A cluster study to classify atopic dermatitis (AD) phenotypes into subgroups is required to better understand and manage the disease owing to the heterogeneity of its clinical features. This study aimed to identify the phenotypic subgroups of childhood AD according to allergic sensitization. In 258 children with AD, hierarchical cluster analysis based on specific immunoglobulin (Ig) E sensitization revealed four distinct clusters. Cluster A (n = 71) revealed no IgE sensitization, whereas cluster B (n = 28) showed sensitization to egg white only. Cluster B was highly associated with early-onset AD (<3 months) and a family history of atopic diseases. Cluster C (n = 68) and D (n = 91), sensitized to multiple foods and inhalants, respectively, showed a higher prevalence of skin infection within the last 1 year than others. Cluster D was related to late-onset AD (>12 months) and had more atopic comorbidities. In addition, cluster D showed the most severely impaired health-related quality of life and more frequent use of immunosuppressants. Therefore, childhood AD can be classified into 4 clusters based on the allergic sensitization status, and clinical phenotypes and treatment strategy may be different according to clusters.