Pemphigus is a group of blistering disorders characterized by the formation of intraepithelial blisters in skin and mucous membranes induced by the binding of circulating autoantibodies to intercellular adhesion molecules. The pathogenesis is complex and not fully understood; however, genetic predisposition and various triggers are widely accepted as key factors in pemphigus development. A few cases of new‐onset pemphigus following coronavirus disease 2019 (COVID‐19) vaccination have already been published. The present paper reports a total of two cases of pemphigus foliaceous and three cases of pemphigus vulgaris that occurred following vaccinations against COVID‐19, with anamnestic, clinical, and diagnostic data collection suggesting assumptions over a possible causal correlation.

Background Steatocystoma multiplex (SM) is an uncommon skin disease manifesting as multiple sebum‐containing cysts arising in pilosebaceous unit‐rich body areas. Hidradenitis suppurativa (HS) is a debilitating chronic inflammatory disease affecting the apocrine gland‐bearing skin and presenting with both pseudocystic and inflammatory nodules, abscesses and fistulas. Considering that genetics has been reported to play a role in both entities, the albeit rare association between them suggests a shared genetic background. Although histology remains the gold standard for the diagnosis of SM, ultrasonography can be an useful diagnostic tool. This method is largely used in combination with Color Doppler for assessing disease severity in HS. Materials and Methods We report three cases of coexisting SM and HS and describe the ultrasonography and Color Doppler features of the two entities. Results SM lesions appeared on ultrasonography as hypoechoic nodules with well‐defined hyperechoic borders and posterior acoustic enhancement, in the absence of Color Doppler signal. HS lesions had the ultrasonographic features of the fistulas, abscesses and pseudocystic nodules, some of which including hair fragments, with an intense Color Doppler signal within or around inflamed lesions. Conclusion The combination of ultrasonography and Color Doppler proved to be a reliable instrument for differentiating between SM and HS lesions, particularly distinguishing HS pseudocystic nodules from true cysts of SM.

Introduction: pemphigus vulgaris is a rare autoimmune blistering disease that involves the skin and mucous membranes and rarely occurs in pediatric age. Methods: we present a case of childhood pemphigus in a 9-year-old patient from Burkina Faso, which initially manifested with erosive lesions symmetrically distributed in the oral cavity. After a few months, we also observed hyperchromic lesions of the back. Histopathological examination of skin samples showed intraepidermal acantholysis, while direct immunofluorescence showed deposits of complement (C3) and immunoglobulins G (IgG) in the epidermidis; an ELISA test highlighted the presence of circulating autoantibodies against desmoglein 3. Results: the follow-up of this patient was made difficult by the advent of the COVID-19 outbreak. However, after about one year of combined therapy with systemic steroids and azathioprine the patient reached clinical remission.