Background: Recurrent wheezy chest is a common complaint in pediatric practice. Vitamin D is a potent immunomodulator in allergic diseases as wheezy chest and asthma. The prevalence of vitamin D deficiency has been increasing in Egypt leading to significant morbidities.Objectives: This study aimed to assess serum 25 hydroxy (OH) Vitamin D level in preschool children with recurrent wheezy chest, and to assess its relation to the recurrence, severity, and level of control of the wheezing episodes.Methods: The study included 100 preschool children (aged 2 to 5 years), of both sexes, recruited from the Emergency department, Allergy and Pulmonology units at Assiut University Children Hospital, Egypt. They should have at least 3 documented episodes of wheeze, cough, and difficulty breathing in the last year with clinical improvement on inhaled short-acting beta 2 agonists. Patients were subjected to questionnaire-based history, clinical examination, and laboratory investigations (complete blood count (CBC) with the absolute eosinophil count, serum total IgE level, and serum 25 hydroxy (OH) Vitamin D level). Pediatric Respiratory Assessment Measure (PRAM score) for assessment of the severity of the wheezing episodes and Global Initiative for Asthma (GINA) based level of asthma control for children 5 years and younger were applied. The patients were grouped according to PRAM score to mild, moderate and severe episodes and according to vitamin D level as sufficient and below-sufficient groups (including deficient and insufficient patients).Results: 25(OH) Vitamin D level was below-sufficient in 53% of the studied patients (deficient in 32% and insufficient in 21%). PRAM score was significantly lower in patients with sufficient 25(OH) Vitamin D level versus those with below-sufficient level (p < 0.025). There was a significant negative correlation between PRAM score and 25 (OH) Vitamin D level (r = -0.334, p = 0.001).Conclusion: There is an inverse relationship between 25(OH)vitamin D level and parameters of asthma severity, as well as with the level of asthma control in preschool children with recurrent wheezy chest.Keywords: Vitamin D, recurrent wheezy chest, preschool childre
