Sweet’s syndrome and erythema nodosum following simultaneous COVID-19 and influenza vaccination: a report of two cases

Ana C. Freitas, Department of Haematology, Instituto Português de Oncologia de Lisboa Francisco Gentil, Lisboa, Portugal Gabriela C. M. Alé, Institute of Dermatology Professor Rubem David Azulay – Santa Casa da Misericordia do Rio de Janeiro, Rio de Janeiro, Brazil Daniela K. Stolnicki, Institute of Dermatology Professor Rubem David Azulay – Santa Casa da Misericordia do Rio de Janeiro, Rio de Janeiro, Brazil Marcus Trovó, Institute of Dermatology Professor Rubem David Azulay – Santa Casa da Misericordia do Rio de Janeiro, Rio de Janeiro, Brazil Danielle C. Quintella, Department of Pathology, Institute of Dermatology Professor Rubem David Azulay – Santa Casa da Misericordia do Rio de Janeiro, Rio de Janeiro, Brazil Fernando M. Belles, Department of Pathology, Institute of Dermatology Professor Rubem David Azulay – Santa Casa da Misericordia do Rio de Janeiro, Rio de Janeiro, Brazil Tullia Cuzzi, Department of Pathology, Institute of Dermatology Professor Rubem David Azulay – Santa Casa da Misericordia do Rio de Janeiro, Rio de Janeiro, Brazil

Sweet syndrome (SS) and erythema nodosum (EN) are dermatoses triggered by factors such as vaccination. We report two cases of EN and SS simultaneously, following vaccination against COVID-19 and influenza, in female patients, in their fourth decade of life, presenting with painful erythematous papules on the upper limbs, painful nodules on the lower limbs, and fever, with no relevant laboratory alterations. Histopathological examination of the lesion on the arm confirmed SS and, on the leg, EN. Treatment with systemic corticotherapy induced complete resolution of the conditions. Postvaccination cutaneous reactions are rare and can occur in association with the vaccine or the adjuvant. We cannot infer whether the cases were due to the influenza vaccination, the COVID-19 vaccination, or a combination of both vaccines. However, as these are the cases of two concomitant dermatoses after simultaneous vaccination, something not reported in the literature, the communication of these cases is relevant in the current global health situation.

Keywords: Sweet syndrome. Erythema nodosum. Vaccine. Case report.