Pityriasis lichenoides in children: modern understanding of the problem

Introduction. The article is devoted to such rare skin disease as pityriasis lichenoides. The relevance of the problem is associated with the lack of clear terminology and classification in domestic pediatric practice, and as a consequence, with difficult diagnostic search. In foreign terminology, pityriasis lichenoides is a unique group of inflammatory skin diseases, including pityriasis lichenoides et varioliformis acuta (PLEVA), febrile ulceronecrotic Mucha-Habermann disease (subtype of PLEVA or FUMHD) and pityriasis lichenoides chronica (PLC). Features of the disease are considered taking into account this classification. Objective. To present a review of current data and results of scientific studies devoted to the investigation of clinical types of pityriasis lichenoides. Results. A comprehensive review of all cases of pityriasis lichenoides in pediatric patients described in the English-language literature and published in PubMed database from 1998 to 2024 was carried out, features of epidemiology, clinical manifestations and prognosis of the disease in children were summarized. The pathogenesis of pityriasis lichenoides, including the relationship with infectious agents, drugs and immunization, was discussed, the results of scientific studies, devoted to the investigation of pityriasis lichenoides as a lymphoproliferative disease and discussing options for treatment and prognosis, were presented. Phototherapy, systemic antibacterial drugs and topical corticosteroids are the main methods of treatment for PLEVA and chronic pityriasis lichenoides, immunosuppressive agents — for FUMHD. Conclusion. Pityriasis lichenoides is a diagnostic and therapeutic problem for a dermatovenereologist. Diagnosis of the disease is based on systematization of anamnestic, clinical and laboratory data confirmed by pathomorphological examination. No specific treatment of pityriasis lichenoides has been developed. The disease is successfully treated with corticosteroids, antibiotics, immunosuppressive agents and narrow-band UVB phototherapy. The latter showed the best results. Due to the increased number of reports on the transformation of pityriasis lichenoides into T-cell lymphoma, it is important to monitor patients for the risk of developing lymphoproliferative disorders.