Macrolide hypersensitivity is a rarely reported event. Carmine dye has become increasingly important as a provocative agent for allergic reactions.
Carmine, also called Crimson Lake, Cochineal, Natural Red 4, C.I. 75470, or E120, is a pigment of a bright red color obtained from the carminic acid produced by some scale insects ("beetle juice"), such as the cochineal and the Polish cochineal, and is used as a general term for a particularly deep red color.
Carminic acid. Image source: Wikipedia, public domain.
This is a case report of a woman with documented carmine hypersensitivity, who reported anaphylaxis 90 minutes after ingestion of a generic azithromycin. She had not problems with the brand name Zithromax taken on previous occasions.
The cause of anaphylaxis was an allergy to the carmine dye in the tablet's coating rather than to the antibiotic (azithromycin).
Azithromycin. Image source: Wikipedia, public domain.
Seven extracts were prepared including carmine dye, crushed dried female cochineal insects, crushed tablets of Zithromax (Pfizer Inc.) and generic azithromycin (Teva Pharmaceuticals), and the crushed colored coatings from both tablets. The exctracs were dissolved in normal saline, and then applied as a skin-prick test and read at 30 minutes.
The skin-prick skin test results were 4+ to histamine and carmine dye, but negative to cochineal insect extract, Pfizer crushed tablets, and negative control. The patient was 1+ to the Teva crushed tablet, but was 4+ to the Teva brand coating and negative to the Pfizer brand coating, which did not contain carmine.
The patient subsequently ingested Pfizer Zithromax without any sequelae.
According to the authors, this is the first reported case of carmine anaphylaxis attributed to carmine-containing medication.
Carmine hypersensitivity masquerading as azithromycin hypersensitivity. Greenhawt, Matthew1; McMorris, Marc; Baldwin, James. Allergy and Asthma Proceedings, Volume 30, Number 1, January/February 2009 , pp. 95-101(7).
Testing for red coloring agents added to foods - AAAAI Ask the Expert, 2011.
The data suggests an extremely rare occurrence of azithromycin allergy http://goo.gl/6fZHL
Q&A: How can I find out which ingredients are in a medication? http://goo.gl/UQWQf
Carmine, from Wikipedia, the free encyclopedia. The best price for azithromycin is at Costco: 18 tablets for $18. Drug provocation tests remain the key to diagnosing macrolide allergy http://goo.gl/WM5rj
"Starbucks admits Strawberry Frappuccino contains crushed bugs" - carmine is natural alternative to artificial dyes http://goo.gl/XXIhW
The Fascinating Story of How Tropical Insects Were the Best Choice to Color Your Starbucks Coffee (cochineal red) http://goo.gl/ecZmL
Image source: Variations on a common tablet design, which can be told apart by both color and shape. Wikipedia, Ragesoss, Creative Commons Attribution ShareAlike 3.0 License.
@AllergyNet: For me, x2/25 yrs, x1 in sausage x1 in chocolate RT @Allergy: Carmine allergy masquerading as azithromycin allergy http://goo.gl/gST6h
@AllergyNet: Macrolide antibiotic allergy: Which tests are really useful? http://j.mp/jAr3zV Bottom line: NONE (except challenge) Full PDF
Dr. Ellis @DrAnneElli: Have seen this as well - great summary and work up plan for Carmine Allergy.
David Fischer, MD @IgECPD4: Once saw a pt with reaction to strawberry yogurt. Negative to strawberry and milk but +ve to carmine dye