Atopic dermatitis (AD) is a chronic inflammatory skin disease with high risk of skin and systemic infections. Preventive AD therapy is based on skin barrier improvement and anti-inflammatory treatment, whereas, severe skin and systemic infections require systemic therapy. This review describes pathophysiology and possible treatment and prevention methods for AD infectious complications.

Atopic dermatitis (AD) is a chronic inflammatory skin disease. Its crucial component of pathogenesis is malfunction of the epidermal barrier. Filaggrin protein and associated mutations in the filaggrin gene play one of the key roles in this problem. Nowadays new topical products (emollients) has been created and implemented into practice with the aim of more personalized approach and increased therapy efficacy in patients with AD. Such drugs would allow us to restore epidermal barrier function and to achieve elimination of disease symptoms.

The skin is the largest organ of the human body, it creates protective barrier between the internal and external environment. Skin barrier damage may result in homeostasis imbalance, inflammation, or bacterial infection. The microbiome plays a crucial role in maintaining normal skin functioning: control of pathogenic diversity of microorganisms, stimulate immune cells, and modulate chronic dermatoses development. There are various mechanisms for restoring skin barrier function. They are associated with the microorganisms’ activity. Thus, skin restoration is an important task included in the general concept of atopic dermatitis management. One of such methods is the skin surface colonization with commensals, so significant role is assigned to the new dermatological drugs. The normalization of the microbiome in affected skin areas with cosmetic care products can significantly affect the result of skin barrier restoration.

Acne is chronic inflammatory skin disease. Its examination and management tactics depend on the patient's age and disease clinical form. This article presents treatment algorithms for acne vulgaris in adolescent and pre-adolescent children and describes clinical cases.

Background. Excessive colonization of the skin by various bacteria and fungi can be noted in patients with atopic dermatitis (AD), and the prevalence of secondary infection complications 30–48%. Several studies have shown that Staphylococcus aureus colonization is 60–100% in patients with AD compared to 5–30% in healthy persons from the control group. Moreover, the incidence of methicillinresistant Staphylococcus aureus (MRSA) isolates is up to 10–30% in skin cultures at AD, according to experts. Therapy of AD complicated by secondary infection is one of the crucial challenges of modern dermatology. Mupirocin can be considered as one of the most effective topical antibiotic among others used for etiotropic therapy of infectious complications in AD patients, and it has been confirmed by numerous clinical studies.

Conclusion. Staphylococcus aureus is the most common trigger of AD aggravation. MRSA in AD complicated by secondary infection is difficult to manage as it becomes resistant to many types of antibiotics; however, it shows persistent sensitivity to mupirocin. Mupirocin-based (2%) external agent is the most effective, safe, and preferred therapy variant for AD complicated by secondary infection in pediatrics.

Background. Psoriasis is an independent risk factor for cardiovascular diseases (CVD). One of the markers associated with the CVD course is epicardial fatty tissue (EFT) that is thicker in psoriasis patients. EFT assessment can be used as a useful indicator of CVD in psoriasis patients. The data about the effect of genetically engineered biological therapy (GEBT), used for psoriasis management, on the EFT thickness is limited. Examination of GEBT effects on EFT may improve our understanding of CVD prevention in psoriasis patients.

Objective. The aim of the study is to study the changes in EFT thickness on GEBT.

Methods. A prospective cohort study included 56 children with severe and moderate psoriasis. Patients underwent transthoracic two-dimensional echocardiography (M-mode) with EFT thickness assessment and PASI (Psoriasis Area and Severity Index) scoring before the GEBT initiation. All the parameters were re-evaluated after 16 weeks. All patients were divided into three groups according to the initiated therapy: adalimumab, secukinumab and ustekinumab. When dividing the therapy received into groups, the age of the patients was taken into account: inclusion in the adalimumab group was carried out from 4 years, in the secukinumab and ustekinumab groups — from 6 years. Otherwise, the process of group assignment was random. The study results were processed using descriptive statistics methods: the changes in EFT thickness in individual groups were compared via the Wilcoxon test, and results were considered statistically significant at p 0.05.

Results. Before the start of therapy, in 56 patients the mean of EFT thickness was 2.11 mm, the mean PASI — 18.32. The adalimumab group had the following indicators: the mean EFT thickness before the therapy was 2.1 mm, and it has decreased to 1.77 mm after 16 weeks of therapy. The mean change in EFT thickness was 0.33 mm, and the median — 0.17 mm [CI 0.33 ± 0.25]. The ustekinumab group: the mean EFT thickness before the therapy was 2.13 mm, 16 weeks after — 1.69 mm. The mean change in EFT thickness was 0.44 mm, and the median — 0.38 [CI 0.44 ± 0.13]. The secukinumab group: the mean EFT thickness before the therapy was 2.08 mm, 16 weeks after — 1.82 mm. The mean change in EFT thickness was 0.27 mm, and the median — 0.27 [CI 0.27 ± 0.07]. Evaluation of indicators via Wilcoxon test has shown statistically significant decrease in the EFT after therapy in all groups (p 0.05). 73% of patients achieved PASI 50, and 6% — PASI 75 in the adalimumab group. 21% of patients did not achieve PASI 50. The mean PASI score before therapy was 16.73 points, and after 16 ± 4 weeks — 6.4 points, the mean dynamics was 10.33 points, the median dynamics was 7 points [CI 10.33 ± 4]. All patients achieved PASI 50, 75.3% — PASI 75, 8% — PASI 90, and 16.7% — PASI 100 in the ustekinumab group. The mean PASI score before therapy was 22.17 points, and after 16 weeks — 3.67 points, the mean dynamics was 19.28 points, the median dynamics was 17 points [CI 18.5 ± 3.03]. All patients achieved PASI 50, 47% — PASI 75, and 11% — PASI 90 in the secukinumab group. The median PASI before therapy was 14.29 points, and after 16 ± 4 weeks — 3.71 points, the mean PASI score before therapy was 14.29 points, and after 16 weeks — 3.7 points, the mean dynamics was 10.59 points, the median dynamics was 10 points [CI 10.59 ± 2.27]. Evaluation of indicators via Wilcoxon test has shown statistically significant decrease in the PASI after therapy in all groups (p 0.05). There were no adverse events leading to cessation of therapy during the follow-up period.

Conclusion. All groups have shown decrease in the in EFT thickness and in the PASI score. The most significant dynamics was observed in the ustekinumab group. Research limitations were the small patients sample and the absence of a control group (participants without psoriasis).

Background. Congenital ichthyoses (CIs) are a heterogeneous clinical-etiological group of genodermatoses. Typical clinical symptoms of this disease, regardless of the form, are generalized erythroderma, peeling, itching, hyperkeratosis, severe structural and functional disorders of the epidermal barrier, other organs and systems. Patients have an extremely low quality of life due to changes in appearance, discomfort, constant disease symptoms. Thus far, there are no effective treatment methods for ichthyosis. That is why scientific search for new therapies is the topical issue in pediatrics and pediatric dermatology.

Objective. The aim of the study is to examine the cell-mediated immunity state in patients with CI via assessment of the pattern of lymphocyte subpopulations in peripheral blood. The research was conducted to study the content of the main and small lymphocyte subpopulations in 86 patients with established diagnosis of CI aged from 1 month to 18 years. The diagnosis was made according to the clinical data and the results of molecular genetic testing. Comparative analysis of blood immunological indicators in children with CI and in patients with other immunemediated chronic dermatoses: atopic dermatitis (AD; n = 68) and psoriasis vulgaris (n = 55).

Methods. The level of T lymphocytes, T helpers (Th), cytotoxic T lymphocytes (Tc), B lymphocytes, NK cells, Treg-cells (Treg), activated T helpers (Thact), Th17 lymphocytes in peripheral blood was evaluated via flow cytometry using monoclonal antibodies. Statistical analysis was performed via Statistica 10.0. Differences between the groups were assessed via Mann-Whitney non-parametric test, differences were considered significant at p < 0.05.

Results. A significant increase of activated T-helpers level in peripheral blood was revealed in patients with CI and psoriasis compared to children with AD (p < 0.001), as well as an increased levels of B-lymphocytes and Treg in children with CI (p < 0.05).

Conclusion. Children with CI have shown some features of cell-mediated immunity such as: pathological activation of Th lymphocytes, impaired terminal differentiation of naive CD4+ cells to Thact, Treg, Th17 lymphocytes and their proliferation. Comparative analysis of mentioned immunological indicators in children with CI, psoriasis and AD has shown comparable results of increased Thact lymphocytes levels in patients in CI and psoriasis groups. This results open up potential of using immunobiological drugs of psoriasis target therapy within the new management strategy for children with CI.

Background. Hypotrichosis is a heritable form of alopecia that causes almost complete scalp hair loss in childhood. The diagnosis is typically established according to medical history and clinical picture. Genetic testing is an additional diagnostic method that allows to establish “hypotrichosis” in cases of ambiguous or subtle clinical signs of the disease, as well as to perform differential diagnosis of this condition with others commonly associated with atopic dermatitis (focal and diffuse alopecia). Clinical diagnosis of hypotrichosis in patients with severe dermatosis is challenging.

Clinical case description. The girl, aged 2 years 4 months, was hospitalized with complaints on extended rash on the body with severe itching, and changes in hair thickness, quality of hair shaft, and hair loss. Severe atopic dermatitis and hypotrichosis were diagnosed. The diagnosis of atopic dermatitis was established clinically (SCORAD — 65), the diagnosis of hypotrichosis (type 6, monilethrix-like hypotrichosis) was confirmed via molecular genetic testing (nucleotide variant c.699C>T in exone 13 of the DSG4 gene (OMIM # 607892)). Patient's mother, brother, and two sisters were diagnosed with the nucleotide variant chr18:31409487C>T in heterozygous state in the DSG4 gene. Mother and brother had no clinical manifestations, while both sisters had mild scalp hair damage, as well as eyebrows and eyelashes, since birth. There were no clinical manifestations of atopic dermatitis in parents and other children in the family.

Conclusion. Hypotrichosis clinical signs can be subtled, smoothed, or imitate the symptoms of other comorbid conditions, especially in patients with comorbidities or severe dermatosis. Also worth noting is that changes in certain genes can aggravate the course of atopic dermatitis. In this clinical case, mutation in the DSG4 gene leads to epidermal barrier failure by disrupting the synthesis of desmosomes transmembrane components. Thus, geneticist consultation and genetic testing (search for changes in certain genes) are crucial in such cases.

Background. Netherton syndrome is a severe autosomal recessive disease based not only on genetically determined keratinization disorders, but also on immune system dysregulation.

Clinical case description. Boy K., 9 years old, diagnosed with severe atopic dermatitis and revealed Netherton syndrome during examinations. The dupilumab was administered due to the presence of severe polysensitization and clinical signs of allergic process. Wave-like course of the disease was observed during this therapy. Patient had acute exacerbation — generalized pustular rash — at the 7th month of treatment. The therapy with secukinumab was initiated according to the foreign literature on pathogenetic treatment of Netherton syndrome with interleukin (IL) 17 inhibitor. It has shown positive dynamics. Currently patient is administered with the combined therapy of IL-17 and IL-4/13 inhibitors with significant positive effect.

Conclusion. Genetically engineered biologic drugs targeting both the Th17 and Th2 have shown their efficacy in Netherton syndrome management.

Background. Atopic dermatitis (AD) manifests during the first year of life in majority of all cases. The early disease onset is associated with the development of comorbid atopic conditions within the «atopic march» phenomenon. The AD pathogenesis is associated with genetic predisposition, epidermal barrier dysfunction, and immune dysregulation. T2-inflammation specifically determines the entire immune cascade of inflammatory reactions, and, thus, dictates the need of early drug intervention to modify the disease course. Clinical case description. This article presents two clinical cases of severe AD in children under 6 years of age. The treatment of both cases included genetically engineered biologic drug dupilumab. Continuous therapy for 4–5 months made it possible to relieve the skin manifestations of the disease.

Conclusion. AD, manifesting in infancy, is associated with high risk of developing other atopic spectrum diseases in older age. The timely onset of biological therapy allows us to affect immune dysregulation, and thereby to prevent the comorbid atopic conditions development.

Background. Rapp-Hodgkin syndrome is a rare genetic disease from the ectodermal dysplasia group. It manifests with damage of ectodermal structures — layer of embrional tissue that provides the development of many organs and tissues in the body, such as: skin, sweat glands, hair, teeth, and nails. Disease symptoms may range from mild to severe and include dental abnormalities, fragile, thin or no hair, abnormal nails, hypohidrosis (due to the reduced number of sweat glands), cleft lips and palate. Hidradenitis suppurativa is a chronic inflammatory disease that predominantly affects apocrine glands areas. This nosology is characterized by painful nodes, abscesses, and fistulas, prone to relapses and leading to scarring.

Clinical case description. The authors present a clinical case demonstrating the combination of Rapp-Hodgkin syndrome and severe hidradenitis suppurativa in 17-year-old male patient.

Conclusion. The heterogeneous clinical findings of hidradenitis suppurativa and history of rare genetic disease result in patients' admissions to various medical specialists. Thus, it leads to delayed verification of the diagnosis and incorrect treatment methods. As a result, patients have persistent cosmetic skin defects, possible complications of irrational treatment, and decreased quality of life by the time of diagnosis.

Background. Pemphigus herpetiformis is a rare atypical bullous dermatosis of autoimmune nature. It is characterized by rashes in the form of plaques with papules and vesicles at peripheral areas, or in the form of grouped papules, vesicles or tense bubbles with clinical similarity to During's herpetiformis dermatitis. Pemphigus herpetiformis diagnosis in pediatric practice is difficult due to the similarity of clinical manifestations to bullous dermatoses of other etiology, the rarity of the disease in children, and small number of scientific publications.

Clinical case description. Clinical case of pemphigus herpetiformis in a child is described. All necessary diagnostic algorithms for diagnosis and therapeutic tactics for patient management are presented. Dapsone and prednisolone were used as first-line drugs during the patient's treatment. They have shown its efficacy in management of such patients.

Conclusion. Differential diagnosis of pemphigus herpetiformis and other bullous dermatoses in children is presented. The results of successful drug treatment are shown.

Background. Linear IgA dermatosis is a rare autoimmune bullous disease characterized by vesiculo-bullous subepidermal lesions (affecting the skin and mucous membranes) and by linear homogeneous IgA deposition in the epidermis basal membrane.

Clinical case description. Clinical case of linear IgA dermatosis in children is presented. Clinical data assessment, histological examination of the skin biopsy (to determine the depth of bullous), immunofluorescent examination (to reveal IgA deposition in the epidermis basal membrane) are crucial for reliable disease diagnosis according to the studies. Altogether it helps to establish the final diagnosis and determine the patient's management. Dapsone is the first-line treatment for this disease, it has proven to be an effective and safe medication.

Conclusion. This case of linear IgA dermatosis is of concern due to disease severity and its rarity in clinical practice. Differential diagnosis is rather complicated and clinically requires high-tech research methods. Only immunofluorescent examination allows to diagnose linear IgA dermatosis accurately. Lesions' regression was achieved due to systemic therapy with dapsone (1.8 mg/kg/day).

Background. Genetically engineered biological therapy has revolutionized the treatment of many chronic inflammatory diseases. It often allows to achieve significant clinical effect and improve the patient's quality of life. However, sometimes it leads to adverse events, and physicians encounter them more often. One of such side effects is paradoxical psoriasis (PP) that can be revealed during the therapy with tumor necrosis factor alpha (TNF-α) inhibitors. PP is the debut or exacerbation of pre-existing psoriasis.

Clinical case description. Patient A., 17 years old, has suffered from ulcerative colitis since 2020; biological therapy with infliximab has been initiated in March 2022. Numerous rashes were revealed, as well as development of confluent alopecia foci on the background of scalp psoriatic damage, during the next hospitalization in December 2022. The patient was examined by dermatologist; diagnosis of PP was established according to the clinical picture and medical history. Skin rashes progressed and ulcerative colitis worsened (diarrheal syndrome, fecal calprotectin levels increased up to 526 μg/g) after cessation of infliximab therapy. Biological therapy with the inhibitor IL-12/23 (ustekinumab) was initiated due to the aggressive cutaneous pathological process and the aggravation of inflammatory bowel disease (IBD) symptoms. The gradual regression of rashes with the restoration of scalp hair growth and ulcerative colitis clinical and laboratory remission were noted during the treatment.

Conclusion. PP is a rare complication that develops during therapy with TNF-α inhibitors, and it is most often observed in patients with IBD. In our case there was aggressive course of psoriasis with severe scalp lesion and hair loss (it is specific type of lesion in such patients). The ustekinumab, inhibitor IL-12/23, treatment efficacy correlates with the literature data on this drug successful use in both nosologies. Ustekinumab can be a first-line therapy in such pediatric patients. This clinical case is the first case in the Russian literature on effective management of PP and ulcerative colitis with ustekinumab in children.