or general anesthesia, I get an icy cold feeling in my chest for several minutes like I downed a glass of ice water. I am 40 years old and have borderline HBP which I take a low dose of medication. Is this an allergy to anesthesia? 

I am afraid I've never encountered the reaction you describe so I cannot offer an explanation. It certainly doesn't sound like an allergic reaction. 

I recently went to the dentist to get a tooth filled and was given 2 vials of carbocaine. I was given carbocaine because my body cannot handle epinephrine. I have a rapid heart beat and it tends to aggravate it. An hour after being injected with the Carbocaine my whole lip and cheek swelled up like a balloon. My dentist and my doctor are perplexed as the cause of this reaction. Have you heard of anyone else having this type of reaction to Carbocaine? 

Carbocaine is mepivacaine, a local anesthetic of the "amide" group. Its relatives include lidocaine and bupivacaine. Epinephrine is added to local anesthetics to prolong their effect. Mepivacaine is sometimes used in patients who cannot tolerate epinephrine because it has a longer duration of action than lidocaine. 

It sounds like you may have had an allergic reaction. The reaction could be due to the mepivacaine, to some additive in the mepivacaine, or to something else entirely. Mepivacaine does not usually contain additives, but you should check with your dentist on that. Allergy to mepivacaine itself is quite rare but does occur. You can be checked for allergy with skin tests administered by an allergist (a specialist in allergy). 

One final possibility is that you experienced a reaction the gloves used by your dentist (usually latex) or by something else she put in your mouth. The fact that the swelling was only on the side of the injection suggests that latex allergy was not the culprit. 

An alternative to mepivacaine is a drug of the same class called bupivacaine. Your dentist might consider bupivacaine for future dental procedures. Bupivacaineﾠis not known to cross-react with mepivacaine. There are also local anesthetics of an entirely different class, called esters, which could be used. 

I think it is worth following this up with an allergist because the type of reaction you describe could be associated with more serious life-threatening reactions, which luckily did not occur in this case. 

I had a colonoscopy yesterday, which involved mild intravenous anesthesia, enough to put me to sleep during the procedure, but immediately afterward I was awake and alert. However, I soon began having hay fever-like symptoms such as sneezing, watery eyes, and runny nose that lasted throughout the day and into the next. I have no allergies that I`m aware of (including latex), and I`ve had this procedure before, as well as two hernia repairs with intravenous anesthesia, with no such effects. Is it possible that I am reacting to something in the anesthetic? 

It seems unlikely that your symptoms are due to the anesthetic. During your colonoscopy you were probably given propofol, fentanyl, midazolam or some combination of those or similar agents. Allergy to these drugs is rare, and would not usually present with hay fever-type symptoms, but rather with a rash, low blood pressure or breathing problems. I think its more likely that you reacted to something that was inhaled. The most obvious candidate is latex, which is often present in measurable concentrations in the air of procedure and operating rooms, and is derived from rubber gloves and other medical items. You probably had an oxygen mask on your face during the colonoscopy so I wonder whether there was something (possibly latex) in or on the mask to which you reacted. You sound fairly certain that you do not have latex allergy (why?) and I can't think of any other inhaled allergen likely to be present in a clinic or hospital setting. Latex allergy is relatively common in individuals who use rubber gloves frequently (e.g. healthcare workers) and causes hay-fever symptoms and a rash, progressing sometimes to severe problems with blood pressure and breathing. Have you ever had hay fever before? Perhaps it's just a coincidence that you had your colonoscopy and the hay fever on the same day! 

How can I find out the types of Anesthesias I am allergic to and what kind of test need to be made? 

ﾠJudging by the way you have posed your question, I am guessing that you may previously have had a reaction to an anesthetic. In that case, I need a little more information about the type of reaction that occurred and the circumstances. If you have not had a problem, and are not known to have any other type of allergy, it is most unlikely that you will have a serious reaction to any of the commonly used anesthetic agents. Testing for allergy to anesthetic drugs is quite specialized and should be undertaken by an experienced allergist. The tests involve either blood analysis or application of small amounts of the suspected allergen to the skin.