Allergy & immunology · Cincinnati
Anaphylaxis, food allergy and drug allergy
A severe allergic reaction raises urgent questions: what caused it, how to prevent another, and whether a food or medicine label is accurate. Dr. David I. Bernstein evaluates patients after anaphylaxis and with suspected food and drug allergies.
What anaphylaxis is
Anaphylaxis is a serious allergic reaction that comes on quickly and affects more than one part of the body. Common triggers are foods, medicines and insect stings; sometimes no cause is found.
Epinephrine is the first treatment for anaphylaxis. Dr. Bernstein was lead author of a 2025 safety review concluding that the benefits of epinephrine for anaphylaxis outweigh its potential harms.
Warning signs
- Hives, flushing or swelling
- Trouble breathing, wheezing or throat tightness
- Vomiting, cramping or diarrhea
- Dizziness, fainting or a drop in blood pressure
- Symptoms after a food, medicine or sting
After a severe reaction
An evaluation aims to confirm the cause, prevent another reaction and remove allergy labels that are not accurate.
Reconstruct the reaction
Timing, foods, medicines, activities and symptoms, plus any emergency records.
Targeted testing
Skin or blood tests chosen for the suspected trigger, interpreted alongside the history.
Supervised challenge
When testing is unclear, a carefully monitored dose of the food or medicine can confirm or rule out allergy.
Action plan
An emergency plan, epinephrine when appropriate, and clear guidance on what is safe.
Food and drug allergy
Many people avoid foods or medicines because of a reaction years ago. A food intolerance is not the same as a food allergy, and most people who report a penicillin allergy are not truly allergic when tested. An accurate diagnosis widens diet and treatment choices.
Drug allergy evaluation can include skin testing and supervised oral challenges, and when a needed medicine causes a true allergy, desensitization may allow it to be taken safely.
A visit may help if
- You have had a reaction to a food, medicine or sting
- You avoid foods based on a test result alone
- You have a penicillin or other antibiotic allergy label
- You need a medicine you are thought to be allergic to
- You have had anaphylaxis without a known cause
Common questions
Do I really have a penicillin allergy?
About 10% of Americans report a penicillin allergy, but clinically significant allergy is found in under 5%. Testing can often remove the label safely.
Is a positive food allergy test enough to diagnose food allergy?
Not on its own. Many people with positive tests can eat the food without symptoms. Results must be interpreted with the history, and sometimes confirmed with a supervised challenge.
When should I use epinephrine?
Follow your written action plan. In general, epinephrine should be given promptly for signs of anaphylaxis, followed by a call to 911.
Does Dr. Bernstein review anaphylaxis cases for attorneys?
Yes. He provides independent medical-legal review of anaphylaxis and allergic reactions to foods and drugs. See the expert witness page.
Dr. Bernstein’s work
Dr. Bernstein co-authored the 2010 national practice parameter on anaphylaxis and has published on epinephrine treatment, including recent studies of epinephrine nasal spray.
Selected publications
- Bernstein DI, Blaiss M, Dellon ES, Rance K. Benefits of epinephrine for anaphylaxis outweigh potential harm: a safety review. J Allergy Clin Immunol Pract. 2025. PubMed · DOI
- Lieberman P, Nicklas RA, Oppenheimer J, et al. The diagnosis and management of anaphylaxis practice parameter: 2010 update. J Allergy Clin Immunol. 2010. PubMed · DOI
- Greenhawt M, Lieberman J, Blaiss M, Bernstein DI, et al. Pharmacokinetic and pharmacodynamic profile of epinephrine nasal spray versus intramuscular epinephrine autoinjector. J Allergy Clin Immunol Pract. 2024. PubMed · DOI
Had a serious allergic reaction?
Request a consultation. For an emergency, call 911.