Sweet-like syndrome and multiple COVID arm syndrome following COVID-19 vaccines: 'specific' patterns in a series of 192 patients.

The two clinico-pathological patterns are 'Sweet-like syndrome' and 'Multiple COVID-Arm'. 'Sweet-like syndrome' presents clinically as erythematous and oedematous papules or plaques, sometimes developing vesiculation or bullae. Histology shows classical Sweet syndrome with a diffuse dermal neutrophilic infiltrate, or an infiltrate of histiocyte-like immature myeloid cells consistent with a histiocytoid Sweet syndrome. 'Multiple COVID-arm' is characterized by multiple large inflammatory plaques with histological analyses showing a perivascular and interstitial inflammatory infiltrate with eosinophils.