Hello. Thank you for asking at HCM. I went through your history and would like to make suggestions for your sister as follows: 1. First of all, I assume that she really has anahylaxis. Unfortunately there are no tests available that can reliably diagnose anaphylaxis. So it s only listening to her symptoms the diagnosis is usually made. But there are other conditions also that might mimic anaphylaxis. However, sudden onset itchy rashes and breathing difficulty together can be symptoms of diagnosis. 2. If the cause is not known, occurrence of anaphylaxis cannot be predicted. So the best strategy is to keep injectable adrenaline (in some countries autoinjectors are also available) with her. Whenever should she develops symptoms, she should inject the adrenaline herself; it could be life saving. Again, please make sure with her doctor that she really has anaphylaxis so that he can prescribe adrenaline to her. 3. Regarding cause, it can occur due to food-borne allergens, air-borne allergens, some drugs, insects stings/bites and sometimes without known cause. Common foods are - milk, egg, peanut, soy, tree nuts (almond, cashew, pistachio, walnut, etc), fish, wheat, shell fish, etc. As you correlate with protein powder, please try to correlate the contents with above. If the food is identifies, avoidance is the best strategy. Common drugs are NSAID pain killers (other than paracetamol) - like ibuprofen, diclofenac, aspirin, etc, and antibiotics like penicillins. Sometimes association of occurrence of anaphylaxis with menstruation or exercise may also be present. 3. Please try to correlate her occurrences with above mentioned anaphylaxis triggers. If she can identify the trigger, avoidance will be the best. Hope above suggestions and information will help her. Should you/she have any other query, please feel free to ask at HCM. Wish your sister the best of the health. Thank you & Regards.