Toxic erythema as the first sign of COVID-19 infection.

During the COVID‐19 pandemic, dermatologists have sought to identify and categorize skin manifestations associated with COVID‐19, in the hope that it will aid early recognition and treatment of the condition, and provide insight into the pathophysiology of the disease. Urticarial, purpuric, maculopapular and acral rashes have been described in the literature to date., We report a patient presenting with toxic erythema as the first sign of COVID‐19 infection.

A 64‐year‐old woman presented with a 1‐week history of a sore, itchy red skin eruption that started on her trunk and rapidly spread to her limbs and face. A few days before the rash appeared, she had taken paracetamol for a mild headache, but reported no other prodromal symptoms. Despite treatment with loratadine, prednisolone and flucloxacillin, the rash continued to progress. The patient subsequently presented to hospital and a dermatology review was sought. Following admission, she developed a fever, accompanied by a dry cough and was found to be hypoxic requiring oxygen.

Physical examination revealed sharply demarcated areas of erythema, extending from the patient’s trunk to her upper thighs and the inner aspect of her arms. The lesions were not tender and were blanching, but warm to touch, and there was associated facial oedema and erythema (Fig. 1). The differential diagnosis included a viral exanthem or a drug eruption.

Figure 1

Well‐demarcated areas of erythema, extending from the patient’s (a) trunk to her (b) upper thighs, and (c) the inner aspect of her arms.

Histological examination of a skin biopsy showed widespread epidermal lymphocytic exocytosis associated with spongiosis. There was evidence of interface dermatitis and marked oedema in the papillary dermis with a perivascular infiltrate of lymphocytes in the upper dermis consistent with a viral exanthem. Direct immunofluorescence was negative (Fig. 2).

Figure 2

Widespread epidermal lymphocyte exocytosis associated with prominent spongiosis and red blood cell extravasation consistent with a viral exanthem. There was evidence of prominent interface dermatitis and marked oedema in the papillary dermis and prominent perivascular infiltrate of lymphocytes in the upper dermis. Haematoxylin and eosin, original magnification × 200.

Blood tests showed raised C‐reactive protein level and white blood cell count but eosinophil count was normal. No obvious focus of bacterial infection was found. Subsequent investigations, including COVID‐19 PCR and chest radiography, confirmed a diagnosis of COVID‐19 pneumonitis. The patient was commenced on oral dexamethasone, which led to rapid improvement in the rash and the systemic symptoms. She was eventually discharged having recovered from COVID‐19 infection.

Morbiliform eruptions are commonly seen as part of a spectrum of skin eruptions associated with acute viral infections. The exact mechanism for erythema in the context of COVID‐19 infection is still unknown, but a recent systematic review revealed that the majority of skin manifestations occurred after the onset of systemic symptoms., Recent reports from Spain described patients with COVID‐19 presenting with pseudochilblain‐like, vesicular, urticarial, maculopapular or livedoid rashes. Importantly, the authors questioned whether skin manifestations should feature as a clinical sign of COVID‐19 in view of the high number of patients presenting with skin disease.

This case adds further evidence to this proposal, and to our knowledge, is the first report of COVID‐19 infection presenting as widespread macular toxic erythema in the absence of systemic symptoms. We consider it important to recognize COVID‐19 infection as a differential for a toxic exanthemous skin eruption during this pandemic, especially in the context of novel treatments that may improve mortality.