Ahmed Yasser Nada

Introduction. Mastocytosis is a rare neoplasm characterized by abnormal proliferation and activation of clonal mast cells usually harbouring the KIT D816V mutation. Systemic symptoms of mastocytosis induced by mast cell mediators can occur spontaneously or are provoked by certain stimuli such as hymenoptera insect stings and blood-sucking dipteran insect bites. Today, the epidemiological aspects, features of clinical presentation and laboratory diagnosis associated with insect bites in children with cutaneous mastocytosis are poorly known.Aim. To review the incidence, clinical and laboratory features of insect allergy in children with various clinical forms of cutaneous mastocytosis.Materials and methods. A prospective observational single‐centre study was conducted. It contained information from 310 children who underwent outpatient treatment and observation at the State Budgetary Healthcare Institution – Moscow Center of Dermatovenereology and Cosmetology during the period from March 2022 to October 2024.Results. Reactions to Hymenoptera bites in the group of children with cutaneous mastocytosis developed rarely, in 1.3% of cases. The risk group included children with maculopapular cutaneous mastocytosis with a basal serum tryptase (BST) level above 5.0 μg/L. The proportion of children with systemic manifestations to bites of both stinging and blood-sucking insects and a BST level of more than 8.0 μg/L was 45.5%, which is significantly higher (p < 0.01) than the proportion of children with low BST values (18.1%). Reactions to Diptera (blood-sucking) insect bites were observed in 9.4% of children with all clinical forms of cutaneous mastocytosis. A study of the level of specific IgE to wasp venom showed an insignificant degree of sensitization in all children with systemic reactions to hymenoptera bites.Conclusions. Monitoring the dynamics of tryptase levels in children with cutaneous mastocytosis and timely therapeutic correction of cutaneous manifestations of mastocytosis (vesicles, wheals, itching, flushes) is an important aspect aspect of the prevention of systemic mediator symptoms and anaphylaxis to insect bites. Children with mastocytosis and insect allergy should be treated jointly by a dermatovenerologist and an allergist-immunologist. Particular attention should be paid to patients with monomorphic (“adult”) type of maculopapular cutaneous mastocytosis with tryptase level above 20.0 μg/l, who have risks of developing systemic mastocytosis and anaphylaxis to hymenoptera bites. The results of our study demonstrate the relevance of further study of clinical, epidemiological and laboratory features of insect allergy in a group of children with cutaneous mastocytosis.

Introduction. Mastocytosis is a heterogeneous group of diseases characterized by the abnormal accumulation of clonal mast cells (MCs) in various tissues and organs, including skin, bone marrow, liver, spleen and lymph nodes. The clinical picture of cutaneous and indolent systemic mastocytosis is formed by a wide range of symptoms associated with activation of mast cells. Single European studies have demonstrated wide variability in the frequency of gastrointestinal symptoms (GI-symptoms)) in children with mastocytosis (from 15 to 50%).Aim. To analyze the frequency of mediator-related GI-symptoms in children with different subtypes and clinical forms of mastocytosis.Materials and methods. A prospective observational study included data from 289 children aged 3 to 17 years who were under observation at the Moscow Scientific and Practical Center of Dermatovenereology and Cosmetology. Symptoms were assessed using the Pediatric grade scale of symptoms of mastocytosis. Clinical manifestations of reactions caused by mast cell degranulation were compared with data from clinical and laboratory studies. The concentrations of tryptase and histamine in the blood serum of patients were determined. The incidence of organomegaly and mesenteric lymphadenitis in children with mediating symptoms and without symptoms was determined using ultrasound.Results. 67 (23.2%) patients had GI symptoms. More than half of the patients (51.6%) indicated abdominal pain, 32.3% reported diarrhea. The severity of pain symptoms correlated with the level of serum tryptase (_ρ = 0.564, p < 0.01). The incidence of hepatomegaly and mesadenitis in children with GI- symptoms was 19.4% and 25.4%, respectively. In a comparative analysis in groups of children with and without GI symptoms, the differences in the number of identified cases of organomegaly and mesadenitis were statistically significant (p < 0.001). An increase in histamine levels in the blood was detected in half of the patients with complaints of heartburn and nausea.Conclusion. Our results demonstrated that a study of the level of serum tryptase, ultrasound of the abdominal organs and lymph nodes should be carried out in all children with mediator-related GI-symptoms regardless of the clinical form of mastocytosis.

Relevance.Amonomorphic type of maculo-­papular cutaneous mastocytosis was allocated relatively recently. Inchildren and adolescents with amonomorphic type of MPCM (adult type pattern), clinical manifestations persist into adulthood and can transform into asystemic process, which determines the need for regular monitoring of this category of patients.Theaimwas to analyse the results of clinical, laboratory and instrumental examinations of an adolescent with amonomorphic type of MPCM.Materials and Methods. The study of an adolescent patient included data of laboratory examination, pathomorphological examination, ultrasound examination of the abdominal organs and cKIT gene of an adolescent with amonomorphic type of MPCM, observed at “Moscow Scientific and Practical Center of Dermatovenerology and Cosmetology”.Resultsand Discussion.The process was represented by multiple rashes on the skin of the trunk and limbs. Darier’s sign is positive. The patient’s serum tryptase level exceeded the age norm. The late onset (atthe age of 12)of the disease, elevated tryptase levels, neurological symptoms, and the risk of anaphylaxis caused alertness regarding the development of the systemic form, therefore an ultrasound examination of the abdominal organs was performed and the presence of amutation in the cKIT gene in peripheral blood was determined.Conclusion.Clinical report of an adolescent patient in Moscow Scientific and Practical Center of Dermatovenerology and Cosmetology was presented. Thus, the combination of clinical and laboratory data allows minimizing the number of invasive procedures in children with CM. Assessment of the tryptase level, mutation detection in the cKIT gene and ultrasound examination of abdominal organs can be useful for timely diagnosis of systemic mastocytosis, which allows to carry out the necessary correction of the disease status and drug therapy.

Introduction. Flushing is a subjective feeling of warmth that is accompanied by redness of the skin on any part of the body, but mainly on the face, neck and upper trunk. Episodic flushing with other symptoms associated with mast cell mediators can be observed in 30–50% of children with cutaneous mastocytosis (CM).Aim. To analyze the frequency of flushing in children with various clinical forms of cutaneous mastocytosis. To study serum tryptase levels in children with flushing.Materials and methods. The study included data from 275 children aged from 6 months to 17 years inclusive, who were undergoing outpatient treatment and observation at the Moscow Scientific and Practical Center of Dermatovenereology and Cosmetology from March 2022 until January 2024. The concentration of tryptase in the blood was determined by immunofluo-rescence on a three-dimensional porous solid phase (ImmunoCAP technology, Pharmacia Diagnostics AB, Sweden). Polarization and immersion dermatoscopy with 20x magnification were performed.Results. Flushings were observed in 17.5% of patients out of 275 observed children with CM. The level of tryptase more than 15 µg/l was determined in 20.8% of children with flushing, above 11.0 µg/l – in 37.5%. Tryptase levels were higher than 8.0 µg/L in 22 (45.8%) patients. In 25.0% of patients with flushing, tryptase levels did not exceed 5 µg/L. The severity of the vascular pattern in lesions and apparently healthy skin was characteristic of patients with frequent or prolonged flushing and tryptase levels above 8.0 µg/L.Conclusion. This study was the first in the Russian Federation to demonstrate the prevalence of flushing in children with various clinical forms of cutaneous mastocytosis. The results showed that the assessment of serum tryptase levels should be performed in all children with flushing, regardless of the clinical form of mastocytosis, including those with isolated and multiple skin mastocytomas. Clinical laboratory and dermatoscopic monitoring are important for the development of individual therapeutic tactics and prevention of mediator reactions and anaphylaxis.