The dermatological manifestations of CoVID-19 infection (CI) are variable, including livedo/necrosis, pseudochillblains, vesicular (monomorphic vesicles unlike varicella), urticarial and maculopapular subtypes. 1 We report the cutaneous manifestations of two Han-Chinese patients in Singapore with CI and highlight their instructive features.
Case 1 is a 43-year-old man with CI who developed truncal and limb rashes 12 days after onset of respiratory symptoms.
Drug history was non-contributory. Examination revealed erythematous, blanchable, non-follicular papules on his trunk (Fig. 1a) , proximal thighs and intertriginous areas including bilateral axillae (Fig. 1b) and groin. Additionally, non-follicular pinpoint pustules were admixed within the intertriginous areas (Fig. 1c) . There was no acral involvement.
Skin biopsy of a papule from Case 1 demonstrated spongiotic and interface dermatitis, with superficial perivascular infiltrate of predominantly lymphocytes (Fig. 2a) , and focal erythrocyte extravasation without vasculitis (Fig. 2b ). An area showed tight perivascular cuff consisting of lymphocytes and infrequent plasma cells, in association with intraluminal neutrophilia (Fig. 2c ). There were no viral cytopathic or herpetic changes seen.
He was diagnosed with a papulopustular exanthem secondary to CI, which resolved with topical corticosteroids within 7 days.
Case 2 is a 75-year-old woman with severe CoVID pneumonia developed purpuric plaques on her abdomen and back ( Fig. 1d ) 15 days after her respiratory symptoms. The patient was not coagulopathic, and there was no peripheral eosinophilia. She had received four days of lopinavir-ritonavir (Kaletra) prior to her rashes, which was discontinued thereafter. Nikolsky sign was negative, and there was no mucositis. A skin biopsy was not performed. She was diagnosed with a purpuric exanthem from CI. There was complete clearance with topical corticosteroids when she was discharged 10 days later. Reports of CI-related cutaneous manifestations have largely emerged from Europe and North America. Similar reports from Asia have been disproportionately low despite the infection being first discovered on this continent. Indeed, the incidence of rashes was 0.2% amongst a cohort of 1099 patients in China. 2 Correspondingly, there is a paucity of clinicopathologic and photographic descriptions of such eruptions within this demographic.
We describe two Han-Chinese patients in Singapore with CI who developed distinctive rashes. Case 1 highlights the novel non-acral papulopustular morphology that has not been described hitherto, further broadening the phenotypic spectrum of CI-related exanthems. Whilst petechial eruptions have been described, 3, 4 florid purpuric exanthem with ecchymotic areas is rare. We opine that the rash was unlikely Kaletra-induced in Case 2 as a four-day latency without prior exposures is relatively short for type 4 hypersensitivity reaction. Moreover, resolution was expedient and precisely mirrored the patient's recovery from CI and inability to detect CI from her respiratory secretions.
Notably, we have not encountered CI-related dermatoses which are conventionally precipitated by cooler temperatures (e.g. pseudochillblains and livedo), which have been reported in European centres. 1 We hypothesize that geographically determined climatic variations contribute to variability in cutaneous manifestations. Moreover, genetic differences between Caucasians and Asians may ultimately influence the incidence and repertoire of cutaneous responses to CI.
From a dermatopathological viewpoint, the coat-sleeve appearance seen in case one, typified by a tight superficial perivascular lymphoplasmacytic infiltrate, is a new finding in the histology of CI dermatoses. Coat-sleeving, archetypal in erythema annulare centrifugum and secondary luetic disease, may be a unique histopathological finding in CI (in addition to microthrombi 5 and superficial dermal vessel ectasia 6 ), which can point the clinician to the diagnosis of CI. This is especially when it is encountered with other non-specific histological findings compatible with a viral exanthem.
Our observations underscore the different morphologies of CI-related cutaneous eruptions in South East Asia and showcase, for the first time, a non-acral papulopustular eruption with its associated coat-sleeve infiltrate histologically.
Dr(s) Wen Yang Benjamin Ho, Chee Hian Tan, Llewelyn Yi Chang Tan, Bundele Manish Mahadeorao, Dingyuan Wang and Hua-Liang Joel Lim contributed equally to this manuscript and had full access to the above data. All of the authors above take full responsibility for the integrity of the data and the accuracy of the data analysis. 