The hyper-IgE syndrome (HIES) is a rare primary immunodeficiency, characterized by eczema, elevated total IgE, and recurrent infections of the skin and respiratory system. These immunologic features are associated with skeletal symptoms like failure of dental shedding, typical facies, scoliosis, hyperextensible joints, and pathologic fractures, defining HIES as a multisystem disorder. Etiology and pathogenesis are still unknown. Diagnosis may be adopted by a mosaic of clinical criteria. On one hand severe atopic dermatitis may be confused with HIES, on the other hand atypical clinical expression of HIES may hamper the diagnosis. Although some clinical features may only be present in older patients, diagnosis should be established early in life to prevent complications, such as pneumatoceles following pneumonia, by intensive antibiotic and antimycotic therapy. Classic HIES seems to follow an autosomal-dominant pattern of inheritance and a candidate-region was identified on chromosome 4q21. Patients from consanguineous families present an autosomal-recessive variation of HIES characterized by the absence of skeletal and dental abnormalities but severe cerebral involvement.