The pandemic outbreak of Coronavirus Disease 2019 (COVID-19) led to the development of mRNA vaccines. With the extensive vaccination campaign performed worldwide, many adverse reactions to these drugs have been reported in the literature. Although most of them are mild and self-limiting, they may sometimes cause psychological stress and require efforts to make a differential diagnosis with other conditions. This is the case of lymphadenopathies and lymphedema in patients with a history of cancer. Herein we present a case of lymphedema of the arm developed ten days after a VAXZEVRIA COVID-19 vaccine shot in a patient who had concomitant signs and symptoms compatible with a diagnosis of dermatomyositis. It was later classified as paraneoplastic as instrumental investigation revealed a breast carcinoma contralateral to the site of vaccine injection. With this report we ponder an adverse reaction to COVID-19 vaccination with the aim of bringing new data for clinicians who face similar clinical presentations, particularly controversial for radiologists and oncologists.

Multicentric reticulohistiocytosis (MRH) is the most frequently described form of reticulohistiocytosis (RH), and it is classified as a class IIb non-Langerhans cell histiocytosis. It has been designated as multicentric, being characterized by multisystemic involvement. In fact, although mainly involving the skin, along with the joints, it is a systemic inflammatory condition potentially involving every internal organ. As MRH-related skin findings can mimic rheumatoid nodules or Gottron papules, the histopathology of the cutaneous lesions is often necessary for the correct diagnosis. Approximately one-third of MRH patients have confirmed concomitant autoimmune disorders. A wide variety of autoimmune disorders associated with the disease have been reported in the literature, suggesting immune dysfunction as a factor in the pathophysiology of MRH. A case of MRH associated with autoimmune manifestation is reported in the context of a mini review of the literature, with a focus on clinical presentation, treatments, and treatment outcomes. Moreover, eight cases of MRH associated with autoimmune diseases are briefly discussed.

It is well known that viral infections play a relevant role in inducing or protecting from autoimmune diseases, thus representing a major environmental factor in the disruption of the immune system in genetically susceptible individuals. Since the beginning of the Covid-19 pandemic a great number of clinical and epidemiological studies have demonstrated that SARS-CoV-2 infection is no exception to the rule by interfering on many different levels in the normal functioning of our immune system. Even though a growing number of case series and case reports has been cited in the literature linking the infection to the new onset of autoimmune diseases, to date very little has been reported concerning a possible correlation between the virus and the clinical resolution of any kind of autoimmune pathology. Here we describe an interesting case of abrupt and unexpected resolution of Lichen planus pemphigoides mucocutaneous lesions in a fully vaccinated patient after a mildly symptomatic SARS-CoV-2 respiratory infection and we speculate on the possible underlying mechanisms correlating the two events.

The association between psoriasis and streptococcal infection has been widely explored in both children and adults. However, the exact impact of Streptococcus pharyngeal infection on the course of psoriasis is not fully comprehended. This study explored the impact of Streptococcus pharyngeal infection on psoriasis and investigated the effectiveness of systemic antibiotic therapy in conjunction with standard topical treatment for psoriatic patients with concomitant streptococcal throat infection. The research involved 115 patients with mild‐to‐moderate psoriasis, clinically assessed using the Psoriasis Area and Severity Index (PASI). Patients with active streptococcal infection were administered adjunctive systemic antibiotic therapy along with standard local treatment for psoriasis, while psoriasis patients without evidence of infection received the local topical treatment only. Streptococcal infections were more common in psoriasis patients compared to healthy controls. A group of psoriasis patients with active streptococcal throat infections, treated with antibiotics in addition to standard topical psoriasis therapy, did not show any difference in PASI score reduction compared to those without evidence of active infection. While our study did not show a statistically significant reduction in PASI scores in psoriasis patients with streptococcal throat infections treated with antibiotics, it highlights the complex interaction between infection and psoriasis. Larger studies with longer follow‐up may better clarify this relationship, contributing to stronger evidence for or against the use of antibiotics in managing psoriasis triggered by streptococcal infections.

Background: The clinical, epidemiological and immunopathological profiles of atypical forms of pemphigus remain only partially known. Objectives: To define the clinical, epidemiological and immunological characteristics, therapies and outcomes in patients with atypical pemphigus variants. Methods: This was a 14-year multicentre retrospective observational study (VARIANT_P) on atypical variants of pemphigus across Italy. We collected demographic, immunopathological and clinical data, as well as information on comorbidities and prescribed treatments. Results: We enrolled 61 patients [female/male sex ratio 1.77; 13 paraneoplastic pemphigus (PNP), 26 IgA pemphigus (PIgA), 22 pemphigus herpetiformis (PH)]. The median ages at onset and diagnosis were 70.6 (range 43.1–86.8) and 71.1 (range 46.9–86.9) for PNP; 62.2 (range 3.8–81.0) and 63.6 (range 4.0–82.4) for PIgA; and 49.4 (range 5.4–84.4) and 52.3 (range 5.9–85.9) for PH, respectively. The median diagnostic delay was 3.0 (range 0.0–45.6) months for PNP, 9.5 (range 1.0–140.0) months for PIgA and 2.0 (range 0–30.4) months for PH. The mortality rate was 55% (6/11) for PNP, 4% (1/26) for PIgA and 6% (1/17) for PH. Cutaneous involvement was present in all patients with PIgA and PH, and in 83% (10/12) of the patients with PNP. In contrast, oral mucosal involvement was observed in all patients with PNP with data (n = 12), but only in 8% (2/26) of those with PIgA and 21% (4/19) of those with PH. Histology, direct immunofluorescence, indirect immunofluorescence and enzyme-linked immunosorbent assay data demonstrated variable concordance with previously known data. Comorbidities included mainly solid malignancies for people with PNP, whereas cardiovascular and metabolic diseases were the most prevalent for those with PIgA and PH. Treatment mostly relied on systemic steroids and rituximab. Conclusions: The VARIANT_P study contributes to data collection relating to atypical pemphigus variants in order to promote the development of specific therapeutical guidelines in the future.