Caffeine is commonly found in coffee, soda and energy drinks to help stimulate the mind and promote awareness. Although caffeine may affect your body in various ways, especially if you drink too much, some people are actually allergic to the substance. The difference between common side effects of caffeine and an allergic reaction is the involvement of the immune system. If you have a genuine allergy to caffeine, your immune system overreacts to the substance as if it is dangerous. Talk with an allergist to determine the cause of your symptoms.
Allergic reactions cause inflammation to occur in soft tissue throughout the body. During an allergic reaction the body produces a chemical called histamine that results in inflammation the lungs. As the airways swell, you can become short of breathe, begin to wheeze andcough and develop chest tightness. Asthmatic reactions to caffeine can range from minor to severe. If you cannot breathe, call for emergency medical care immediately.
As histamine is released in the sinus cavity, you will develop nasal congestion, a runny nose and postnasal drip. Nasal congestion will cause pressure to build up throughout the head, which will lead to sinus headaches and facial tenderness. Sinus congestion is the result of inflammation and swelling in the sinus cavities. The swollen nasal passages trap excess mucus in the sinuses; if not treated, this can lead to a sinus infection. The most effective treatment for sinus reactions is to take an antihistamine and decongestant to alleviate sinus pressure and pain.
Your digestive system can react within a few minutes of ingesting caffeine. Swelling in the lining of your intestines will cause nausea, vomiting, diarrhea, stomach pain, cramping, gas and bloating. Most digestive symptoms do not last long because they subside once the allergen is eliminated from the body. If you continue to vomit for more than one day or have diarrhea for more than three days, call your doctor. Blood in your stool or vomit is an alarming symptom that will require further evaluation.
As with any chemical allergic reaction there is a risk of developing a severe allergic reaction called anaphylaxis. Anaphylaxis is a rare reaction in which your entire body experiences a reaction, causing the body to experience a state of shock. Common symptoms include facial swelling, throat swelling, a rapid heart rate, a sudden drop in blood pressure, a metallic taste in your mouth, chest pain and hives.