Bruises on my arm again (thrombotic thrombocytopenic purpura)

I guess I overdid it with killing off bacteria, because I've now got a half dozen bruises on my arm.

This is thrombotic thrombocytopenic purpura, an autoimmune disorder that causes microclots and depletion of platelets. This occurs when an infection gets into the vascular endothelium, and the B cells produce antibodies in response. The endothelium produces a clot-dissolving protein, ADAMTS13, and this gets presented to the B cells along with bits of the pathogen, resulting in autoantibodies against the clot-dissolving protein.

I'm surprised at how localized this is, as it's just in one arm. One would think that low platelets would result in bruises all over, and sometimes this is the case, but this time it's just one arm. I guess that a low platelet count alone is not sufficient to cause such bruising, but that there also must be some trauma or inflammation in a specific area. I'm also not getting a lot of kidney problems or polyuria this time.

I didn't go get blood tests this time to confirm the low platelets or autoantibodies. I didn't feel well, so I just stayed home. I already knew what the problem was.

I know from past experience that taking low doses of bacteriostatic antibiotics will resolve it. This is presumably because this keeps the bacteria immobile without causing a lot of die-off that will trigger an inflammatory response and antibody production. The annoying thing is that it can take a while for the B cells to become inactivated and stop producing the unwanted antibodies.

The first time this happened, I was taking valacyclovir. Lately I've been taking famciclovir and lamivudine instead, but it's the same mechanism - borrelia gets into the endothelium and dies there, because borrelia DNA polymerase is vulnerable to the nucleotide analogues. Covid can also damage the endothelium, so maybe I got covid and didn't realize it. I took some atovaquone just in case, as I've found that atovaquone is effective for covid.