Technically mental trauma could have done so as well - which you probably heard dozens of times. Even if a doctor believed you I am not sure what they could do that wouldn't be extremely ill advised. Immunosuppressants would be tough to justify even if it was a certain cure instead of a highly tentative one.

I know it is a frustrating situation to be in. Like I know that oral general anesthesia would help me for bloodwork given a severe phobia (multiple panic attacks while maxed oral dose and too tranqed to walk normally bad) but even without asthma and weight the risk would be too off-kilter to do without qualifying as malpractice. Let alone insurance and expenses. Unfortunately the field seems to select for people who see it as a nonissue.