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.

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.

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.

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.

Paediatric mastocytosis: long-term follow-up of 53 patients with whole sequencing of KIT. A prospective study.

BACKGROUND: Mastocytosis is a heterogeneous group of clinical disorders characterized by the abnormal accumulation of mast cells. The adult and paediatric forms differ in their clinical and genetic features and outcomes. OBJECTIVES: To describe the clinical evolution of a well-characterized cohort of paediatric mastocytosis (PM), and to analyse the relationship between KIT mutation and the clinical course. METHODS: This was a prospective cohort study performed at the National Clinical Reference Center for Mastocytosis. Diagnosis was confirmed by identification of KIT mutation on lesional skin biopsy. Mastocytosis subtype, mast cell mediator-related symptoms (MC MRS) and clinical course were recorded. Fifty-three patients with PM and > 4 years of disease course were enrolled. The mean ± SD age at the final evaluation was 13·2 ± 4·8 years. The main outcome was the type of KIT mutation as a predictor of evolution and clinical characteristics. RESULTS: Patients presented with maculopapular cutaneous mastocytosis (n = 44), diffuse cutaneous mastocytosis (n = 6) or mastocytoma (n = 3). The mean duration of disease was 12·1 years. Substantial or partial cutaneous regression (18 of 53 and 16 of 53), stabilization or aggravation (16 of 53) and complete cutaneous regression (three of 53) were noted. MC MRS mainly regressed (21 of 53). For 22 patients, evolution of MC MRS and evolution of cutaneous lesions were different. No significant association between evolution and KIT mutation or between evolution and type of cutaneous mastocytosis was found. A late onset of the disease (after 2 years) is associated with worse evolution. CONCLUSIONS: PM is not systematically self-regressive. MC MRS manifestations and cutaneous lesions can persist or increase overtime. KIT mutation is not a predictor of evolution.

Atypical maculopapular cutaneous mastocytosis showing a nevus spilus-like lesion.

A 13-year-old Korean girl presented with a 7-year history of a pruritic, light-brown patch containing multiple 0.2- to 0.5-cm brownish-to-reddish maculopapules on the left anterior chest. When her skin was rubbed, the lesion became itchy and red. Histopathologic evaluation demonstrated marked dense dermal infiltration of mast cells. We report a rare case of atypical maculopapular cutaneous mastocytosis with clinical features similar to those of nevus spilus.

Longitudinal Study of Pediatric Urticaria Pigmentosa.

BACKGROUND/OBJECTIVES: Urticaria pigmentosa (UP) is the most common form of mastocytosis in children and is associated with systemic signs, symptoms, and triggers. To our knowledge, the effect of UP on children's quality of life has not been studied. The objective of the current study was to characterize the natural history, triggers, and complications of pediatric UP, identify prognostic indicators, and determine its effect on quality of life. METHODS: Between 2002 and 2007, children with three or more mastocytomas diagnosed by a pediatric dermatologist were recruited during visits at the Children's Hospital of Wisconsin Dermatology Clinic (Milwaukee, WI). Research visits were conducted every 3 years and telephone interviews yearly. The Children's Dermatology Life Quality Index was administered to subjects 4 years of age and older at enrollment. Laboratory test results were collected for subjects younger than 4 years at enrollment. Subjects were followed until UP resolution or study end in August 2015. RESULTS: The final cohort size was 43 subjects followed for a median of 8.1 years. Twenty-six subjects were followed through study completion. At age 12 years, 6 patients had disease resolution and 14 remained active. Patients who had disease resolution before age 12 years were more likely to be male and had fewer years of age and smaller lesions, fewer affected areas, and earlier onset. Common medications and anesthetics resulted in no serious reactions. Hymenoptera stings occurred in 51%, with no reports of anaphylaxis. No patient reported a severe effect on quality of life, with most indicating mild to no effect. CONCLUSION: Severe complications are not common with historically identified triggers. Disease does not resolve before adolescence in most children. UP has a minimal effect on quality of life for most children.

Telangiectasia macularis eruptiva perstans: an old terminology, still frequently used.

The term telangiectasia macularis eruptiva perstans (TMEP) was originally used to describe a rare form of cutaneous mastocytosis (CM) that was limited to the skin with lesions consisting of irregular, telangiectatic macules ranging in color from red to brown. Recent guidelines, however, recommended that the sole presence of telangiectasias should not form the basis of a distinct variant of CM. We conducted a review of the literature from 1930 to 2017 and found 76 cases that were reported as TMEP. Owing to a general misconception about diagnosis of CM and SM, there is a need for further discussion and awareness of the newly proposed World Health Organization (WHO) guidelines.

Large maculopapular cutaneous lesions are associated with favorable outcome in childhood-onset mastocytosis.

BACKGROUND: Mastocytosis, characterized by pathologic accumulation of mast cells, can manifest itself in adulthood or childhood. Pediatric patients usually have cutaneous mastocytosis (CM) with mast cell infiltrates limited to the skin and spontaneous improvement of skin lesions after several years. However, there are some patients with persistent disease resembling adulthood-onset mastocytosis. OBJECTIVE: The current classification of CM differentiates between 3 subforms. In clinical practice we noticed that different variants of these subforms might exist, particularly in patients with childhood-onset mastocytosis. Therefore, in the present study, we aimed to investigate whether specific cutaneous lesions in patients with childhood-onset mastocytosis are associated with other disease parameters. METHODS: We analyzed 144 patients with a disease onset of less than age 17 years using a systematic dermatologic approach. RESULTS: One hundred twenty-two patients presented with maculopapular cutaneous mastocytosis (MPCM), 12 patients presented with diffuse CM, and 10 patients presented with solitary mastocytoma of the skin. Patients with MPCM showed particularly heterogeneous cutaneous lesions and were therefore grouped into 3 variants presenting either with small lesions (MPCM-small, skin lesions <1 cm in diameter; n = 19), large lesions (MPCM-large, skin lesions ≥ 1 cm in diameter; n = 89), or atypical lesions (MPCM-other, n = 14). Patients with MPCM-large lesions, compared with those with MPCM-small lesions, were characterized by significantly lower tryptase levels, shorter disease duration, and earlier disease onset. In addition, more patients with MPCM-large lesions exhibited spontaneous regression of cutaneous lesions. CONCLUSION: Our data show that patients with MPCM-large lesions compared with those with MPCM-small lesions have a more favorable disease course and suggest exploring the size of cutaneous lesions as a prognostic parameter in childhood-onset MPCM.

[Cutaneous mastocytosis: A case report]. / Mastocitosis cutánea: reporte de un caso.

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.

Novel R634W c-kit mutation identified in familial mastocytosis.

Familial mastocytosis is a well-documented but rare entity, with fewer than 100 cases reported in the literature. The etiology has most commonly been linked to activating c-kit mutations, with several mutations reported to date. We present a novel familial mastocytosis-associated c-kit mutation (R634W) in three siblings with urticaria pigmentosa. This mutation has been previously described in mucosal melanoma, chronic myelomonocytic leukemia, and acute myeloid leukemia. Because this is a rare mutation, it is unclear whether screening for other disease states associated with the mutation would be of benefit.

Urticaria pigmentosa-like disease in a dog.

Urticaria pigmentosa is a rare dermatologic syndrome in humans, cats, and dogs. This report documents a case of canine urticaria pigmentosa-like disease with unusual features and no C-kit mutation.

Maladie s'apparentant à l'urticaire pigmentaire chez un chien. L'urticaire pigmentaire est un syndrome dermatologique rare chez les humains, les chats et les chiens. Ce rapport documente un cas canin s'apparentant à l'urticaire pigmentaire comportant des caractéristiques inhabituelles et l'absence de mutation C-kit.(Traduit par Isabelle Vallières).

Disseminated brown macules in an infant.

Urticaria pigmentosa is the most common form of mastocytosis. Mastocytosis usually presents at birth or early childhood, and may involve only the skin or, less commonly, other internal organs. Diagnosis is clinical, but a skin biopsy may be useful. Prognosis is usually good, and treatment focuses on the avoidance of certain triggers and administration of topical and systemic medications. Appropriate counselling of parents regarding the benign nature of this disease is important as most cases resolve by adolescence.

Cutaneous mastocytosis: a case of bullous urticaria pigmentosa.

Mastocytosis is characterized by an increased number of mast cells with abnormal growth and accumulation in 1 or more organs. In children, mastocytosis is commonly cutaneous and patients present with a spectrum of findings, ranging from solitary or multiple mastocytomas to urticaria pigmentosa (UP) or diffuse cutaneous mastocytosis (CM). We present a case of a 4-month-old infant with bullous UP.