Anesthetic Testing: What It Is and When It Is Done

A conversation about allergy to pain relief usually begins with anxiety: a person remembers swelling, a rash, or faintness after an injection at the dentist and fears a repeat. Meanwhile, local anesthetics are used very widely, and serious side effects from them are rare. Let us clarify what exactly anesthetic tests check and where the boundary lies between true allergy and other reactions.

What anesthetic tests are and why they are needed

A local anesthetic is a medicine that numbs an area of the body: the person is conscious but does not feel pain during the procedure. It works by interrupting the transmission of pain signals along nerves to the brain.

Whether allergy to local anesthetics occurs: lidocaine, septanest, and others

Drug allergy is an immune response to a medication: on first contact the body may produce antibodies, and on repeat contact it may react with symptoms. Among the common causes of such reactions are penicillin antibiotics, anticonvulsants, animal-derived insulin, and iodine-containing substances. Local anesthetics are divided into amino-amide and amino-ester compounds. At the same time, most unpleasant effects of medications are not associated with the formation of IgE antibodies. For most medications there are no reliable skin or laboratory tests, so the decision about which pain relief is permissible is made by the doctor.

How allergy tests for anesthetics are performed

Skin testing helps identify allergy to penicillin-type medications. There are no good skin or laboratory tests for other drug allergies. If a person had allergy-like symptoms after a medication or contrast agent during an X-ray, the doctor often regards this as evidence of a reaction and does not order additional tests.

What the results of anesthetic tests mean

With confirmed allergy, the rule becomes avoiding the culprit medication and similar agents. Sometimes the doctor considers desensitization — administering very small doses first with a gradual increase, but only when there is no alternative and only by an allergist. Repeating such regimens on one's own is unacceptable.

How allergy to an anesthetic differs from other reactions

Many people confuse allergy with an ordinary side effect: nausea, dizziness, blurred vision, muscle tremor, or tingling. After an injection, slight soreness, a bruise, or a burning sensation are possible while the anesthesia wears off. Such phenomena usually resolve within minutes or hours. Allergic symptoms are hives, itching of the skin or eyes, rash, swelling of the lips, tongue, or face, and wheezing. A severe reaction, anaphylaxis, is rare and usually develops in the first minutes after administration.

When to consult an allergist

The reason for a consultation is any reaction to pain relief in the past, especially if it was not only local. Any drug allergies must be reported to all doctors, including dentists and hospital staff. Before a procedure, report all known allergies to medications and other substances. If after an anesthetic there are troubling symptoms that do not resolve, a medical assessment is needed.

Pain relief itself is not a reason to call an ambulance; 103 or 112 — if after an anesthetic there is difficulty breathing, a hoarse voice, swelling involving the lips, tongue, or face, hives on the body, nausea and vomiting, abdominal pain, dizziness, fainting, a feeling of heart palpitations, or confusion.

• Skin testing is informative mainly for penicillin medications.
• For most other medications there are no reliable skin or laboratory tests.
• An allergy-like reaction after a medication or contrast agent often itself serves as the basis for concluding there is an allergy.
• Desensitization is performed only by an allergist and only when there is no alternative medication.

This material is for reference: it explains the essence of the tests and the limits of their capabilities, but does not replace consultation with a doctor who will assess your specific situation.

This content is for reference and does not replace a doctor's consultation. Medical disclaimer