Annular lichen planus associated with coronavirus SARS‐CoV‐2 disease (COVID‐19)

Abstract

Dear Editor, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been associated with cutaneous manifestations. This letter reports a case of annular lichen planus (LP) associated with a confirmed coronavirus disease 2019 (COVID-19) case. A 52-year-old female presented to our Emergency Department (ED) in July 2020, during the COVID-19 pandemic. She complained of a pruritic solitary skin lesion on the right shin that had appeared in May. She had not started any new medications the year before and was not taking any drugs chronically. She reported the lesion had started 5 days after the onset of an episode of fever, cough, and malaise which was diagnosed as a mild case of COVID-19 due to a positive real-time reverse transcription polymerase chain reaction (rRT-PCR) for SARS-CoV-2 from a nasopharyngeal swab. Posteroanterior and lateral chest radiographs had been performed, showing no pulmonary infiltrates, and ruling out pneumonia. She had been treated at home with acetaminophen 650 mg t.i.d for 7 days, with resolution of fever and coughing after 4 days. She had tested negative in a second rRT-PCR extracted 7 days after the onset of the fever. Despite that, the lesion had continued to grow. Dermatological examination at the ED showed a black annular plaque with a whitish rim on the right shin that measured 2 cm in diameter (Fig. 1a). Polarized dermoscopy displayed a network of whitish lines with an orthogonal disposition, compatible with Wickham striae (Fig. 1b). The rest of the skin was unaffected. Both buccal mucosae showed reticular white lines in a lace-like pattern (Fig. 1c). She reported no oral symptoms. She did not have amalgam fillings nor did she wear any dental prothesis. CBC was normal. Serologies for hepatitis C virus (HCV), HBV, and HIV were negative. Two 4-mm punch biopsies were taken from the left border of the plaque (H&E examination, rRT-PCR). H&E showed orthokeratosis, an acanthotic “sawtooth” epidermis with hypergranulosis and basal necrotic keratinocytes. There was a dense band-like lymphocytic infiltrate at the dermal-epidermal junction, with scattered dermal melanophages. Skin rRT-PCR was negative for SARS-CoV-2. Treatment with clobetasol propionate 0.05% cream b.i.d for 14 days was instituted. She refused treatment for the oral lesions. After 10 days of treatment, the pruritus ceased and the plaque became a residual brown patch (Fig. 2a,b). No recurrence has been noted. Some skin manifestations of SARS-CoV-2 have already been described.1 At the time of manuscript redaction, there are no reports of annular LP in a SARS-CoV-2-positive patient. LP is a T-cell mediated autoimmune disorder that arises after the exposure to many agents (viruses, drugs, contact allergens).2 The hypothesized pathogenesis is the cross-reaction of T cells primed by those agents with epidermis-restricted antigens. Viruses, particularly HCV, have been associated with this disease. Several studies have found a higher prevalence of HCV antibodies among patients with LP compared with controls.3 One study detected HCV RNA in 93% of oral LP lesions, while another found that five out of seven patients with anti-HCV antibodies had demonstrable HCV RNA in lesional skin biopsies.4, 5 The association between COVID-19 and LP might have been coincidental. Nevertheless, viral infections have been proposed to be a triggering event for LP pathogenesis. Even if we explored that possibility, we believe that the negative skin rRT-PCR result is not necessarily incompatible with SARS-CoV-2 having been the trigger. The hypothetical SARS-CoV-2 primed T-cells that could have cross-reacted with the epidermis-restricted antigens might have originated during the mild COVID-19 episode and could have persisted afterwards. It might have been possible to detect SARS-CoV-2 RNA in the skin at that first moment. More studies are needed in order to substantiate the association between SARS-CoV-2 and LP. The patients in this manuscript have given written informed consent to the publication of their case details.

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