key: cord-0715705-8e00yauk
authors: Lehmann, M.; Schorno, P.; Hunger, R.E.; Heidemeyer, K.; Feldmeyer, L.; Yawalkar, N.
title: New onset of mainly guttate psoriasis after COVID‐19 vaccination: a case report
date: 2021-08-04
journal: J Eur Acad Dermatol Venereol
DOI: 10.1111/jdv.17561
sha: dd654cadfcf1df6c486cc050edc37570a74a289a
doc_id: 715705
cord_uid: 8e00yauk

Psoriasis is a chronic, immune-mediated inflammatory disease with heterogeneous clinical manifestations. Various trigger factors like infections and drugs are known to elicit or aggravate psoriasis. Previously, a possible association of vaccination and the new onset (particularly guttate lesions) or exacerbation of psoriasis has been reported.

back and scalp. After some improvement with topical clobetasol propionate ointment once daily, the second dose of Comirnatyâ was given, which again led to a flare-up particularly on her arms and legs. The patient is currently on treatment with topical calcipotriol/ betamethasone ointment and UVB phototherapy.

In order to characterize the skin lesions, histological [Haematoxylin & Eosin (H&E) staining] and immunohistochemical examinations of a lesional punch biopsy specimen were performed. Histopathological examination showed an acanthotic epidermis with focal loss of the granular cell layer and a compact hyperparakeratosis alternating with orthokeratosis, as well as superficial perivascular lymphohistiocytic infiltrates with a few scattered neutrophils, consistent with guttate psoriasis (Fig. 1c) . Immunohistochemical analysis using the avidin-biotin complexalkaline phosphatase (ABC-AP) method was performed with following primary antibodies: CD1a (clone MTB1; Leica Biosystems, Nussloch, Germany), CD4 (clone 4B12; DakoCytomation, Glostrup, Denmark), CD8 (clone 4B11; Leica Biosystems), CD11c (clone 5D11; Novocastra, Muttenz, Switzerland), CD32 (clone EPR6657; Abcam, Cambridge, MA, USA), CD68 (clone PG-M1, DakoCytomation), CD163 (clone EDHU-1; Serotec MCA, Oxford, UK), CD303/BDCA2 (clone 124B.13, Dendritics, Lyon, France), Mx1 (polyclonal rabbit antibody, GenTex, CA, USA). Irrelevant immunoglobulin G subclass-matched antibodies were used for negative controls. As shown in Fig. 2 , a marked infiltration of T cells (CD4 + > CD8 + T cells) and different Letter to the Editor dendritic cell (DC) subsets like Langerhans cells (CD1a + ), myeloid DCs (CD11c + ) and to a lesser extent plasmacytoid DCs (BDCA-2 + ) were found in the skin sections. Furthermore, different macrophage subsets including M1-like (CD68, CD32) and M2-like (CD163) macrophages were also observed. The immune response in psoriasis involves an aberrant interplay of innate and adaptive immunity, and all of these different subsets of dendritic cells, macrophages, and T cells have been associated with the immunopathogenesis of the disease. Myeloid DCs and macrophage are the main source of TNFa and IL-23, which are pivotal cytokines driving the activation and expansion of pathogenic type-17 T cells and subsequent stimulation of keratinocytes in psoriasis. Interestingly, strong focal expression of MX1 [surrogate marker of type I interferon (IFN)] was detected in the keratinocytes and mononuclear infiltrate. Type I IFNs are upregulated in psoriasis and their production by plasmacytoid DCs (pDC) has been reported to initiate psoriasis. 3 Recently, MX1 expression has also been shown to be enhanced in COVID-19 patients and in COVID-19-associated perniosis. 4, 5 Single-stranded mRNA vaccines can activate immune responses via binding to Toll-like receptors (e.g. TLR7 on pDCs) resulting in production of type I IFNs, multiple proinflammatory cytokines and both CD4 + and CD8 + T cells. 6 We speculate that such mechanisms may lead to elicitation of guttate psoriasis in susceptible persons. However, whether COVID-19 vaccines directly stimulate local MX1 (Type I IFNs) in the skin remains to be elucidated in future studies. Taken together, the close temporal relationship between the COVID-19 vaccination and the onset of psoriasis (i.e. the repeated flare-up after the second dose) and the lack of any other trigger factors (no infections or new medication) strongly suggests a causal association in this case. With the increasing number of people receiving a COVID-19 vaccination, dermatologists should maintain an index of suspicion for this putative side effect.

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The patient in this manuscript have given written informed consent to publication of her case details.

The authors have no conflict of interest to declare.

This article has no funding source.