Diagnosing 'COVID toes' and other challenges in the derm-rheum overlap
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So-called “COVID toes” and other cutaneous manifestations of the virus are not the only dermatologic challenges that a rheumatologist may face, according to a presenter at the 2021 Congress of Clinical Rheumatology-East.
“I wanted to continue through in a very clinically oriented and case-based fashion some of the overlap in our two specialties,” Alisa N. Femia, MD, a dermatologist at NYU Langone Health, told attendees. “The focus is on cases that rheumatologists may not see frequently.”
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She first described a patient with lupus who had bullous, blistering dermatoses in the oral mucosa and other parts of her skin. “When I see bullous lupus on the skin I think severe acute cutaneous lupus flare,” Femia said.
The malar rash can present like disseminated acute cutaneous lupus with robust lymphocytic and neutrophilic involvement. However, the patient had other areas that were not so inflammatory, and the bulla were “denuded,” according to Femia.
“The diagnosis was epidermis bullosa acquisita, or EBA,” she said. “I wanted to bring it to your attention because of its overlap with rheumatologic conditions. It can be seen in systemic lupus and inflammatory bowel disease, with a straight blister formation in the dermis/epidermal junction.”
Regarding treatment of EBA in the setting of lupus, Femia noted that this condition does not generally respond well to immunosuppressive therapy. “It may be easier to treat in underlying [systemic lupus erythematosus],” she said.
Moving on to acral purpura, Femia stressed that unexplained purpura can signify systemic disease. She reviewed a patient with purpuric dermal hemorrhage whose bloodwork showed elevated creatinine and NPL antibodies. “A relatively subtle purpura can clue us into systemic disease,” she said.
With that in mind, she sent samples for biopsy. “I need to have proof that it is not something bad.”
As far as a clinical workup for a patient with suspected acral purpura, Femia noted that there is no algorithm currently in place. “It is based on symptoms, underlying disease and medications,” she said. A key point is to do enough tests to make sure there is no end organ involvement.
Ultimately, the case patient was diagnosed with ANCA-associated vasculitis, which confirmed Femia’s point that purpura can signify something systemic.
Another clinical conundrum that may appear in a rheumatology clinic is pernio or chilblains versus vasculitis. “Pernio occurs in cooler, damper weather,” Femia said. “Also, pernio will not necrose. These patients are not in danger of losing their digits.”
Femia closed her talk with a review of dermatologic manifestations associated with COVID-19. She admits that she was “quite skeptical” of reports of so-called “COVID toes” emerging out of early hotspots like Israel and Italy. “I was not seeing much of this.”
That changed in May 2020, when her clinic began seeing increasing incidence of new onset pernio that coincided with COVID-19 infection or exposure to the virus. “It was pretty consistent,” she said. “About 2 to 4 weeks following a peak of COVID-19, there would be a peak of pernio or chilblains. It was certainly an epiphenomenon.”
The jury is out as to whether these events are actually part of the progression of the COVID-19 virus, according to Femia. One possibility is that COVID-19 is triggering autoimmune processes linked to disruptions in the type I interferon signaling pathway. Another is that pernio has always been virally triggered, and it was not until COVID-19 that that aspect of the condition came into clear focus.
“But it may be just associated with lockdown and changes in behavior associated with lockdown,” Femia said.
One other possible cutaneous manifestation of COVID-19 is retiform purpura, according to Femia. “A possible etiology is the ulcerations in COVID,” she said. “A lot of patients were developing retiform purpura without any other explanation.”
Femia suggested that clinicians look for this manifestation in patients who required mechanical ventilation. But she stressed that nothing is certain.
“This is an evolving virus,” she said. “There are things we don’t know about this virus.”
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Femia AN. Dermatology for the Rheumatologist, Part II. Presented at: Congress of Clinical Rheumatology-East annual symposium; August 12-15, 2021 (hybrid meeting).
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