The allergic symptom can be caused by the radiowave manipulation, but it is not yet elucidated how it is triggered physiologically. As far as I can conclude, the electromagnetic wave cannot create the allergy to the specific object, such as allergy to pollen, wheat or whatever. On the other hand, it can create the similar feeling as you are exposed to the allergen.
It is a vague symptom felt in the whole body, which is a little different from an itching caused by the electromagnetically. The itching is often triggered locally, as the chemical substances are secreted at one spot irradiated by the radiowave, which is not just a result of the pure brain activity.
It is hard to conclude how it is exactly controlled, but it is more like the radiowave pattern is accumulated from the past executions, which is irradiated again to recreate the same symptoms. If that is the case, the wave just regenerates the same feeling in the past, not yielded from a research experiment. This can be applicable to the local pain, felt as stabled at one spot, which is torturing, but the ache is superficial not profound, i.e. not escalated into the disease.
On the other hand, the allergic symptom is felt all over the body. One explanation is that there is a way to enhance its symptom by the electromagnetic wave. Each emotion is exacerbated by the electromagnetic wave, hence the same frequency pattern can enhance the symptom more serious. It implies the allergic symptom can be escalated to the hypersensitivity, though it has not been yet proved.
Otherwise, there should be a specific frequency pattern for the allergic symptom, which can be recreated by the electromagnetic wave. You should feel exposed to an allergen and tremor slightly inside the body, though it is not escalated into the severe symptom. If you are exposed to the allergen at this time moment, you symptom might be exacerbated by this manipulation.
The point is that the allergic symptom is caused by the electromagnetic wave, but it has still not been elucidated yet how to occur. The chemical reaction is apparently triggered by the wave, though it is hard to contain the symptom, if not understanding its mechanism. This might be escalated to a serious symptom, hence it cannot be left as unimportant.