Diagnosis and treatment of cutaneous mastocytosis in children: practical recommendations

Relevant updates in systemic mastocytosis

Systemic Mastocytosis (SM) is a rare myeloproliferative neoplasm (MPN) that is characterized by a clonal proliferation of mast cells (MCs). The symptoms and clinical presentation of SM are the result of both MC proliferation as well as activation and degranulation, causing hyperactive and over-exaggerated hypersensitivity responses, as well as organ infiltration by pathogenic MCs. The clinical presentation and course of SM is varied and organ involvement can lead to significant morbidity and mortality in some cases. The subtypes of SM include indolent SM (ISM), smoldering SM (SSM), aggressive SM (ASM), SM with associated hematologic neoplasm (SM-AHN) and mast cell leukemia (MCL) and survival can range from normal in the case of ISM to months in MCL. The treatment of indolent forms of SM is largely focused on addressing symptom burden (B findings), while cytoreductive agents and more recently molecularly targeted agents are employed to reduce MC burden and reverse associated organ dysfunction (C findings). Although the pathogenesis of SM is multi-factorial, the acquisition of KIT D816 V is a relatively frequent mutational event and serves as the target of novel agents. The recent approval of midostaurin for the treatment of advanced SM has brought awareness to this disease and energized further drug development efforts. Expanding our understanding of the underlying molecular mechanisms of SM will continue to inform future therapeutic approaches.

Mastocytosis - pathogenesis, clinical manifestation and treatment

The term mastocytosis designates a group of rare disorders characterized by typical skin lesions, frequently associated episodes of anaphylaxis, and clinical symptoms related to the release of various mediators. Dermatologists/allergists are frequently the first to establish the diagnosis. The condition is based on clonal mast cell proliferation, usually in the skin or bone marrow and only rarely in the gastrointestinal tract or other tissues. In general, mastocytosis has a good prognosis in terms of life expectancy. Rare variants - including mast cell leukemia, aggressive mastocytosis, and the exceedingly rare mast cell sarcoma - require cytoreductive therapy. In cases associated with hematological neoplasms, the prognosis depends on the underlying hematologic disorder.

Mast cell disorders: From infancy to maturity

Mast cells are typically linked to immediate hypersensitivity and anaphylaxis. This review looks beyond this narrow role, focusing on how these cells have evolved and diversified via natural selection promoting serine protease gene duplication, augmenting their innate host defense function against helminths and snake envenomation. Plasticity of mast cell genes has come at a price. Somatic activating mutations in the mast cell growth factor KIT gene cause cutaneous mastocytosis in young children and systemic mastocytosis with a more guarded prognosis in adults who may also harbor other gene mutations with oncogenic potential as they age. Allelic TPSAB1 gene duplication associated with higher basal mast cell tryptase is possibly one of the commonest autosomal dominantly inherited multi-system diseases affecting the skin, gastrointestinal tract, circulation and musculoskeletal system. Mast cells are also establishing a new-found importance in severe asthma, and in remodeling of blood vessels in cancer and atherosclerotic vascular disease. Furthermore, recent evidence suggests that mast cells sense changes in oxygen tension, particularly in neonates, and that subsequent degranulation may contribute to common lung, eye, and brain diseases of prematurity classically associated with hypoxic insults. One hundred and forty years since Paul Ehrlich's initial description of "mastzellen," this review collates and highlights the complex and diverse roles that mast cells play in health and disease.

Diffuse Cutaneous Mastocytosis in a Child - a Case Report

Mastocytosis refers to a group of diseases characterized by a clonal proliferation and accumulation of mast cells in one or more tissues/organs with different clinical presentations. In children, limited cutaneous forms of mastocytosis are rather frequent, while systemic mastocytosis is rare. The diagnosis of cutaneous mastocytosis is based on clinical findings and histopathology. We present a patient who developed skin lesions at the age of 18 months. Clinical findings, confirmed by histopathology, were consistent with diffuse cutaneous mastocytosis. The follow-up period was 7 years. The treatment included oral antihistamines in combination with mast cell stabilizers, mild topical steroids and avoidance of friction. During the follow-up period, there were no signs of systemic involvement, and the quality of life was preserved, despite the large surface of affected skin. This case report should increase the awareness and knowledge of clinicians about this rare form of cutaneous mastocytosis in the pediatric population.

Pharmacotherapy of mast cell disorders

PURPOSE OF REVIEW

Mast cell disorders (MCDs) comprise mastocytosis and disorders referred to as mast cell activation syndrome and are caused by abnormal accumulation and/or activation of mast cells in tissues. Clinical signs and symptoms are protean; therefore, finding suitable treatment options for individual patients entails a challenge for clinicians. The purpose of this manuscript is to review the literature on the available therapeutic interventions in patients with MCD.

RECENT FINDINGS

Pharmacotherapy is mainly directed against the effects of mast cells and their mediators. The current recommendations are exclusively based on expert opinions due to the lack of controlled clinical trials. The targeted therapies aiming at blocking mutant KIT variants and/or downstream signaling pathways are currently being developed and may be considered in severely affected, therapy-refractory patients.

SUMMARY

There is currently no method for predicting the best available approach to control symptoms in individual patients with MCD. Therefore, a stepwise, individual-based approach in pharmacotherapy options appears to be most successful strategy and is recommended in all patients. The core component of the treatment in most patients is to control symptoms caused by mast cell mediator release, whereas cytoreductive therapies are mainly reserved for patients with advanced/aggressive systemic mastocytosis.

Topical pimecrolimus for paediatric cutaneous mastocytosis

BACKGROUND

Most cases of paediatric cutaneous mastocytosis (CM) occur before the age of 2 years, and regression occurs in only 67% of children. Given the absence of any specific therapy, CM is usually treated symptomatically. A few publications have reported the beneficial effect of calcineurin inhibitors for CM.

AIM

We sought to evaluate the clinical effectiveness and safety profile of topical pimecrolimus cream for the treatment of CM.

METHODS

We performed a retrospective study of all diagnosed cases of CM treated with topical pimecrolimus 1% cream between 2013 and 2015. All patients were evaluated in a paediatric dermatology unit of a tertiary medical centre. Epidemiological, clinical and treatment data, including effectiveness and safety, were reviewed.

RESULTS

In total, 18 children (11 male, 7 female; age range 3-42 months) with CM were evaluated. Of the 146 treated lesions, 39 (26.7%) disappeared and 98 (67%) faded or developed postinflammatory hyperpigmentation. Of the 119 papular lesions, 24 (16.4%) showed partial flattening and 56 (47%) became macular. Darier sign became negative in 14 (82%) of 17 patients. No topical or systemic complications were observed.

CONCLUSIONS

Topical therapy with pimecrolimus 1% cream should be considered in the treatment of CM.

In utero presentation of aggressive systemic mastocytosis in a neonate

Mastocytosis is a clinically heterogenous disease characterized by mast cell hyperplasia in skin, bone marrow and/or visceral organs. Cutaneous mastocytosis is more frequently observed in children, whereas indolent systemic mastocytosis is more commonly observed in adults. Aggressive systemic presentation, particularly of the neonate, is exceptionally rare. We present a rare case of congenital aggressive systemic mastocytosis. The patient was a 37-week-old male, born by caesarean section owing to hepatosplenomegaly and ascites diagnosed in utero, who exhibited extensive cutaneous and systemic manifestations of mastocytosis at birth. Mutation analysis of c-KIT identified D816V mutation in exon 17. Although initial bilateral bone marrow aspirates demonstrated no mast-cell infiltrates or haematological neoplasm, subsequent bone-marrow biopsies postmortem exhibited multifocal mast-cell aggregates. Clinical course was complicated by bacteraemia and cardiorespiratory failure, leading to death at 10 weeks.

Plasticity of immune system vs. memory therapy IST

BACKGROUND

Pharmacotherapy and immunotherapy are the main treatments for allergic diseases to inhalants.

OBJECTIVE

This study investigates whether to repeat short cycles of immunotherapy after 3 or 5 years the from interruption of the first therapeutic cycle, lasting 3-4 years, to maintain immune memory in individuals subjected to IST.

METHODS AND RESULTS

We have compared two groups, one of 452 patients who, after the first treatment for 3-4 years of IST, performed a cycle of four months after three and 10 years from the suspension, and a second group of 126 individuals who have performed only the IST treatment for 3-4 years. The best results were obtained in the first group.

CONCLUSIONS

These results are due to the immune system's plasticity, a very important concept in clinical practice.

Pathogenesis and Pathology of Mastocytosis

Systemic mastocytosis is a clonal disorder of mast cells that may variably present with characteristic skin lesions, episodes of mast cell mediator release, and disturbances of hematopoiesis. No curative therapy presently exists. Conventional management has relied on agents that antagonize mediators released by mast cells, inhibit mediator secretion, or modulate mast cell proliferation. Recent advances in the molecular understanding of the pathophysiology of systemic mastocytosis have provided new therapeutic considerations, including new and novel tyrosine kinase inhibitors.

The role of serum tryptase in the diagnosis and monitoring of pediatric mastocytosis: a single-center experience

INTRODUCTION

In children, cutaneous mastocytosis (CM) is considered to be a benign disease associated with mast cell mediator-related symptoms. However, systemic mastocytosis (SM) and anaphylaxis may also occur. Since the basal serum tryptase (bsT) level reflects mast cell burden, its determination is recommended in the diagnosis and follow-up.

AIM

To compare clinical presentation and the course of mastocytosis in children with normal and clearly elevated bsT levels as well as to assess its usefulness in the diagnosis and monitoring of the course of the disease.

MATERIAL AND METHODS

A retrospective analysis of 102 medical records of children with mastocytosis diagnosed and followed-up in the Gdansk Mastocytosis Center in 2014 was performed.

RESULTS

Maculopapular CM (MPCM) was diagnosed in 91 (89.22%) children, diffuse cutaneous mastocytosis (DCM) in 7 (6.86%) and mastocytoma in 4 (3.92%). The presence of flushing and bullous lesions was more frequent in children with bsT levels > 20 ng/ml in comparison with those who had bsT ≤ 20 ng/ml (p = 0.002 and p = 0.03, respectively). Anaphylaxis occurred in 2 MPCM children with bsT levels in normal ranges. In all of the 3 children with persistently and clearly elevated bsT levels, bone marrow biopsy revealed no mast cells infiltrates corresponding to SM.

CONCLUSIONS

Although mastocytosis children with clearly elevated bsT levels frequently develop mediator-related symptoms, the occurrence of anaphylaxis in this age group may be difficult to predict. In pediatric cases with suspected SM, the bsT level is one of the crucial parameters considered before the decision on bone marrow biopsy.

Solitary Mastocytoma of the Eyelid in an Adult Patient With Prolidase Deficiency

Prolidase deficiency and solitary mastocytoma of the eyelid are both exceedingly rare. Prolidase deficiency is an inherited connective tissue disorder that has systemic sequelae, such as intractable skin ulceration, poor wound healing, recurrent infections, and intellectual impairment. Cutaneous mastocytoma is an isolated, aberrant cutaneous aggregation of mast cells. A case of an adult with severe prolidase deficiency who developed cutaneous mastocytoma of the eyelid was presented. To the authors' knowledge, adult-onset solitary mastocytoma of the eyelid has never been reported previously.

Mast cell disorders: Kids are not just little people

Cutaneous mastocytosis is characterized by a pathologic increase in mast cells in the skin and may also involve extracutaneous organs. Symptoms, which are triggered by mast cell degranulation, vary depending on the burden of skin disease and the presence of extracutaneous disease. The clinical presentation, risk of systemic disease, pathogenesis, prognosis, and treatment options differ, largely depending on age at presentation. In the pediatric population, spontaneous remission is typical, generally by puberty, whereas in adults, progression is observed. Extracutaneous involvement and associated hematologic disorders seldom occur in children, as opposed to adults. It is therefore important to avoid overreliance on adult-based approaches to management of cutaneous mastocytosis in the pediatric population. We focus on differences in presentation, workup, and management of pediatric- and adult-onset cutaneous mast cell disorders.

Transient hypogammaglobulinaemia of infants in children with mastocytosis - strengthened indications for vaccinations

Mastocytosis is a disease caused by the accumulation of mast cells (MC) in the skin and/or in other tissues. Both the cutaneous form of the disease (CM) predominating in children and the systemic form (SM) typical for adults are associated with the occurrence of MC mediator-related symptoms. The release of mediators can be induced by physical stimuli and/or specific triggering factors. The routine vaccination program performed in the majority of children in infancy can be considered as an additional factor provoking exacerbation of CM. Conscious of the important role of MC in the innate immunity, we have analysed retrospective data concerning the levels of immunoglobulins, an adaptive factor, in a group of 74 infants and toddlers with CM. The values corresponding to transient hypogammaglobulinaemia of infants (THI) were found in 8 (10.81%) of cases. Classification of the antibody deficiency was done according to the working definitions for clinical diagnosis of primary immunodeficiency of the European Society of Immunodeficiencies (ESID) Registry - version May 11, 2015. Following the retrospective data, the final diagnosis of THI cannot be made due to the young age of the study group. The percentage may significantly exceed the published incidence of THI, i.e. about 0.11%. The results of our study may indicate, importantly, a higher incidence of THI in childhood-onset mastocytosis than in the general paediatric population and strengthen indications for vaccinations. In conclusion, we suggest that THI may be considered as a new aspect of paediatric mastocytosis that requires further investigation.

Current approach to cutaneous mastocytosis in childhood

Mastocytosis is a heterogeneous disorder characterized by clonal proliferation and accumulation of mast cells in one of more organs which may lead to different clinical pictures. Pathological increase and activation of mast cells in various tissues can cause different clinical pictures. Cutaneous mastocytosis limited to the skin is the most typical clinical picture observed in children and systemic mastocytosis is very rare in the pediatric age group. The diagnosis of cutaneous mastocytosis is based on clinical findings, but is often delayed due to lack of clinical awareness of the disease and lack of its consideration in the differential diagnosis. This article focuses on the current diagnosis, management and treatment of cutaneous mastocytosis in children in order to increase awareness about this issue.

[Cutaneous mastocytosis: A case report]

INTRODUCTION

Mastocytosis represents a group of diseases characterised by an excesive accumulation of mastocytes in one or multiple tissues. It can affect only the skin, or have a systemic involvement. It has a low prevalence, and the prognosis is benign in children.

OBJECTIVE

To report a case of urticaria pigmentosa as a subtype of cutaneous mastocytosis, and present a literature review focused on clinical findings, diagnosis and initial basic management.

CLINICAL CASE

A child of six months of age presenting with multiple blemishes and light brown papules located on the trunk, arms and legs. The symptoms were compatible with urticaria pigmentosa, and was confirmed by biopsy. Tests to rule out systemic involvement were requested. The patient was treated with general measures, education, and antihistamines, with favourable results.

CONCLUSIONS

Cutaneous mastocytosis is a rare disease with a good prognosis. In childhood general measures and education are usually enough to obtain favourable results. Histamine H1 antagonists are the first line drug treatment.

Update on Mastocytosis (Part 1): Pathophysiology, Clinical Features, and Diagnosis

Mastocytosis is a term used to describe a heterogeneous group of disorders characterized by clonal proliferation of mast cells in various organs. The organ most often affected is the skin. Mastocytosis is a relatively rare disorder that affects both sexes equally. It can occur at any age, although it tends to appear in the first decade of life, or later, between the second and fifth decades. Our understanding of the pathophysiology of mastocytosis has improved greatly in recent years, with the discovery that somatic c-kit mutations and aberrant immunophenotypic features have an important role. The clinical manifestations of mastocytosis are diverse, and skin lesions are the key to diagnosis in most patients.

H1-antihistamines for primary mast cell activation syndromes: a systematic review

BACKGROUND

Primary mast cell activation syndromes (MCAS) are a group of disorders presenting with symptoms of mast cell mediator release.

OBJECTIVES

To assess the effectiveness and safety of orally administered H1 -antihistamines in the treatment of primary MCAS compared with placebo and other pharmacologic treatments.

METHODS

We systematically searched five databases and three trial repositories and contacted an international panel of experts to identify published and unpublished trials.

RESULTS

A total of 36 potentially relevant studies were identified. Of these, five crossover trials, enrolling a total of 71 patients (63 adults), met the eligibility criteria. All five of these studies were judged to be at moderate or high risk of bias. Two studies compared an H1 -antihistamine with placebo, two compared two different H1 -antihistamines, and one study compared H1 - and H2 -antihistamines with oral cromolyn sodium. Four of the five randomized controlled trials were historic (reported from 1983-1993), small (enrolling 8-15 patients), and used agents and/or dosing regimens that are now less commonly used in clinical practice (i.e. azelastine, chlorpheniramine, hydroxyzine, and ketotifen). The fifth trial, which enrolled 33 adults with cutaneous and systemic mastocytosis found 4 weeks of treatment with the second-generation H1 -antihistamine rupatadine, compared with placebo, resulted in significant improvements in quality of life, symptom control (itching, wheals and flares, flushing, tachycardia, and headache, but not gastrointestinal symptoms), and reduction in itching and whealing after standardized skin provocation to elicit Darier's sign.

CONCLUSIONS

There is an urgent need for large, well-designed, double-blind, placebo-controlled randomized trials investigating the effectiveness, cost-effectiveness, and safety of second-generation H1 -antihistamines in treatment of primary MCAS.

Transglutaminase 2 expressed in mast cells recruited into skin or bone marrow induces the development of pediatric mastocytosis

BACKGROUND

Mastocytosis is characterized by a pathological increase in mast cells in organs such as skin and bone marrow. Transglutaminase 2 (TG2) expressed in mast cells contributes to allergic diseases, but its role in mastocytosis has not been investigated. This study aimed to investigate whether TG2 contributes to pediatric mastocytosis.

METHODS

Serum, various skin tissues or bone marrow (BM) biopsy and aspirates were obtained from pediatric normal control or patients with indolent systemic mastocytosis (SM), mastocytoma, and urticaria pigmentosa (UP). Tryptase, individual cytokines, leukotriene C4 (LTC4 ), and TG2 activity in the serum were determined by enzyme-linked immunosorbent assay, mast cell population by May-Grünwald-Giemsa, CD 117 by immunofluorescence, cell surface molecules by Western blot, and colocalization of c-kit and TG2 or IL-10-expressing cells, CD25, and FOXP3 by immunohistochemistry.

RESULTS

Infiltration of CD25(+) CD117(+) CD2(-) mast cells into BM and scalp/trunk/ear dermis; expression of FcεRI, tryptase, c-kit, FOXP3, CCL2/CCR2, and vascular cell adhesion molecule-1; and colocalization of c-kit and TG2 were enhanced in patient's skin tissues or BM, particularly SM, but colocalization of c-kit and IL-10-expressing cells was decreased vs. normal tissues. Amounts of LTC4 and inflammatory cytokines, expression of tryptase or TG2 activity were increased in patient's serum, BM aspirates, or ear/scalp skin tissues, respectively, vs. normal persons, but IL-10 level was decreased.

CONCLUSION

The data suggest that mast cells, recruited in the skin and BM by CCL2/CCR, may induce the development of pediatric mastocytosis through reducing IL-10 due to upregulating TG2 activity via transcription factor nuclear factor-κB. Thus, TG2 may be used in diagnosis of pediatric mastocytosis, particularly SM.

Assessment of clinical findings, tryptase levels, and bone marrow histopathology in the management of pediatric mastocytosis

BACKGROUND

The management of children with pediatric mastocytosis poses a challenge. This is because there is limited information as to the application of clinical and laboratory findings and bone marrow histopathology as they relate to medical intervention and communication.

OBJECTIVE

We sought to examine clinical aspects of pediatric mastocytosis in relationship to serum tryptase levels and bone marrow pathology to provide practical guidance for management.

METHODS

Between 1986 and 2012, 105 children were evaluated at the National Institutes of Health. Organomegaly was confirmed by means of ultrasound. Baseline tryptase levels and at least 1 subsequent tryptase measurement was available in 84 and 37 of these children, respectively. Fifty-three children underwent a bone marrow examination. These data were used to examine relationships between clinical findings, tryptase levels, and marrow histopathology.

RESULTS

In patients with high tryptase levels and severe mediator symptoms, all with organomegaly had systemic disease, and none without organomegaly had systemic disease. Serum tryptase levels differed significantly between patients with urticaria pigmentosa and those with diffuse cutaneous (P < .0001) and systemic mastocytosis (P < .0001) and in all 3 categories versus control subjects (P < .0001). Tryptase levels and symptoms decreased over time in most patients, and tryptase levels correlated with bone marrow mast cell burden in patients with systemic mastocytosis (P < .0001). There was a significant relationship between clinical resolution and the percentage decrease in tryptase levels (P = .0014).

CONCLUSIONS

The majority of children experienced major or complete disease resolution (57%), whereas the remainder exhibited partial improvement. Organomegaly was a strong indicator of systemic disease. Serum tryptase levels furthered classification and reflected clinicopathologic findings, while sequential tryptase measurements were useful in supplementing clinical judgment as to disease course.

Cutaneous Mastocytosis with Persistent Blistering: Successful Treatment with Methylprednisolone and 3-Year Follow-Up Management

Background

Mastocytosis is a rare disorder with diverse clinical manifestations. In cutaneous mastocytosis the mast cell infiltration is limited to the skin, but is often associated with systemic symptoms due to the release of mast cell mediators.

Case Report

We report a 6-month-old male infant who had skin lesions of various morphologies (macules, papules, plaques, and nodules) and sizes, persistent blistering and frequent flushing episodes for half a year. Vital signs and physical examinations were unremarkable. No abnormalities in the laboratory tests were found except for a serum tryptase level (STL) of 11.8 ng/ml. The histological and immunohistochemical examinations confirmed the diagnosis of cutaneous mastocytosis. The patient was first treated with methylprednisolone, oral levocetirizine, and topical fusidic acid/betamethasone cream. Subsequently the treatment was tapered and stopped within 9 weeks. The child’s symptoms improved and were successfully controlled with intermittent courses of ketotifen and topical hydrocortisone over 3 years.

Conclusion

Childhood cutaneous mastocytosis usually has a favorable prognosis, but in some cases the disease can progress with skin manifestations necessitating a more active systemic and topical treatment.

Electronic supplementary material

The online version of this article (doi:10.1007/s13555-015-0073-6) contains supplementary material, which is available to authorized users.

Oxidative stress markers are increased in patients with mastocytosis

BACKGROUND

Mastocytosis is characterized by clonal proliferation of mast cells limited to the skin (cutaneous mastocytosis: CM and mastocytosis in the skin: MIS) and/or involving internal organs (systemic mastocytosis: SM). Oxidative stress occurring in various inflammatory and neoplastic disorders causes molecular damage with the production of advanced oxidation protein products (AOPPs) and advanced glycation end products (AGEs). We evaluated these markers of oxidative stress in patients with CM/MIS and SM and correlated their levels with the presence of symptoms related to mast cell activation.

METHODS

Serum levels of AOPPs and AGEs in 34 patients with mastocytosis (23 CM/MIS and 11 SM) and 27 healthy controls were measured by spectrofluorimetric and spectrophotometric methods. Serum tryptase levels were measured by immunofluorescence.

RESULTS

Serum AOPPs, but not AGEs, were significantly higher in patients with mastocytosis as compared to healthy controls. While serum tryptase levels were higher in patients with SM as compared to those with CM/MIS, there was no difference in AOPP and AGE concentrations between these two groups of patients. Patients with recurrent mediator-related symptoms had lower AOPPs and AGEs as compared to patients without symptoms. AOPPs and AGEs were inversely correlated with the severity of symptoms, and in patients with symptoms, AOPPs correlated with tryptase levels.

DISCUSSION

Our data show that mastocytosis is associated with a state of increased oxidative stress that, in patients with mediator-related symptoms, correlates with mast cell burden as assessed by tryptase. Patients with symptoms presumably have an adaptive response resulting in lower blood levels of AOPPs and AGEs.

The Evaluation of Concentration - In-Vitro Release Relationship for Topical Semisolid Formulations of Sodium Cromoglycate

PURPOSE

The aim of the study was to evaluate the concentration - in-vitro release relationship for topical semisolid formulations of sodium cromoglycate. Materials / Methods. According to usual pharmaceutical compounding practice, commercially available cosmetic emulsions were used as vehicles for topical semisolid dosage forms containing 0.5, 2, 4 and 10% disodium cromoglycate (CS). The in-vitro release profiles and structural parameters of the resulting formulations was evaluated in a correlated manner, in order to reveal potential differences in the in-vivo performance.

RESULTS

Depending on the hydro-lipophilic characteristics of the vehicle and on the quantity of drug dissolved or dispersed, the structure and the release kinetics are distinct.

CONCLUSIONS

The results suggested that current lack of an unitary approach for the compounding of semisolid dosage forms of CS, resulting from the lack of widely available, standardized dosage form could be a reasonable explanation for the apparent discrepancy in the reports of clinical outcome after topical administration.

Long-lasting complete response to imatinib in a patient with systemic mastocytosis exhibiting wild type KIT

Systemic mastocytosis (SM) is a hematopoietic disorder characterized by abnormal expansion of mast cells (MCs) in visceral organs. The skin is involved in most cases. In adult patients the transforming KIT mutation D816V is usually present and confers resistance against imatinib. Therefore, imatinib is not recommended for patients with KIT D816V+ SM. Nonetheless, imatinib may work in patients with SM lacking KIT D816V. However, little is known about long-term efficacy and safety of this drug in SM. We report on a 62-year-old female patient with indolent SM (ISM) who suffered from severe debilitating skin involvement despite therapy with anti-mediator-type drugs, psoralen and ultraviolet-A-radiation. Although multifocal MC infiltrates were detected in the bone marrow by immunohistochemistry, no KIT mutation was found by sequencing analysis. In 2003, treatment with imatinib (induction, 400 mg/day; maintenance, 200 mg/day) was initiated. During therapy, skin lesions and tryptase levels decreased. Treatment was well tolerated without any side effects. After 10 years, skin lesions have disappeared and the tryptase level is within normal range. This case-study confirms the long-term efficacy and safety of imatinib in patients with SM lacking activating KIT mutations. Imatinib should be considered in select cases of SM in whom MCs exhibit wild-type KIT.

Bullous mastocytosis mimicking congenital epidermolysis bullosa

A 2-month-old female infant was referred to DebRA Mexico from the Regional Children's Hospital because of a generalized dermatosis from birth characterized by multiple blisters and erosions on the trunk, face and limbs, associated with minor trauma. A skin biopsy showing subepidermal blisters associated with a dermal infiltrate of Giemsa-positive cells and CD117-positive antibody was consistent with the diagnosis of bullous mastocytosis. Treatment with oral antihistamines, topical steroids, and antibiotics was initiated, leading to a remission of the lesions.

Spectrum of mast cell activation disorders

Mast cell (MC) activation disorders present with multiple symptoms including flushing, pruritus, hypotension, gastrointestinal complaints, irritability, headaches, concentration/memory loss and neuropsychiatric issues. These disorders are classified as: cutaneous and systemic mastocytosis with a c-kit mutation and clonal MC activation disorder, allergies, urticarias and inflammatory disorders and mast cell activation syndrome (MCAS), idiopathic urticaria and angioedema. MCs are activated by IgE, but also by cytokines, environmental, food, infectious, drug and stress triggers, leading to secretion of multiple mediators. The symptom profile and comorbidities associated with these disorders, such as chronic fatigue syndrome and fibromyalgia, are confusing. We propose the use of the term 'spectrum' and highlight the main symptoms, useful diagnostic tests and treatment approaches.

Severity of cutaneous findings predict the presence of systemic symptoms in pediatric maculopapular cutaneous mastocytosis

Although the prognosis of maculopapular cutaneous mastocytosis (MPCM), also referred to as urticaria pigmentosa, is often benign, clinicians lack evidence to reliably predict those at risk of associated systemic manifestations. We sought to elucidate clinical markers of disease severity to provide better treatment and prognostic information for individuals with MPCM. A retrospective chart review querying characteristics of children diagnosed with MPCM in the Emory Dermatology Clinic was performed. Follow-up was obtained through a clinical encounter or telephone interview. Linear regression was used to determine predictors of the number of MPCM-related systemic symptoms. Of 67 subjects, 57% were male, and the mean age of onset was 4.5 months. The maximum number of MPCM lesions was 1 to 10 in 16%, 11 to 30 in 33%, 31 to 50 in 25%, 51 to 100 in 6%, and more than 100 in 20% of subjects. For their MPCM lesions, 46% of subjects reported itching, 34% flushing, and 25% blistering. Reported systemic symptoms included diarrhea (22%), abdominal pain (15%), wheezing or dyspnea (13%), vomiting (10%), bone pain (10%), headaches (8%), cough (10%), rhinorrhea (8%), irritability (6%), and anaphylaxis (1.5%). In a multivariate linear regression analysis, the maximum number of MPCM lesions (p = 0.02) and the number of skin symptoms (p < 0.01) were statistically significant predictors of the number of systemic symptoms, controlling for age of onset, body sites involved, and sex. The correlation between cutaneous findings and symptomatology could aid clinicians in identifying individuals with MPCM who might warrant systemic evaluation and therapy.