Urticaria Pigmentosa Without Pruritus.

Mastocytosis is a group of disorders characterized by the pathologic accumulation of mast cells in various tissues. One example of mastocytosis is urticaria pigmentosa, which presents with mastocytomas that can cause hives and, when irritated, pruritus. To our knowledge, we are describing the first case of urticaria pigmentosa without pruritus. The patient had a positive Darier's sign, stated that they never felt itchy, and denied ever using a topical steroid or antihistamine. Although our patient declined additional testing, patients like this may benefit from a detailed evaluation of their sensory system through both quantitative sensory testing and genetic analysis. J Drugs Dermatol. 2024;23(3):     doi:10.36849/JDD.7558e.

[MACULOPAPULAR CUTANEOUS MASTOCYTOSIS HARBORING A KIT MUTATION (ASP419DEL): A CASE REPORT].

A 2-year-old, male patient presented with an 18-month history of scattered, brown macules and nodules up to 2 cm in size on his trunk and extremities. These macules were accompanied by pruritus and were positive for Darier's sign. A skin biopsy of a brown macule on the left thigh revealed a dense accumulation of CD117-positive, round or oval cells with amphophilic cytoplasm within the upper to middle dermis. The patient was otherwise healthy and had normal laboratory and imaging test results. Sequence analysis of genomic DNA from a skin biopsy demonstrated the presence of an Asp419del mutation in exon 8 of the KIT gene. Based on these findings, maculopapular cutaneous mastocytosis (MPCM) was diagnosed. The patient received H 1-antihistamine. Although the pruritus resolved, the brown macules remained for one year after the initial treatment. To the best of our knowledge, only three cases of cutaneous mastocytosis (CM) with an Asp419del mutation, including the present case, have been reported in the Japanese literature to date; moreover, while the previous two cases were of DCM, the present case was the first instance of MPCM. Normally, the symptoms of childhood-onset MPCM are dormant until puberty. However, a recent study reported that many MPCM patients may experience persistent or exacerbated symptoms. The present study therefore evaluated 53 Japanese cases of childhood onset MPCM with a KIT gene mutation and discussed the patients' clinical outcomes.

[Mastocytosis in children]. / Mastozytose bei Kindern.

Mastocytosis in children is a rare disease characterized by an abnormal accumulation of tissue mast cells. Mastocytosis in children presents with typical skin alterations that are classified as maculopapular cutaneous mastocytosis, diffuse cutaneous mastocytosis, or mastocytoma. Some patients also develop mast cell mediator symptoms, such as pruritus, flush, and anaphylaxis. In many children, the disease is characterized by a benign and usually self-limiting course; systemic mastocytosis with extracutaneous involvement and a chronic or progressive course is found only rarely. Therapeutically, H1 antihistamines are primarily used on an as-needed basis or as continuous treatment, depending on the severity. Children, parents and caregivers should be thoroughly educated about the clinical picture and possible trigger factors of mast cell mediator release. For children with extensive skin alterations and severe symptoms, the prescription of an epinephrine auto-injector is recommended for emergency treatment.

Mastocytosis in children: a single-center long-term follow-up study.

BACKGROUND: Mastocytosis is a heterogeneous group of rare disorders characterized by the accumulation of clonal mast cells in organs such as the skin and bone marrow. The diagnosis of cutaneous mastocytosis (CM) is based on clinical findings, positive Darier's sign, and histopathology, if necessary. METHODS: Medical records of 86 children with CM diagnosed during a 35-year long period were reviewed. Most patients (93%) developed CM during the first year of life (median age 3 months). Clinical features at presentation and during the follow-up period were analyzed. Baseline serum tryptase level was measured in 28 patients. RESULTS: A total of 85% of patients had maculopapular cutaneous mastocytosis/urticaria pigmentosa (MPCM/UP), 9% had mastocytoma, and 6% had diffuse cutaneous mastocytosis (DCM). Boy to girl ratio was 1.1:1. Fifty-four of 86 patients (63%) were followed from 2 to 37 years (median 13 years). Complete resolution was registered in 14% of mastocytoma cases, 14% of MCPM/UP, and in 25% of DCM patients. After the age of 18, skin lesion persisted in 14% mastocytoma, 7% MCPM/UP, and 25% children with DCM. Atopic dermatitis was diagnosed in 9.6% of patients with MPCM/UP. Three of 28 patients had elevated serum tryptase. Prognosis in all patients was good, and there were no signs of progression to systemic mastocytosis (SM). CONCLUSION: To the best of our knowledge, our results represent the longest single-center follow-up study of childhood-onset CM. We found no complications of massive mast cell degranulation or progression to SM.

Histopathological characteristics are instrumental to distinguish monomorphic from polymorphic maculopapular cutaneous mastocytosis in children.

BACKGROUND: Mastocytosis is characterized by the accumulation of mast cells (MCs) in the skin or other organs, and can manifest at any age. A significant number of paediatric mastocytosis cases persist after puberty. In particular, monomorphic maculopapular cutaneous mastocytosis (mMPCM) is often persistent and associated with systemic mastocytosis. However, clinical differentiation of MPCM from polymorphic (p)MPCM can be difficult. AIM: To identify histopathological features that can help to distinguish mMPCM from other subtypes of paediatric mastocytosis. METHODS: This was a retrospective study using skin biopsies from patients with any subtype of mastocytosis. The localization and density of the MC infiltrate, MC morphology and expression of aberrant markers were evaluated and correlated with clinical characteristics. RESULTS: In total, 33 biopsies were available for evaluation from 26 children [(10 with mMPCM, 5 with mastocytoma, 3 with diffuse cutaneous mastocytosis (DCM), 8 with pMPCM)] and 7 adults with MPCM. The MC number was increased in all patients, but was higher in children than adults (P < 0.01). The presence of mMPCM was associated with sparing of the papillary dermis from MC infiltration, whereas MC density in the papillary dermis was highest in pMPCM and DCM (P < 0.01). The positive predictive value of the presence of a reticular MC infiltrate for mMPCM was 72.7% (95% CI 51.4-87.0), and the negative predictive value was 83.3% (95% CI 42.2-97.2). There were no relevant differences in the expression of CD2, CD25 or CD30 between the different subtypes. CONCLUSION: Skin histopathology might enhance the phenotypical differentiation of mMPCM from other subtypes in children, thereby increasing the accuracy of one's prognosis.

Cutaneous mastocytosis in a child with a de novo GNB1 mutation.

In the last few years, de novo mutations in the GNB1 gene have been found to cause a neurodevelopmental disorder typically characterized by global developmental delay and hypotonia. Only 4 cases of maculopapular cutaneous mastocytosis in children with GNB1 mutations have been reported to date. Here, we describe another case of the condition with concomitant cutaneous mastocytosis.

Clinical and Demographic Characteristics of Cutaneous Mastocytosis in Childhood: Single-center Experience.

INTRODUCTION: Mastocytosis is a rare and heterogenous disease, and in children it is generally limited to the skin and tends to regress spontaneously in adolescence. AIM: In this study, demographic, clinical, and laboratory characteristics of pediatric patients with mastocytosis, and also coexisting diseases were investigated. RESULTS: A total of 61 pediatric patients were included in the study. The male-to-female ratio was 2.2, the median age was 2 years (range, 0.25 to 19 y), and the median follow-up period was 2.0 years (range, 0.25 to 19 y). Types of clinical presentation at diagnosis consisted of mainly urticaria pigmentosa (45.9%). Seven patients were further investigated with suspicion of systemic mastocytosis, they were followed up, median of 9 years (range, 2.5 to 16 y), and none of them developed systemic disease. Coexisting allergic diseases were recorded in total 5 patients (8.2%). Three patients had immunoglobulin A deficiency, 1 patient had elevated immunoglobulin E level. A patient developed mature B-cell lymphoma with a heterozygous mutation in c-KIT exon 11. DISCUSSION: Cutaneous mastocytosis in children may present as a complex disease with different clinical signs and symptoms. Standardized clinical criteria and guidelines for the follow-up of children with mastocytosis are required.

Maculopapular Cutaneous Mastocytosis Successfully Treated with Omalizumab.

Dear Editor, Maculopapular cutaneous mastocytosis (MPCM), formerly telangiectasia macularis eruptiva perstans (TMEP), is an uncommon form of cutaneous mastocytosis first described on 1930 (1). It is more frequent in adults, and early diagnosis is crucial since it has been reported to be associated with serious underlying systemic disorders, such as myeloproliferative diseases and severe manifestations like anaphylaxis (2,3). Treatment of MPCM depends on the presence of systemic involvement and/or the clinical symptoms of the disease itself. A 52-year-old woman was referred to us with pruritic brown red telangiectatic macules located on her arms, chest, and back (Figure 1, a, b, c) that had appeared over a period of 5 years. The patient also reported photosensitivity and facial flushing. Physical examination revealed a positive Darier sign (Figure 1, d) without other clinical signs suggestive of systemic involvement (e.g. lymphadenopathy, hepatosplenomegaly, malabsorption syndrome). Skin biopsy demonstrated abundant mast cells infiltration with granulomatic metachromasia (Giemsa stain; Figure 2, a) while immunohistochemistry demonstrated mast cells positivity in CD117/c-KIT (Figure 2, b). A detailed laboratory investigation was carried out, including complete blood count (IgE:1800 IU/mL), peripheral blood film examination, bone marrow biopsy, liver function tests, and serum tryptase levels (7 ng/mL). All performed tests were normal, thus excluding systemic disease. H1 receptor antagonists are considered the first-choice therapeutic option for control of symptoms among patients with skin mastocytosis (4,5). In our case, despite the standard application of an increased dose of different H1-receptor antagonists combined with topical steroid preparations, the patient showed no response to treatment and suffered a significant adverse influence on her quality of life and daily activities. Recent studies in single cases or small case-series have shown promising results for omalizumab in mastocytosis (6-8). Accordingly, our patient was switched to omalizumab 300 mg every 4 weeks for a one-year period. Both pruritus and flushing significantly improved after 2 months of treatment with only anti-IgE, and fully resolved during the fifth month of treatment. Almost 18 months, later the patient remains fully controlled with apparent significant improvement of her quality of life. The mechanisms of action for omalizumab in patients with mastocytosis are not well known. Omalizumab inhibits binding of IgE to the surface of mast cells and basophils by forming complexes with free IgE in serum, and this represents a possible explanation of the reduction of mast cell and basophil activation (9). In the future, omalizumab may be considered as a good alternative therapeutic option in cases where antihistamines have failed, though more research is necessary.

Case Report and Review of the Literature: Bullous Skin Eruption After the Booster-Dose of Influenza Vaccine in a Pediatric Patient With Polymorphic Maculopapular Cutaneous Mastocytosis.

Vaccination is a well-known trigger for mast cell degranulation in subjects affected by mastocytosis. Nevertheless, there is no exact standardized protocol to prevent a possible reaction after a vaccine injection, especially for patients who have already presented a previous vaccine-related adverse event, considering that these patients frequently tolerate future vaccine doses. For this reason, we aim to share our experience at Meyer Children's University Hospital in Florence to raise awareness on the potential risk for future vaccinations and to discuss the valuable therapeutic strategies intended to prevent them, taking into account what is proposed by experts in literature. We describe the case of an 18-month-old female affected by a polymorphic variant of maculopapular cutaneous mastocytosis that presented an extensive bullous cutaneous reaction 24 hours after the second dose (booster dose) of inactivated-tetravalent influenza vaccine, treated with a single dose of oral corticosteroid therapy with betamethasone (0.1 mg/kg) and an oral antihistamine therapy with oxatomide (1 mg/kg/daily) for a week, until resolution. To the best of our knowledge, in the literature, no documented case of reaction to influenza vaccine in maculopapular cutaneous mastocytosis is described. Subsequently, the patient started a background therapy with ketotifen daily (0.05 mg/kg twice daily), a non-competitive H1-antihistamine, and a mast cell stabilizer (dual activity). A non-standardized pharmacological premedication protocol with an H1-receptor antagonist (oxatomide, 0.5 mg/kg) administered 12 hours before the immunizations, and a single dose of betamethasone (0.05 mg/kg) together with another dose of oxatomide (0.5 mg/kg) administered 2 hours before the injections was followed to make it possible for the patient to continue with the scheduled vaccinations. Indeed, no reactions were subsequently reported. Thus, in our experience, a background therapy with ketotifen associated with a premedication protocol made by two doses of oxatomide and a single dose of betamethasone was helpful to make possible the execution of the other vaccines. We suggest how in these children, it could be considered the idea of taking precaution when vaccination is planned, regardless of the kind of vaccine and if a dose of the same vaccine was previously received. However, international consensus needs to be reached to manage vaccinations in children with mastocytosis and previous adverse reactions to vaccines.

Interobserver variability in the classification of childhood maculopapular cutaneous mastocytosis.

BACKGROUND: Maculopapular cutaneous mastocytosis (MPCM) in children is classified in two variants: (i) monomorphic variant, presenting with the small macules or papules typically seen in adult patients; and (ii) polymorphic variant with larger lesions of variable size and shape, typically seen in children. The definition of polymorphic and monomorphic variants is mostly intuitive, and a validation of this classification has not been done. OBJECTIVE: To study interobserver variability in the classification of MPCM in two groups of observers: mastocytosis experts and general dermatologists. MATERIALS AND METHODS: Nineteen cases of childhood MPCM were shown blindly, for classification as monomorphic or polymorphic type, to 10 independent observers (eight dermatologists, one allergist and one haematologist) from Europe and North America with a vast experience in the management of paediatric mastocytosis. Also, the same cases were shown on a screen to 129 general dermatologists attending a meeting; their votes were registered by remote controls. The interobserver variability kappa coefficient (with 95% confidence interval) was calculated to measure the reliability of the correlation. RESULTS: The value of kappa interobserver variability coefficient for the group of 10 experts (95% confidence interval) was 0.39 (0.18-0.63), which is considered as 'fair'. The value of kappa interobserver variability coefficient for the group of 129 general dermatologists (95% confidence interval) was 0.17 (0.06-0.39), which is considered as 'slight'. A complete agreement of all 10 experts was achieved in only four of 19 cases (21.1%) The most voted choice was concordant between the two groups in only 11 of the 19 cases. CONCLUSIONS: We failed to validate the classification system of childhood MPCM in monomorphic and polymorphic types. While the rate of agreement was low for mastocytosis experts, it was nearly the agreement expected by chance in general dermatologists.

Cutaneous Mastocytosis in a Pediatric Dental Patient: Multidisciplinary Approach to Oral Management.

Mastocytosis is a heterogeneous disease of bone marrow origin, characterized by local or diffuse increased growth and accumulation of clonal mast cells in the skin and/or in internal organs. The skin is the organ most frequently involved, but others may be affected as well. The purpose of this article is to present the oral management of a child with urticaria pigmentosa/maculopapulous cutaneous mastocytosis requiring dental treatment under general anesthesia. The multidisciplinary team approach involving the relevant medical specialists is discussed to emphasize the significance of coordinated patient management.

Prevalence of atopic diseases in children with papular urticaria

BACKGROUND: Papular urticaria is a hypersensitivity reaction characterized by chronic and recurrent papular erythema. It occurs as a result of the bites of mosquitoes, fleas, bed bugs, and other insects; and it is generally seen in children. This study examines the prevalence of atopic diseases in patients with papular urticaria. METHODS: The medical records of 130 pediatric patients with the diagnosis of papular urticaria between August 2017 and August 2019, whose disease progression was followed in two ter­tiary care centers, were reviewed retrospectively. The patients were divided into two groups: under 5 and above 5 years old. The prevalence of the atopic disease in children with papular urticaria was compared with those in age-matched controls without papular urticaria. RESULTS: The study included 130 patients who were diagnosed with papular urticaria (64 males, 66 females, median age: 60 months). The prevalences of atopic disease, recurrent wheezing, and atopic dermatitis were higher in the group under 5 years old with papular urticaria than in the same-age control group (p = 0.001, 0.002, and 0.001, respectively). The prevalences of atopic disease, asthma, allergic rhinitis, and atopic dermatitis were higher in the group above 5 years old with papular urticaria than in the same-age control group (p = 0.001, 0.001, 0.001, and 0.007, respectively). CONCLUSIONS: Many children with papular urticaria are atopic children. These patients should be assessed not only in terms of papular urticaria but also in terms of comorbid atopic diseases

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Assessing vaccination reactions in pediatric patients with maculopapular cutaneous mastocytosis.

Immunization compliance in the United States is declining, in part due to misinformation and fear surrounding adverse vaccination reactions. Recently, there have been data published in the allergy and immunology literature to show that there may be a relationship between routine vaccinations and induction of symptoms in cutaneous mastocytosis patients; however, this has not yet been explored in the dermatology literature. We sought to uncover the prevalence of vaccine reactions due to mast cell activation within our cohort of maculopapular cutaneous mastocytosis (MPCM) patients in order to contribute to ensuring administration safety, managing familial expectations, and encouraging continued adherence. Our results indicate that while incidence of reaction rates may be higher than the national average, they are mild and families should be counseled to follow recommended immunization schedule guidelines.

Pediatric maculopapular cutaneous mastocytosis: Retrospective review of signs, symptoms, and associated conditions.

BACKGROUND/OBJECTIVES: Though maculopapular cutaneous mastocytosis is the most common form of pediatric mastocytosis, it remains unclear which patients will experience severe symptoms. We sought to better define the presentation and the cutaneous and systemic signs and symptoms in patients with maculopapular cutaneous mastocytosis. METHODS: We analyzed retrospective data on 227 patients diagnosed with maculopapular cutaneous mastocytosis prior to age 15 years from five US clinical sites. We collected data on signs, symptoms, age of onset, and laboratory testing. RESULTS: Median age of onset of maculopapular cutaneous mastocytosis was 3 months, with 94% of patients presenting prior to age 2 (range 0-15 years). Patients presenting before age 2 had significantly lower serum tryptase level (P = .019). Greater number of skin lesions (P = .006), number of reported skin signs and symptoms (P < .001), and higher tryptase levels (P < .001) were associated with more systemic symptoms. CONCLUSION: Children with maculopapular cutaneous mastocytosis, who have greater skin involvement, higher serum tryptase level, and more skin signs and symptoms, are more likely to have systemic symptoms.

A New Digital Method for Counting Mast Cells in Cutaneous Specific Lesions of Mastocytosis: A Series of Adult Cases of Mastocytosis With Clinical-Pathological Correlations.

ABSTRACT: Cutaneous mastocytosis is characterized by the abnormal accumulation of mast cells in the skin. However, mast cell counting is not always easy and reproducible with classical methods. This work aims to demonstrate the reliability, usability, and virtues of a new software used on digital tablets for counting mast cells in cutaneous specific lesions of mastocytosis, to assess differences in mast cell counts between clinical subtypes of mastocytosis in the skin, and to consider the feasibility of applying a diagnostic mast cell count cutoff to urticaria pigmentosa, which is the most frequent form of cutaneous mastocytosis. Using a new digital tablet software that was accessible by multiple observers through its own wireless network and allowed high resolution of the image without data compression, we counted the number of mast cells on slides of patients and control skins immunostained for CD117. We found that our counting method was highly reproducible and that the new software allowed very quick counting. We evidenced strong differences in the mast cell count between most of the clinical subtypes of mastocytosis in the skin. However, when applied to a subset of patients with urticaria pigmentosa, a diagnostic cutoff in the mast cell count lacked sensitivity. Thus, our digital method for counting CD117-immunostained mast cells was highly accurate and was of a significant value for the diagnosis of mastocytosis in the skin. However, some subtypes with low mast cell counts will still require the application of additional diagnostic criteria.

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.