Right now, my workup includes nasal swab PCR for COVID, and IgG and IgM serology if available. We have IgG easily available to us. IgM needs approval; at UCSF, it is primarily done in neonates as of now. I also do a workup for autoimmunity and cold-associated disease, which includes an ANA, rheumatoid factor, cryoglobulin, and cold agglutinins.
Because of reported concerns about hypercoagulability in COVID patients, particularly in those who are doing poorly in the hospital, we look for elevations in D-dimers and fibrinogen. We check antiphospholipid antibodies, anticardiolipin antibodies, ESR, and CRP. That is probably too much of a workup for the healthy young person, but as of yet we are just unable to say that those things are universally normal.
There has also been concern that complement may be involved in patients who do poorly and tend to clot a lot. So we are also checking C3, C4, and CH50.
To date, in my patients who have had this workup, I have found one with a positive ANA that was significant (1:320) who also had low complements.
There have been a couple of patients at my institution, not my own patients, who are otherwise fine but have some slight elevation in D-dimers.
Is COVID Toes More Than One Condition?
Some of the initial reports of finger/toe cyanosis out of China were very alarming, with many patients developing skin necrosis or even gangrene. These were critically ill adults with pneumonia and blood markers of disseminated intravascular coagulation, and 5 out of 7 died. In contrast, the cases of pseudo-pernio reported in Europe, and now the US, seem to be much milder, usually occurring late in the illness or in asymptomatic young people. Do you think these are two different conditions?
I believe you have hit the nail on the head. I think it is really important that we don’t confuse those two things. In the inpatient setting, we are clearly seeing patients with a prothrombotic state with associated retiform purpura. For non-dermatologists, that usually means star-like, stellate-like, or even lacy purpuric changes with potential for necrosis of the skin. In hospitalized patients, the fingers and toes are usually affected but, interestingly, also the buttocks. When these lesions are biopsied, as has been done by our colleague at Cornell, Joanna Harp, we tend to find thrombosis.