Arguably my most severe allergy and based on symptoms and testing (positive skin prick test) it is likely an IgE and non-IgE mixed allergy.
Unlike “common sense”, in my case, the IgE component (“true” allergy in its narrow definition) is the mildest symptom (immediate local hives) of the bunch.
After the hives appear, in thirty minutes or so severe abdominal pain, black out, forceful vomiting and diarrhea start and usually resolve in two hours (See “A Case of Adult FPIES”, “FPIES Pain Level”).
I may have had milk issues my whole life, yet didn’t know it, and my body wasn’t given a chance to forget and outgrow the allergy. And things gradually got worse. Starting with supplemental formula, I had milk nearly everyday of my life since birth and so had no chance to know how my body felt without it. Red flags? Always tended toward diarrhea. Urgency after having milk. Addicted to milk.
Possibly a case of undiagonosed/ unresolved chronic FPIES, which got dramatically worse since drug anaphylaxis episode in early teens.
The one time I tried baked milk I had immediate local hives and slight loose stools, but other more severe symptoms (shock, vomiting) did not occur. Later I learned baked milk (along with all other forms or dairy) should be avoided with FPIES.
I had mild ongoing symptoms with butter and homemade clarified butter (ghee), when these were still a fairly regular part of the diet. I don’t know if now that I completely avoid all dairy I might have acute symptoms even with these. But anything more like ice cream, yogurt, and of course straight up milk cause severe symptoms.
Due to severe (I might die!) symptoms, I am not keen on testing tolerance or sensitivity level in any more detail.