Extensive blistering is a predictor for severe complications in children with mastocytosis

Challenges in the Diagnosis of Cutaneous Mastocytosis

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.

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.

Dermoscopic Features of Different Forms of Cutaneous Mastocytosis: A Systematic Review

The term mastocytosis refers to a heterogeneous group of disorders characterised by accumulation of clonal mast cells in different organs, most commonly in the skin. Little is known about the role of dermoscopy in the diagnostics of mastocytosis. To date, no systematic review on the dermoscopic features of cutaneous mastocytosis has been performed. The aim of this study was to summarise the current knowledge in the field as well as to identify the knowledge gaps to show possible directions for further studies, based on a systematic search of PubMed, Scopus, and Web of Science databases and related references published before 3 January 2022. Dermoscopic features, type of dermoscope, polarisation mode, magnification, and number of cases were analysed. In total, 16 articles were included in this review (3 case series and 13 case reports), analysing 148 patients with different variants of cutaneous mastocytosis; all of the studies analysed had a low level of evidence (V). The main dermoscopic features of urticaria pigmentosa included brown structureless areas, brown lines arranged in a network, and linear vessels distributed in a reticular pattern, with this last finding also being typical of telangiectasia macularis eruptiva perstans. The presence of either circumscribed yellow structureless areas or diffuse yellowish background was a constant pattern of mastocytoma, while nodular, pseudoangiomatous xanthelasmoid, and plaque-type mastocytosis were typified by light-brown structureless areas and/or pigment network, though the first two variants also showed yellow/yellow-orange structureless areas. Finally, pigmented streaks of radial distribution surrounding hair follicles were described to be a pathognomonic dermoscopic feature of pseudoxanthomatous mastocytosis. Although this review shows that the various clinical forms of cutaneous mastocytosis may feature diagnostic dermoscopic clues, it also underlines the need for further investigation as several relevant data are missing, including evaluation of dermoscopic pattern according to anatomical locations or “lesion age”, studies on rare mastocytosis variants, evaluation of the prognostic role of dermoscopy in the context of systemic involvement, and comparative analyses with common clinical mimickers.

Drugs and Vaccines Hypersensitivity in Children with Mastocytosis

Mastocytosis, a heterogeneous mastcell disease, include three different entities: cutaneous mastocytosis, systemic mastocytosis (SM) and mast-cell sarcoma. Tryptase levels can differentiate cutaneous mastocytosis from SM. In mastocytosis, quick onset drug hypersensitivity reactions (DHRs) that are facilitated by mastcell mediators, are investigated in adults. Due to the limited number of children with mastcell disease and increased serum tryptase levels, the role of drugs in this age group is less studied. In this review, we critically assessed relevant papers related with immediate DHRs in children with mastocytosis and discuss practical issues of the management. In childhood mastocytosis, anaphylaxis is frequently idiopathic, and elevated level of basal tryptase, and high burden of disease may increase the risk. Among drugs, antibiotics, NSAIDs and opioids can potentially induce anaphylaxis, anyway avoidance should be recommended only in case of previous reactions. Moreover, vaccinations are not contraindicated in patients with mastocytosis. The risk of severe systemic reactions after drugs intake seems to be extremely low and in general lower in children than in adults. Anyway, studies on this topic especially focusing on children, are missing to state final recommendations.

Mediator-Related Symptoms and Anaphylaxis in Children with Mastocytosis

Mastocytosis is characterized by the pathological accumulation of mast cells (MC) in various organs. In these patients, MC may degranulate and thereby contribute to clinical symptoms, especially when a concomitant allergy is present. However, MC activation can not only be induced by high-affinity receptors for IgE, but also by anaphylatoxins, neuropeptides, IgG immune complexes, complement-components, drugs, products of bacteria or parasites, as well as physical factors such as heat, cold, vibration, stress, sun, or physical effort. Symptoms due to mediators released by activated MC may develop in adults suffering from systemic mastocytosis, but also evolve in children who usually have cutaneous mastocytosis (CM). Clinically, CM is otherwise characterized by typical brown, maculopapular skin lesions or mastocytoma associated with a positive Darier's sign. Pruritus and flushing are common and blistering may also be recorded, especially in diffuse CM (DCM). Pediatric patients with mastocytosis may also have gastrointestinal, respiratory, and neurologic complaints. Although anaphylaxis is not a typical finding, pediatric patients with massive skin involvement and high tryptase levels have a relatively high risk to develop anaphylaxis. This paper reviews MC mediator-related symptoms and anaphylaxis in children with mastocytosis, with special emphasis on risk factors, triggers, and management.

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.

Cutaneous mastocytosis: A dermatological perspective

Mastocytosis is a rare disease characterised by expansion and collection of clonal mast cells in various organs including the skin, bone marrow, spleen, lymph nodes and gastrointestinal tract. The prevalence of mastocytosis has been estimated to be one in 10 000, while the estimated incidence is one per 100 000 people per year. Cutaneous mastocytosis is classified into (i) maculopapular cutaneous mastocytosis, also known as urticaria pigmentosa; (ii) diffuse cutaneous mastocytosis; and (iii) mastocytoma of the skin. In adults, cutaneous lesions are usually associated with indolent systemic mastocytosis and have a chronic evolution. Paediatric patients, on the contrary, have often cutaneous manifestations without systemic involvement and usually experience a spontaneous regression. Diagnosis of cutaneous mastocytosis may be challenging due to the rarity of the disease and the overlap of cutaneous manifestations. This short review describes pathogenesis and clinical aspects of cutaneous mastocytosis with a focus on diagnosis and currently available therapies.

Adverse reactions to drugs and biologics in patients with clonal mast cell disorders: A Work Group Report of the Mast Cells Disorder Committee, American Academy of Allergy, Asthma & Immunology

Providers caring for patients with mastocytosis are tasked with the decision to consider therapeutic options. This can come with some trepidation because information available in the public domain lists numerous mast cell (MC) activators based on data that do not discriminate between primates, rodents, and MC lines; do not consider dosage; and do not take into account previous exposure and resultant clinical findings. This being said, there is support in the literature for an enhanced MC response in some patients with mastocytosis and in cases in which there is a greater incidence of adverse reactions associated with certain antigens, such as venoms and drugs. Thus this report provides a comprehensive guide for those providers who must decide on therapeutic options in the management of patients with clonal MC disease.

Pediatric Expression of Mast Cell Activation Disorders

Mast cell activation disorders is a term proposed to cover diseases and conditions related to activation of mast cells and effects of mast cell mediators. In its broadest sense, the term encompasses a wide range of diseases from allergic asthma to rhinoconjunctivitis, urticaria, food allergy, anaphylaxis, mastocytosis, and other conditions where MC activation is contributing to the pathogenesis. This article focuses on clinical presentations, challenges, and controversies in pediatric mastocytosis and gives an overview of current knowledge and areas in need of further research.

Cutaneous Mastocytosis in Adults and Children: New Classification and Prognostic Factors

The skin is one of the most frequent tissues affected in patients with mastocytosis, but cutaneous lesions are highly heterogeneous in shape, size, color, number, localization, and distribution. The World Health Organization recognizes 3 subtypes of cutaneous mastocytosis (CM): maculopapular CM (MPCM), diffuse CM, and mastocytoma of skin. An international task force of experts in mastocytosis has recently proposed subdividing MPCM into monomorphic and polymorphic, which could predict the duration of the disease in children. More research is warranted to develop an improved classification of CM that ideally should incorporate robust factors with prognostic impact on disease behavior.

Mastocytosis and Anaphylaxis

This article updates current knowledge on epidemiology, risk factors, triggers, and management of anaphylaxis in patients with mastocytosis. Hyperactive mast cells and higher number of effector mast cells are speculated to facilitate anaphylaxis in this condition. In children, increased risk is limited to those with extensive skin involvement and high tryptase. In adults, manifestations of anaphylaxis are severe with high frequency of cardiovascular symptoms. Hymenoptera stings are the most common triggers for these reactions; however, idiopathic anaphylaxis and reactions to food or drugs occur. Patients with mastocytosis should be informed about risk of anaphylaxis and prescribing emergency self-medication and installing emergency preparedness before general anesthesia is considered.

Bullous mastocytosis in a 3-month-old infant

Mastocytosis is a rare myeloid neoplasm characterized by abnormal proliferation and accumulation of mast cells in one or more organ systems including the skin, bone marrow, liver, spleen, lymph nodes and gastrointestinal tract. An infant presenting with bullous lesions is an even rarer clinical presentation of cutaneous mastocytosis. The symptoms and complications are mostly in proportion to the mast cell degranulation in tissues. Management is focused on preventing and treating this event. We report a three-month-old infant with bullous mastocytosis to enhance awareness about this rare diagnosis.