Hidradenitis suppurativa and Langerhans cell histiocytosis are rare disorders that can reveal similar clinical manifestations, making differential diagnosis difficult. A definitive diagnosis requires biopsy and histological confirmation in suspicious cases. The complex pathophysiology of these diseases has still not been understood, therefore the treatment is still a challenge for physicians. It is seen with predilection in the intertriginous areas of the body, predominantly in the axillary region, rarely requiring a surgical procedure. However perineal, perianal, and gluteal HS usually necessitates some form of surgical treatment. Langerhans cell histiocytosis (histiocytosis X) is a very rare systemic disease manifested by clonal cell proliferation of histiocytic-dendritic nature, with pseudonodular manifestation that deeply infiltrates the hypodermis and ulcerates the epidermis on the surface. Langerhans cells are dendritic, antigen-presenting cells localized in the suprabasal regions of the squamous epithelium of the skin and mucous membranes, which help regulate the immune system. In this report, we present our experience with extensive gluteal, perineal, and perianal hidradenitis suppurativa and Langerhans cell histiocytosis cases, including our treatment methods and outcomes.

Background: Hidradenitis Suppurativa (HS) is characterized by inflamed lesions that appear in apocrine rich flexural areas. Although studies have reported clinical and epidemiological data from western countries, data from the Middle East are scarce. The aim of this study is to characterize the differences in the clinical characteristics of patients with HS of Arab and Jewish ancestry and to review the clinical characteristics, the course of the disease, the comorbidities and the response to treatment. Methods: This is a retrospective study. We collected clinical and demographic data from patient files at the Rambam Healthcare Campus dermatology clinic – a tertiary hospital located at the north of Israel. between 2015-2018. Our results were compared to those of a previously published Israeli control group registered in clalit health services. Results: Of the 164 patients with HS, 96 (58.5%) were men and 68 (41.5%) were women. The average age at diagnosis was 27.5 years and the latency between the onset and diagnosis of the disease was 4 years. we found a higher adjusted prevalence of HS in Arab patients (56%) than in their Jewish counterparts (44%). Gender, smoking and obesity, as well as axilla and buttock lesions, were risk factors for severe HS, with no differences between ethnicities. No differences were documented in comorbidities and in response to Adalimumab, with a high overall response rate of 83%. Conclusions: Our findings revealed differences between Arab and Jewish patients with HS in terms of incidence and gender predominance, while no differences were documented in comorbidities and response to Adalimumab.

Hidradenitis suppurativa (HS) is a chronic skin disease characterized by painful, recurrent abscesses, nodules, and scarring, primarily in skin folds. The exact causes of HS are multifactorial, involving genetic, hormonal, and environmental factors. It is associated with systemic diseases like metabolic syndrome and inflammatory bowel disease. Genetic studies have identified mutations in the γ-secretase complex, which affects Notch signaling pathways critical for skin cell regulation. Despite its high heritability, most HS reported cases do not follow a simple genetic pattern. In this article, we performed a whole-exome sequencing (WES) on a cohort of 100 individuals with HS and we provide a comprehensive review of the variants known to be described or associated with HS, referencing 91 of them in the γ-secretase and 78 in other genes involved in the Notch pathway, keratinization, or immune response. From this new genetic analysis, we add ten new variants to these catalogs.

Introduction & Objectives: Blood cells-(BC)count derived parameters have been inves-tigated in systemic inflammation, cancer, and various cutaneous diseases. Little is known about their usefulness in trichology, especially as prognostic and therapeutic biomarkers. We conducted a retrospective study on patients with not-cicatricial alopecia to assess differences in BC-count. Materials & Methods: Patients with alopecia areata (AA), telogen effluvium (TE), androgenic alopecia (AGA), psoriasis and hidradenitis suppurativa (HS) were included in the study. Baseline complete BC-count and derived parameters (i.e. NLR, PLR, MLR, SII; PIV) were recorded and analyzed for each patient and at different timepoints for AA patients on systemic agents. Results: 170 patients fulfilled inclusion criteria. BC-count and derived values were similar across the not-cicatricial alopecia groups, while general differences were observed compared to psoriasis and HS. TE displayed a closer inflammatory signature to psoriasis with respect to CRP, NLR, MLR, SII and PIV. We also found a significant reduction in RBCs in severe versus patchy-AA and an increase of SII in acute versus chronic AA. Modulation of platelet number and volume could be used as therapeutic marker in AA. Conclusions: In our experience, the BC-count and its derived parameters could represent potential tools in AA and TE.