Urticaria is an inflammatory skin disorder that may occur in isolation or associated with angioedema and/or anaphylaxis. Clinically, it is characterized by the presence of smooth, erythematous or blanching, itchy swelling, called wheals or hives, which greatly vary in size and shape and last less than 24 h before fading to leave normal skin. Urticaria is the consequence of mast-cell degranulation that can be caused by immunological or non-immunological mechanisms. From a clinical point of view, many skin conditions can mimic urticaria and their recognition is mandatory for a correct management and therapeutic approach. We have reviewed all of the main relevant studies which addressed differential diagnosis of urticarial, published until December 2022. The National Library of Medicine PubMed database was used for the electronic research. The present review offers a clinical narrative overview, based on the available literature, of the principal skin disorders that can be misdiagnosed as urticaria (mainly autoinflammatory or autoimmune disorders, drug-induced reactions, and hyperproliferative diseases). The aim of this review is to provide clinicians a useful tool for correctly suspecting and identifying all of these conditions.

OX40 is a co-stimulatory immune checkpoint molecule that promotes the activation and the effector function of T lymphocytes through interaction with its ligand (OX40L) on antigen-presenting cells. OX40–OX40L axis plays a crucial role in Th1 and Th2 cell expansion, particularly during the late phases or long-lasting response. Atopic dermatitis is characterized by an immune dysregulation of Th2 activity and by an overproduction of proinflammatory cytokines such as interleukin (IL)-4 and IL-13. Other molecules involved in its pathogenesis include thymic stromal lymphopoietin, IL-33, and IL-25, which contribute to the promotion of OX40L expression on dendritic cells. Lesional skin in atopic dermatitis exhibits a higher level of OX40L+-presenting cells compared with other dermatologic diseases or normal skin. Recent clinical trials using antagonizing anti-OX40 or anti-OX40L antibodies have shown symptom improvement and cutaneous manifestation alleviation in patients with atopic dermatitis. These findings suggest the relevance of the OX40–OX40L axis in atopic dermatitis pathogenesis.

Objective: A recently proposed self‐assessment questionnaire aimed at diagnosing sensitive skin provided promising results in a relatively small population. The main objectives were: (i) to assess the reliability of the aforementioned questionnaire in a larger population and verify the cut‐off score previously found to predict skin sensitivity (defined as positivity to LAST, lactic acid stinging test) and (ii) to define a formula that yields the probability of a positive LAST result.Methods: Adult volunteers were included in this observational, cross‐sectional, extended study. Both LAST‐positive subjects, who were considered as having sensitive skin (‘patients’) and negative ones (‘controls’) completed the questionnaire, which concerned sensitivity to possible triggers of unpleasant skin sensations in real life. A cumulative score (questionnaire‐based skin sensitivity score, 0–10) was calculated from the sum of all items.Results: Three hundred and sixty‐four subjects were enrolled, 214 patients and 150 controls. The mean questionnaire‐based skin sensitivity score was significantly higher among patients than controls. Using two different methods, cut‐off values of 4 and 5 were defined for the identification of LAST‐positive subjects, with 76.6% and 72.8% accuracy, respectively. Scores below 4 or above 5 showed a high (80% or better) negative or positive predictive value, respectively. The coefficients found that in multivariate analysis for each questionnaire item, gender and age allowed us to calculate the probability of LAST positivity with higher precision taking into account the ‘relative weight’ of each factor.Conclusion: With small variations in the results, the self‐assessment questionnaire confirmed its reliability for diagnosing sensitive skin in clinical practice.

Article: Does sensitive skin lie in epidermal barrier impairment or abnormalities? Results from an observational study assessing biophysical parameters - Italian Journal of Dermatology and Venereology 2024 Apr 18 - Minerva Medica - Journals

Objective: The phenomenon of topical corticosteroid (TC) phobia (TCP) poses a challenge to the adherence of patients requiring prolonged treatments, particularly those with conditions like atopic dermatitis. Nonadherence to treatment significantly contributes to the inadequate control of diseases. This study aimed to evaluate TCP among women suffering from vulvar lichen sclerosus (VLS) and its potential impact on treatment adherence and therapeutic outcomes. Materials and Methods: This observational, prospective study involved adult patients who received their first histological diagnosis of VLS and underwent a 12-week corticosteroid treatment regimen at the authors’ Vulva Unit between June 2022 and September 2023. All participants completed the validated TOPICOP questionnaire, which assesses concerns, worries, and beliefs regarding TC usage. Baseline and 12-week control visit assessments were conducted to evaluate subjective and objective parameters of VLS. Patient adherence to treatment was monitored through diary entries. Results: Among the 50 patients included (with a mean age of 64.9 ± 13.5 years), more than half (58%) had prior experience with TC treatments and 10.3% had used corticosteroids for vulvar symptoms without a precise diagnosis. The median global TOPICOP score was 19.4% (interquartile range = 5.6–36.1), with a corresponding median value of 7.0 (interquartile range = 2.0–13.0). A total of 41 patients (82.2%) adhered to the study treatment, which proved highly effective in alleviating symptoms and improving signs of VLS. Multivariate analysis revealed that neither treatment adherence nor effectiveness were significantly associated with the level of TCP. Conclusions: Among the authors’ VLS patients, TCP was relatively low and did not negatively impact treatment adherence to corticosteroids. Moreover, TCP did not influence the effectiveness of TC therapy, as it did not affect adherence.