Current Challenges in the Diagnosis of Pediatric Cutaneous Mastocytosis.

Pediatric mastocytosis is mostly a cutaneous disease classified as cutaneous mastocytosis (CM), which is characterized by mast cell (MCs) accumulation in the skin and the absence of extracutaneous involvement. Based on the morphology of skin lesions, CM can be divided into three major forms: maculopapular CM (MPCM), diffuse CM (DCM) and mastocytoma of the skin. A positive Darier's sign is pathognomonic for all forms of CM. MPCM is the most common form, presenting with red-brown macules or slightly raised papules. Mastocytoma is characterized by solitary or a maximum of three nodular or plaque lesions. DCM is a rare, severe form which presents as erythroderma, pachydermia and blistering in the infantile period of the disease. CM is associated with MC mediator-related symptoms, most commonly including pruritus, flushing, blistering, diarrhea and cramping. Anaphylactic shock occurs rarely, mainly in patients with extensive skin lesions and a significantly elevated serum tryptase level. Childhood-onset MPCM and mastocytoma are usually benign diseases, associated with a tendency for spontaneous regression, while DCM is associated with severe mediator-related symptoms, an increased risk of anaphylaxis and, in some cases, underlying systemic mastocytosis (SM). In contrast to adults, SM is a rare finding in children, most commonly presenting as indolent SM. However, advanced SM sporadically occurs.

The Role of Mast Cells in the Induction and Maintenance of Inflammation in Selected Skin Diseases.

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.

Natural evolution in pediatric cutaneous mastocytosis: 10-year follow-up.

BACKGROUND: Mastocytosis is a heterogeneous group of myeloproliferative disorders characterized by accumulation of clonal mast cells in various tissues. The aim of this study was to determine the symptoms evolution and outcome after 10 years observation. METHODS: Fifty-five children with mastocytosis were included in the study group and monitored concerning mast cell mediator-related symptoms (MC MRSs) and clinical course of the disease for a period of ≥10 years. RESULTS: Patients presented with a maculopapular cutaneous form of mastocytosis (MPCM) (n = 47) and diffuse cutaneous mastocytosis (DCM) (n = 8). The complete remission (CR) of skin lesions occurred in 10.3% of children after 10 years observation; no remission (NR) was observed in 17.9% children. The CR of skin specific MC MRS occurred in 69.2% children with MPCM and in 14.3% with DCM. CONCLUSION: Most children with cutaneous mastocytosis (CM) eventually experience a major or partial regression of skin lesions, although complete regression before puberty is rare. The spontaneous remission of skin specific MC MRS is less frequent in children with DCM.

Molecular Background, Clinical Features and Management of Pediatric Mastocytosis: Status 2021.

Pediatric mastocytosis is a heterogeneous disease characterized by accumulation of mast cells in the skin and less frequently in other organs. Somatic or germline mutations in the KIT proto-oncogene are detected in most patients. Cutaneous mastocytosis is the most common form of the disease in children. In the majority of cases, skin lesions regress spontaneously around puberty. However, in few patients, mastocytosis is not a self-limiting disease, but persists into adulthood and can show signs of systemic involvement, especially when skin lesions are small-sized and monomorphic. Children with mastocytosis often suffer from mast cell mediator-related symptoms. Severe hypersensitivity reactions can also occur, mostly in patients with extensive skin lesions and blistering. In a substantial number of these cases, the triggering factor of anaphylaxis remains unidentified. Management of pediatric mastocytosis is mainly based on strict avoidance of triggers, treatment with H1 and H2 histamine receptor blockers, and equipment of patients and their families with epinephrine auto-injectors for use in severe anaphylactic reactions. Advanced systemic mastocytosis occurs occasionally. All children with mastocytosis require follow-up examinations. A bone marrow investigation is performed when advanced systemic mastocytosis is suspected and has an impact on therapy or when cutaneous disease persists into adulthood.

Refractory eosinophilic fasciitis successfully treated with infliximab: A case report.

Eosinophilic fasciitis is a rare connective tissue disease of unknown etiology. Therapeutic options include high-dose corticosteroids and other immunosuppressive drugs. We present a typical eosinophilic fasciitis case, which did not respond to first-line treatment, but improved remarkably after infliximab administration. This report demonstrates that in case of initial treatment failure, infliximab might be a relatively safe and effective way of eosinophilic fasciitis management.

New Approach to Paediatric Mastocytosis: Implications of KIT D816V Mutation Detection in Peripheral Blood.

is missing (Short communication).

Cutaneous mastocytosis treatment: strategies, limitations and perspectives.

Mastocytosis is a rare myeloproliferative disease, characterized by excessive proliferation and accumulation of mast cells in the tissues. In cutaneous mastocytosis (CM), mast cells infiltration is limited to the skin, whereas in systemic mastocytosis (SM) internal organs are involved. The first-line treatment in CM is antimediator therapy (mainly H1 and H2 antihistamines) and short-term topical corticosteroids. Phototherapy is the second-line therapy which may be considered when antihistamines do not produce the expected improvement. New therapeutic options include omalizumab and KIT-targeting agents. Although the disappearance of skin lesions has been reported as a result of cytoreductive therapies in SM, the use of potentially toxic drugs in CM is not recommended. In all adults with mastocytosis and in pediatric patients with severe CM, a persistently elevated serum tryptase level and anaphylaxis in medical history, equipping with epinephrine autoinjector for use in case of anaphylaxis is recommended.

The role of regulatory T cells and genes involved in their differentiation in pathogenesis of selected inflammatory and neoplastic skin diseases. Part II: The Treg role in skin diseases pathogenesis.

Regulatory FOXP3+ T cells (Tregs) constitute 5% to 10% of T cells in the normal human skin. They play an important role in the induction and maintenance of immunological tolerance. The suppressive effects of these cells are exerted by various mechanisms including the direct cytotoxic effect, anti-inflammatory cytokines, metabolic disruption, and modulation of the dendritic cells function. The deficiency of Treg cells number or function are one of the basic elements of the pathogenesis of many skin diseases, such as psoriasis, atopic dermatitis, bacterial and viral infections. They also play a role in the pathogenesis of T cell lymphomas of the skin (cutaneous T cell lymphomas - CTCL), skin tumors and mastocytosis. Here, in the second part of the cycle, we describe dysfunctions of Tregs in selected skin diseases.