About 12 or 13 years ago I had allergy testing via the skin prick method. Among the things I was found to be allergic to was tea. I was an avid tea drinker and I tried to avoid the identified allergens. After a week, I snuck a glass of tea and found that it was triggering the blinding headaches I had been having. I stayed away from tea for 10 years. After 10 years the desire was so bad that I snuck a glass of tea again. No apparent symptoms this time. I figured that I had gotten over the allergy and started drinking tea again. In the last two or three years, I got to where I was drinking at least a half gallon a day. Unsweetened, no sugar or artificial sweeteners, no lemon or other additives. The past few weeks I've had some weird body issues. Clamminess, shakiness, nausea, feeling drained. It felt different than a low blood sugar reaction and testing revealed normal glucose levels. Through process of elimination I found it was being triggered by drinking a glass of tea. Caffeine has never really affected me, I'm the type that can drink a cup of coffee right before bed. But I will admit I don't often ingest caffeine through coffee or medicines. Are the symptoms of clamminess, shakiness, feeling drained and nausea some weird food allergy symptoms indicating the tea allergy has come back? Or is it more likely a newfound sensitivity to caffeine?