What Are the Signs of an Allergic Reaction to Caffeine?

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  • Written By: Meshell Powell
  • Edited By: Melissa Wiley
  • Last Modified Date: 11 February 2019
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An allergic reaction to caffeine is not always obvious and may be confused with an intolerance or another medical condition. A severe and potentially life-threatening allergic reaction to caffeine is rare and usually involves symptoms such as hives; difficulty breathing; and swelling of the face, lips, or tongue. More common signs of a caffeine allergy may include heart palpitations, muscle twitches, or headaches. Any questions or concerns about a possible allergic reaction to caffeine should be discussed with a doctor or other medical professional.

Heart palpitations and headaches are among the most common signs of an allergic reaction to caffeine. Large doses of caffeine are known to cause heart palpitations, but those who have an allergy may notice this symptom after consuming a small amount. Caffeine is often used to help treat headaches, especially migraines. People who are allergic to caffeine may develop headaches or notice increased pain from an existing headache after consuming caffeine.

Muscle twitches or shakiness, often referred to as jitters, may occur when a person has an allergic reaction to caffeine. Mild jitters sometimes occur when caffeine is consumed in large doses or on an empty stomach, but those with an allergy often experience these symptoms when ingesting any amount of caffeine. Tremors may develop which mimic other medical disorders such as Parkinson's disease. A rash that may or may not itch that develops shortly after consuming caffeine may also indicate the presence of an allergic reaction.


Blurred vision may occur in those who experience an allergic reaction to caffeine. This symptom normally starts within a few minutes of caffeine consumption. In more severe cases, the visual disturbances may be accompanied by hallucinations. Mood changes, such as confusion or agitation, are also commonly experienced by those with an allergy to caffeine. People with severe caffeine allergies may become extremely confused and have trouble focusing on anything or communicating thoughts with others.

In rare cases, an allergic reaction to caffeine can be fatal. A severe allergic reaction known as anaphylaxis can lead to swelling of the face and throat, resulting in an inability to breathe properly. Without an adequate oxygen supply, permanent brain damage or even death can occur within a matter of minutes. Emergency medical care is essential for anyone who exhibits possible symptoms of anaphylaxis. Anyone who has experienced an anaphylactic reaction in the past will usually be prescribed an injectible medication to be carried at all times in the event of a recurrence.



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Post 3

@donasmrs-- A caffeine allergy can show itself in psychological symptoms in addition to physical symptoms. I am allergic to caffeine and the major reaction I develop is depression and anxiety. Caffeine makes me feel detached, upset and moody and it usually takes days for me to get over it.

And the more caffeine, I have, the worse I get. The caffeinated energy drinks are the worst, they turn me into a mental patient.

Post 2

@simrin-- I'm not a doctor so I'm not sure. But I think these are common side effects of caffeine and perhaps a caffeine sensitivity or intolerance. My brother has a caffeine allergy and he has typical allergic reactions like rash, redness and swelling from coffee.

It seems like caffeine allergy is a difficult one to diagnose because caffeine has some serious affects on the body and causes many issues like you experience. It gives energy, but also causes heart palpitations and anxiety, followed by fatigue, mood changes and insomnia. These can also be a sign of caffeine addiction.

The best way to know if you are allergic to caffeine is to see a doctor for an allergy test. It's probably a good idea to stay away from caffeine if you feel so unwell after drinking it.

Post 1

I get an adrenaline rush, jitters, heart palpitations and insomnia when I drink coffee. Am I allergic?

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