Evidence suggests a protective role for several nutrients and foods in the maintenance of skin function. Nevertheless, all the requests for authorization to use health claims under Article 13(5) in the framework of maintenance of skin function presented to the European Food Safety Authority (EFSA) have received a negative opinion. Reasons for such failures are mainly due to an insufficient substantiation of the claimed effects, including the choice of inappropriate outcome variables (OVs) and methods of measurement (MMs). The present paper reports the results of an investigation aimed at collecting, collating and critically analyzing the information with relation to claimed effects (CEs), OVs and MMs related to skin health compliance with Regulation 1924/2006. CEs, OVs and MMs were collected from both the EFSA Guidance document and from the authorization requests of health claims under Article 13(5). The critical analysis of OVs and MMs was based on a literature review, and was aimed at defining their appropriateness (alone or in combination with others) in the context of a specific CE. The results highlight the importance of an adequate choice of OVs and MMs for an effective substantiation of the claims.

Introduction: Psoriasis (PSO) and atopic dermatitis (AD) have traditionally been considered distinct diseases, respectively, mediated by T-helper 1 (Th1) and the T-helper 2 (Th2) immune pathway. In recent years, there has been a growing body of evidence highlighting an overlap between the two conditions, such as Asian AD, pediatric PSO, or “psoriasis dermatitis/PSOREMA”. Moreover, psoriasis dermatitis can be induced by therapeutic interventions. For instance, anti-IL-4/IL-13 monoclonal antibodies, commonly used to treat AD, can induce psoriasiform reactions by inhibiting the Th2 pathway, thereby unmasking Th1/Th17-driven PSO. Conversely, anti-TNFα and anti-IL-17 therapies, effective for PSO, may induce eczematous reactions promoting a switch toward Th2-driven inflammation. Janus Kinase Inhibitors (JAK-i) and IL-23 antagonists may represent valid therapeutic options for managing psoriasis dermatitis. JAK-i exert broader immunomodulatory effects, inhibiting both Th1 and Th2 pathways; however, they require careful monitoring due to potential adverse events. In contrast, IL-23 antagonists specifically suppress the IL-23/IL-17 axis inhibiting the p19 subunit of IL-23 and could represent a safer option for patients with psoriasis dermatitis. Materials and Methods/Results: We present a series of five cases of psoriasis dermatitis, including both patients who had the condition from the onset and those who developed it during treatment, with tailored therapeutic strategies based on individual patient profiles, comorbidities, and the specific characteristics of their overlapping disease presentation. Conclusion: JAK-i and IL-23 antagonists are both valid therapeutic options for managing psoriasis dermatitis, but with different immunomodulatory effects and safety profiles. Future research should focus on a better understanding of the immune pathway and identifying specific biomarkers of psoriasis dermatitis, to optimize therapeutic strategies.

Pemphigus vulgaris (PV) is a rare, potentially lethal blistering disease typically occurring in adulthood and characterized by autoantibodies directed against mucocutaneous desmosomal proteins. Clinically, flaccid vesicles, bullae and erosions after breakage are the main clinical features. According to the literature, the incidence of PV is rare in the pediatric population, ranging from 1 to 4% of reported cases. We describe an interesting case of a 12-year-old boy with severe PV that was referred to our university hospital for a mucocutaneous disease resistant to anti-infective therapy. Following the appearance of bullous lesions on the skin, antibody screening for autoimmune diseases showed positivity for PV and corticosteroid therapy was started. In view of the numerous adverse effects, we decided to set up biological therapy with rituximab, which was interrupted due to the onset of an urticarial reaction. Further second-line therapies were therefore attempted, with only a partial response. For this reason, a desensitizing therapy with rituximab was decided, thus allowing a clear improvement in the clinical picture and quality of life of the patient. To the best of our knowledge, this is the first report of a child with severe PV resistant to conventional therapies and with an urticarial reaction to rituximab. This case highlights that despite PV being extremely rare in the pediatric population, this diagnosis should not be entirely discounted. In case of severe clinical manifestations, rituximab represents a valid option in children and desensitization tests should be recommended in the presence of hypersensitivity to this drug.