Guttate Psoriasis Following COVID-19 Infection

Psoriasis is an inflammatory skin condition affecting 1% to 5% of the world population. ¹ Guttate psoriasis is a subgroup of psoriasis that most commonly presents as raindroplike, erythematous, silvery, scaly papules. There have been limited reports of guttate psoriasis caused by rhinovirus and COVID-19 infection, but a PubMed search of articles indexed for MEDLINE using the term COVID-19 guttate psoriasis yielded only 3 documented cases of a psoriatic flare secondary to SARS-CoV-2 infection. ^1-4 Herein, we detail a case in which a patient with mild SARS-CoV-2 infection who did not have a personal or family history of psoriasis experienced a moderate psoriatic flare 3 weeks after diagnosis of COVID-19.

Case Report

A 55-year-old woman was diagnosed with COVID-19 after SARS-CoV-2 RNA was detected from a nasopharyngeal swab. She reported moderate fatigue but no other symptoms. At the time of infection, she was not taking medications and reported neither a personal nor family history of psoriasis.

Three weeks after the COVID-19 diagnosis, she reported erythematous scaly papules only on the trunk and backs of the legs. Two months after the COVID-19 diagnosis, she was evaluated in our practice and diagnosed with guttate psoriasis. The patient refused biopsy. Physical examination revealed that the affected body surface area had increased to 5%; erythematous, silvery, scaly papules were found on the trunk, anterior and posterior legs, and lateral thighs (Figure). At the time of evaluation, she did not report joint pain or nail changes.

A and B, Guttate psoriasis that manifested as erythematous, silvery, scaly papules 3 weeks after COVID-19 infection.

The patient was treated with triamcinolone acetonide cream 0.1% twice daily for 2 to 4 weeks. The guttate psoriasis resolved.

Comment

A sudden psoriatic flare can be linked to dysregulation of the innate immune response. Guttate psoriasis and generalized plaque-type psoriasis are postulated to have similar pathogenetic mechanisms, but guttate psoriasis is the only type of psoriasis that originates from viral infection. Initially, viral RNA will stimulate the toll-like receptor 3 protein, leading to increased production of the pathogenic cytokine IL-36γ and pathogenic chemokine CXCL8 (also known as IL-8), both of which are biomarkers for psoriasis.¹ Specifically, IL-36γ and CXCL8 are known to further stimulate the proinflammatory cascade during the innate immune response displayed in guttate psoriasis.^5,6

Our patient had a mild case of COVID-19, and she first reported the erythematous and scaly papules 3 weeks after infection. Dysregulation of proinflammatory cytokines must have started in the initial stages—within 7 days—of the viral infection. Guttate psoriasis arises within 3 weeks of infection with other viral and bacterial triggers, most commonly with streptococcal infections.¹

Rodríguez et al⁷ described a phenomenon in which both SARS-CoV-2 and Middle East respiratory syndrome, both caused by a coronavirus, can lead to a reduction of type I interferon, which in turn leads to failure of control of viral replication during initial stages of a viral infection. This triggers an increase in proinflammatory cytokines and chemokines, including IL‐36γ and CXCL8. This pathologic mechanism might apply to SARS-CoV-2, as demonstrated in our patient’s sudden psoriatic flare 3 weeks after the COVID-19 diagnosis. However, further investigation and quantification of the putatively involved cytokines is necessary for confirmation.