Background: Mastocytosis is characterized by an accumulation of clonal mast cells (MCs) in tissues such as the skin. Skin lesions in mastocytosis may be clinically subtle or heterogeneous, and giving the correct diagnosis can be difficult. Methods: This study compiles personal experiences together with relevant literature, discussing possible obstacles encountered in diagnosing skin involvement in mastocytosis and cutaneous mastocytosis (CM). Results: The nomenclature of the term “CM” is ambiguous. The WHO classification defines CM as mastocytosis solely present in the skin. However, the term is also used as a morphological description, e.g., in maculopapular cutaneous mastocytosis (MPCM). This is often seen in systemic, as well as cutaneous, mastocytosis. Typical CM manifestations (MPCM), including mastocytoma or diffuse cutaneous mastocytosis (DCM), all share a positive Darier’s sign, and can thus be clinically recognized. Nevertheless, distinguishing monomorphic versus polymorphic MPCM may be challenging, even for experienced dermatologists. Less typical clinical presentations, such as MPCM with telangiectatic erythemas (formerly called telangiectasia macularis eruptiva perstans), confluent, nodular or xanthelasmoid variants may require a skin biopsy for histopathological confirmation. Because MC numbers in CM have a large overlap to those in healthy and inflamed skin, detailed histopathological criteria to diagnose mastocytosis in MPCM are needed and have been proposed. D816V KIT mutational analysis in tissue is helpful for confirming the diagnosis. Biomarkers allow the prediction of the course of CM into regression or evolution of the disease. Further diagnostic measures should screen for concomitant diseases, such as malignant melanoma, and for systemic involvement. Conclusions: Whereas in typical cases the diagnosis of CM may be uncomplicated, less typical manifestations may require specific investigations for making the diagnosis and predicting its course.

We appreciate the interest and reflections of Urbina and Benavides on our recent article published in Diagnostics and presentation of their two new patients

Background: Perineal nodular induration (PNI) is a benign proliferation of the soft tissue in the perineal region that is associated with saddle sports, especially road cycling. The etiology has not been conclusively clarified; however, repeated microtrauma to the collagen and subcutaneous fat tissue by pressure, vibration and shear forces is considered a mechanical pathomechanism. In this context, chronic lymphedema resulting in the development of fibrous tissue has been suggested as an etiological pathway of PNI. The primary aim of this study was to introduce and elucidate a novel operative technique regarding PNI that is assisted by indocyanine green (ICG). In order to provide some context for this approach, we conducted a comprehensive review of the existing literature. This dual objective aimed to contribute to the existing body of knowledge while introducing an innovative surgical approach for managing PNI. Methods: We reviewed publications relating to PNI published between 1990 and 2023. In addition to the thorough review of the literature, we presented our novel surgical approach. We described how this elaborate approach for extensive cases of PNI involves surgical excision combined with tissue doubling and intraoperative ICG visualization for exact lymphatic vessel obliteration to minimize the risk of recurrence based on the presumed context of lymphatic congestion. Results: The literature research yielded 16 PubMed articles encompassing 23 cases of perineal nodular induration (PNI) or cyclist’s nodule. Of these, 9 cases involved females, and 14 involved males. Conservative treatment was documented in 7 cases (30%), while surgical approaches were reported in 16 cases (70%). Notably, a limited number of articles focused on histopathological or radiological characteristics, with a shortage of structured reviews on surgical treatment options. Only two articles provided detailed insights into surgical techniques. Similarly to the two cases of surgical intervention identified in the literature research, the post-operative recovery in our ICG assisted surgical approach was prompt, meaning a return to cycling was possible six weeks after surgery. At the end of the observation period (twelve months after surgery), regular scar formation and no signs of recurrence were seen. Conclusion: We hope that this article draws attention to the condition of PNI in times of increasing popularity of cycling as a sport. We aimed to contribute to the existing body of knowledge through our thorough review of the existing literature while introducing an innovative surgical approach for managing PNI. Due to the successful outcome, the combination of tissue doubling, intraoperative ICG visualization and postoperative negative wound therapy should be considered as a therapeutic strategy in cases of large PNI.

Background: Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases, associated with itching, sleep disturbance, and impaired quality of life. Structured patient education can improve disease outcomes, but in-person programs are often unavailable in rural or underserved areas. Digital interventions may help overcome these barriers; however, their efficacy compared with routine care has not been evaluated. Objective: This study aims to assess whether a digitally delivered, interdisciplinary care concept (ADCompanion) is noninferior to routine, real-world care, as available in well-served areas, in reducing disease severity among patients with AD. Secondary objectives include effects on quality of life, pruritus, psychosocial burden, family well-being, and health care costs. Methods: This is a prospective, multicenter, 2-arm, 1:1 randomized noninferiority trial. Participants are stratified by age and disease severity. The intervention group receives standard therapy plus access to a digital platform with training modules and optional video consultations on skin care, nutrition, and psychosocial support. The control group receives routine care, optionally including face-to-face group training where available, and a basic app version for symptom tracking. The primary endpoint is physician-assessed disease severity (Scoring Atopic Dermatitis Index [SCORAD]) at 6 months; secondary endpoints include patient-reported outcomes, itch, quality of life, and disease-related costs. Results: Recruitment of 603 participants across 7 centers in Germany was completed. Data collection was finalized in June 2025. At the time of protocol submission (February 2026), data cleaning had been completed, and the statistical analysis plan was finalized; final results are expected to be published in 2026. Conclusions: This protocol describes a randomized trial designed to evaluate whether digitally delivered interdisciplinary care is noninferior to routine care for patients with AD. The findings of this study will inform the role of digital patient education as a complementary component within established care structures.