I admit to being a coffee addict. Not only must I have a cup or two of coffee every morning, I also enjoy a cup of coffee in the mid to late afternoon. The caffeine boost helps me get started for the day, and the extra jolt in the afternoon helps me to have a productive evening after a long day at work. I’m not sure what I’d do if I couldn’t have my daily coffee fix – like a lot of people in the world, I’d survive, but life would be a lot less enjoyable – and harder to deal with.

Coffee is an extremely popular drink, not only in the United States but around the world, particularly in Europe. The popularity of coffee has grown over the past few decades, likely at least in part due to the success of Starbucks Coffee Company. In the past, coffee was consumed mostly in relationship to meals; people now drink coffee during all times of the day, with or without food, even as a dessert or iced beverage. All told, the world consumes 1.4 billion cups of coffee a day, with the highest consumption being in Europe. With a large amount of coffee being consumed, it would seem that many people would be experiencing allergic reactions as a result of drinking coffee.

How Common is Coffee Allergy?

Surprisingly, there is little to no information in the medical literature regarding allergic reactions to drinking coffee. Coffee allergy is well described in terms of an occupational allergy, however.

The first reports of occupational allergy to coffee date back to the 1950’s and 1960’s, when workers at coffee production plants began to experience symptoms of nasal allergies and asthma with exposure to raw (green) coffee beans and roasted coffee dust. This fact suggested that coffee allergens survived the roasting process, and therefore drinking coffee would be expected to cause allergic reactions in certain people.

Unfortunately, the major coffee allergen was not characterized until recent in a study published in 2012 by researchers from Germany.

A group of 17 coffee plant workers who complained of nasal allergies as a result of exposure to coffee dust was studied. None of these people experienced any reaction with drinking coffee. Currently available commercial allergy blood tests detected the presence of IgE (allergic) antibodies in only 2 of the workers. The researchers were able to identify the major coffee allergen, called Cof a 1, and developed a method to test for this allergen with a blood test. This testing method allowed for the identification of more workers with an occupational allergy to coffee dust.

It is unclear why there aren’t more reports in the medical literature about allergic reactions to drinking coffee, as it would certainly seem possible. Most people who experience symptoms after drinking coffee, such as headaches, rapid heart rate, gastrointestinal upset (such as nausea or diarrhea), jitteriness and insomnia are having either a non-allergic food intolerance or pharmacologic side effects from caffeine contained within the coffee.

One report from Italy, published in 2008, described a father and daughter who experienced presumed coffee allergy after contracting a parasitic infection. The authors theorize that the parasite damaged the intestine and allowed the development of coffee allergy to occur. Both father and daughter showed evidence of specific IgE to coffee with positive blood testing and skin testing, and symptoms of hives and diarrhea occurred when drinking coffee and resolved when coffee was avoided.

Interesting, there are a number of reports of people being allergic to caffeine, with symptoms ranging from hives to severe anaphylaxis. Therefore, any patient who is considered as having a coffee allergy should be considered as possibly having an allergy to caffeine instead. A person with allergy symptoms after drinking decaffeinated coffee would likely be allergic to coffee, while a person with allergy symptoms after drinking other caffeinated beverages (such as cola, tea or chocolate) would more likely have a caffeine allergy.

So, next time you’re at the local coffee shop, get the large size coffee. You’re not likely to become allergic to it (thought it is always wise to get an allergy test to see if you have an allergy to anything added into that coffee).