Psoriasis vulgaris is a common inflammatory skin disease with still unknown pathogenesis. In recent years, genetic and environmental factors have been mentioned as the main causes. Among environmental factors, many researchers are trying to investigate the role of mental health and its importance in the development of many diseases. In the pathophysiology of psoriasis, the role of the interaction between the nervous, endocrine, and immune systems are often emphasized. So far, no one has clearly indicated where the pathological process begins. One of the hypotheses is that chronic stress influences the formation of hormonal changes (lowering the systemic cortisol level), which favors the processes of autoimmunity. In inflammatory skin conditions, mast cells (MCs) are localized close to blood vessels and peripheral nerves, where they probably play an important role in the response to environmental stimuli and emotional stress. They are usually connected with a fast immune response, not only in allergies but also a protective response to microbial antigens. Among many cells of the immune system, MCs have receptors for the hormones of the hypothalamic–pituitary–adrenal (HPA) axis on their surface. In this review, we will try to take a closer look at the role of MCs in the pathophysiology of psoriasis. This knowledge may give the opportunity to search for therapeutic solutions.

Under physiological conditions, skin mast cells play an important role as guardians that quickly react to stimuli that disturb homeostasis. These cells efficiently support, fight infection, and heal the injured tissue. The substances secreted by mast cells allow for communication inside the body, including the immune, nervous, and blood systems. Pathologically non-cancerous mast cells participate in allergic processes but also may promote the development of autoinflammatory or neoplastic disease. In this article, we review the current literature regarding the role of mast cells in autoinflammatory, allergic, neoplastic skin disease, as well as the importance of these cells in systemic diseases with a pronounced course with skin symptoms.

Introduction: Fish tank granuloma is a rare dermatitis caused by Mycobacterium marinum. Infection occurs through contact of damaged skin with water or aquatic animals infected with these bacteria. Aim: It is likely that skin infection caused by M. marinum transmitted from Clarias gariepinus has as yet not been reported in literature. Our case report is presumably the first publication. Dermatoscopy as a useful method in the diagnosis of skin infections caused by atypical mycobacteria. Our article presents new dermatoscopic features of fish tank granuloma. Case study: The case report applies to a 30-year old, white, Caucasian man referred because of a single, well-demarcated plaque measuring 2 × 4 cm, localized on third finger on left hand above proximal phalanx, without subjective symptoms. The diagnosis was confirmed by medical history, dermoscopy and histopathological examination. Patient was successfully treated with sulfamethoxazole and trimethoprim. Results and discussion: Due to the fact that M. marinum infection is uncommon, in case of clinical suspicion it is necessary to perform skin biopsy, culture and tissue PCR analysis. Knowledge about the opportunities and limitations of theses laboratory tests is pivotal to reasonable clinical decision-making. Conclusions: Dermoscopy is useful to make a diagnosis, but there are still too few accounts in literature. The correct diagnosis determines the effective treatment.