PATHOMORPHOLOGY OF APHTHOUS STOMATITIS ASSOCIATED WITH SECONDARY IMMUNODEFICIENCY IN SCHOOL-AGE CHILDREN

Introduction . Aphthous stomatitis is one of the most common inflammatory and ulcerative diseases of the oral mucosa in children. In school-age children with secondary immunodeficiency, aphthous lesions may demonstrate a prolonged, recurrent, and clinically severe course. Impairment of cellular and humoral immunity, reduced mucosal resistance, nutritional deficiencies, chronic infections, and systemic diseases contribute to persistent inflammation and delayed epithelial regeneration.To summarize the principal pathomorphological features of aphthous stomatitis developing in school-age children with secondary immunodeficiency. A narrative review of scientific literature concerning the pathogenesis, immunological mechanisms, and morphological characteristics of aphthous stomatitis was performed. Publications describing oral mucosal lesions in patients with acquired immune dysfunction, chronic infections, nutritional deficiencies, and other causes of secondary immunodeficiency were analyzed. Particular attention was paid to epithelial alterations, inflammatory-cell composition, microcirculatory disorders, stromal changes, and tissue regeneration.Aphthous stomatitis associated with secondary immunodeficiency is characterized by epithelial degeneration, focal necrosis, ulcer formation, fibrinous-necrotic exudation, inflammatory infiltration, vascular congestion, edema, and impaired reparative processes. The inflammatory infiltrate commonly contains lymphocytes, macrophages, neutrophils, and plasma cells. Immune dysregulation involving T lymphocytes and pro-inflammatory cytokines promotes epithelial injury and prolongs ulcer healing.Secondary immunodeficiency substantially modifies the morphological course of aphthous stomatitis in school-age children. The lesions demonstrate more pronounced epithelial destruction, persistent inflammatory infiltration, microcirculatory impairment, and delayed regeneration. Recognition of these features is important for differential diagnosis and the selection of combined immunological and local therapeutic approaches.