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\begin{document}

\title{Rust-colored patches of the lower extremity in a COVID-19 patient}



\author[1]{Jacem Rouatbi}%
\author[1]{Mouna Korbi}%
\author[1]{Nouha Ben Abdeljelil}%
\author[1]{Hichem Belhadjali}%
\author[1]{Jameleddine Zili}%
\affil[1]{Fattouma Bourguiba University Hospital of Monastir}%


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  \date{March 13, 2025}


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\textbf{Title page}

\textbf{Title:} Rust-colored patches of the lower extremity in a
COVID-19 patient

\textbf{Authrors:} Jacem Rouatbi\textsuperscript{1}, Mouna
Korbi\textsuperscript{1*}, Nouha Ben Abdeljalil\textsuperscript{2},
Hichem Belhadjali\textsuperscript{1*}, Jameleddine
Zili\textsuperscript{1*}

\textbf{Affiliations:}

\textsuperscript{1}Dermatology Department, Fattouma Bourguiba University
Hospital, Monastir, Tunisia

\textsuperscript{2}Anatomopathology Department, Fattouma Bourguiba
University Hospital, Monastir, Tunisia

*Research Laboratory LR20SP03A

\textbf{Corresponding author} :

Dr Jacem Rouatbi;

Dermatology Department, Fattouma Bourguiba University Hospital,
Monastir, Tunisia

Email address\textbf{:}\emph{rouatbi.jacem@gmail.com}

ORCID ID: 0000-0003-3795-0846

Telephone number\textbf{:} 0021621255036

\textbf{CONFLICT OF INTEREST STATEMENT}

The authors have no conflicts of interest to declare.

\textbf{FUNDING SOURCES}

None

\textbf{ACKNOWLEDGEMENTS}

None

\textbf{CONSENT}

Written informed consent was obtained from the patient to publish this
report in accordance with the journal's patient consent policy

\textbf{DATA AVAILABILITY STATEMENT}

Data sharing is not applicable to this article as no new data were
created or analyzed in this study.

\textbf{AUTHOR CONTRIBUTION}

\textbf{Jacem Rouatbi:} ~Conceptualization; writing -- original
draft.~\textbf{Mouna Korbi:} ~Supervision; writing -- review and
editing.~\textbf{Nouha Ben Abdeljalil:} ~Investigation;
resources.~\textbf{Hichem Belhadjali:} ~Supervision;
investigation.~\textbf{Jameleddine Zili:} ~Supervision; validation;
Interpretation of data and revision of the manuscript.

\textbf{CASE PRESENTATION}

A previously healthy 67-year-old man presented to the Emergency
Department with fever evolving for 5 days and dry cough. Nasopharyngeal
swab polymerase chain reaction (PCR) confirmed Coronavirus disease 2019
(COVID-19) infection. The patient was diagnosed as a mild form of
COVID-19. He needed only symptomatic treatment and clinical monitoring.
Five days later, during his hospitalization in Infectious Disease
Department, we noted multiple asymptomatic golden brown-colored
infiltrated patches on the inner side of his left leg (Figure 1a). The
rest of physical examination did not show any abnormalities. He has
used, recently, only paracetamol. He denied any exposure to a new
product or trauma on both legs. Dermoscopic examination showed brownish
to coppery-red diffuse coloration of the background, round to oval red
dots and globules (Figure 1b). Histological examination of skin biopsy
revealed superficial dermal band-like infiltrate of lymphocytes and
histiocytes, red blood cells extravasation (Figure 2a). For further
confirmation, Perls' stain was performed and showed hemosiderin deposits
in the dermis (Figure 2b). The evolution was marked by spontaneous
disappearance of skin lesions 2 weeks after clinical recovery from
COVID-19.

\textbf{WHAT IS YOUR DIAGNOSIS?}

COVID-19-Triggered Lichen Aureus (purpuricus)

\textbf{COMMENT}

Skin vascular symptoms have been reported in patients with COVID-19
disease\textsuperscript{1}. The occurrence of livedo, necrotic or
non-necrotic purpuras is explained by the infection-related
coagulopathy\textsuperscript{1}. Our patient presented Lichen Aureus
(LA) in association with a mild form of COVID-19 disease. LA is a rare,
localized variant of pigmented purpuric dermatoses (PPDs) characterized
by the sudden onset of unilateral, well circumscribed, rust-colored
patches, usually on the lower legs, with particular dermoscopic
features, as was seen in our case\textsuperscript{2,3}. PPDs are also
known as capillaritis. Their precise cause remains unclear. Several
cofactors including venous hypertension, capillary fragility, infections
and drugs intake were suggested\textsuperscript{2}. One case of PPD was
described as Schamberg purpura in a 13-year-old child with mild COVID-19
infection\textsuperscript{4}. We think, in our case, LA may be
considered as a vascular skin manifestation associated with COVID-19.
However, the severe acute respiratory syndrome coronavirus-2 may lead to
excessive activation of inflammatory mediators creating a ``cytokine
storm'' which may cause damage to the endothelium in addition to changes
in the cellular component of immunity with activation of the complement
system\textsuperscript{1,4}. Thus, alteration of endothelial cells
function, causing red blood cells to leak through the vessel walls, may
be responsible in this case of triggering a cell-mediated
hypersensitivity reaction\textsuperscript{4,5}. Therefore, in our case,
cell-mediated immune response seems to have probably a role in the onset
of LA few days after first COVID-19 systemic symptoms.

In conclusion, our observation and the case about Schamberg disease
previously described suggest PPD as non-specific findings of SARS-CoV-2
infection\textsuperscript{4}. Although the relationship is not fully
elucidated, the knowledge of such cutaneous manifestations is worthwhile
to mention in order to help improve disease recognition and care.

\textbf{References}

\begin{enumerate}
\tightlist
\item
  Bouaziz JD, Duong TA, Jachiet M, et al. Vascular skin symptoms in
  COVID-19: a French observational study.~\emph{J Eur Acad Dermatol
  Venereol} . 2020; 34(9):e451-e452.
\item
  Kim DH, Seo SH, Ahn HH, Kye YC, Choi JE. Characteristics and Clinical
  Manifestations of Pigmented Purpuric Dermatosis.~\emph{Ann Dermatol} .
  2015; 27(4):404-410.
\item
  Zaballos P, Puig S, Malvehy J. Dermoscopy of pigmented purpuric
  dermatoses (lichen aureus): a useful tool for clinical
  diagnosis.~\emph{Arch Dermatol} . 2004; 140(10):1290-1291.
\item
  Wollina U. Schamberg-like purpuric eruptions and tonsillitis in mild
  COVID-19.~\emph{Dermatol Ther} . 2020; 33(4):e13766
\item
  Criado PR, Abdalla BMZ, de Assis IC, van Blarcum de Graaff Mello C,
  Caputo GC, Vieira IC. Are the cutaneous manifestations during or due
  to SARS-CoV-2 infection/COVID-19 frequent or not? Revision of possible
  pathophysiologic mechanisms.~\emph{Inflamm Res} . 2020; 69(8):745-756.
\end{enumerate}

\textbf{Figure Legends}

Figure 1: (a) Multiple asymptomatic golden brown-colored infiltrated
patches on the inner side of the left leg; (b) Brownish to coppery-red
diffuse coloration of the background, round to oval red dots and
globules (Dermlite DL4\selectlanguage{ngerman}®X40).

Figure 2: (a) Lichenoid lymphocytic inflammation at the dermis around
the small vessels with with minimal keratinocytic necrosis (Hematoxylin
Eosin X 100); (b) Perls stain highlights hemosiderin deposits in the
superficial~dermis.\selectlanguage{english}
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