Autosomal recessive hyper IgE syndrome 2 (AR-HIES, also hyperimmunoglobulin E syndrome type 2) is a very rare primary immunodeficiency syndrome caused by a mutaion in the DOCK8 gene. The syndrome is characterized by severely elevated immunoglobulin E (IgE) levels in the blood, recurrent staphylococcal skin abscesses, and recurrent pneuomia. The same features also occur in the more common autosomal dominant HIES syndrome (type1). HIES type 2 accounts for only a small minority of HIES cases; approximately 130 affected families have been reported to date. In contrast to HIES type 1, the type 2 variant is characterized by extreme hypereosinophilia, susceptibility to viral infections such as herpes simplex and molluscum contagiosum, central nervous system involvement, T-cell defects, and a high mortality rate. The dental, skeletal, connective tissue, and facial features seen in AD-HIES are absent in AR-HIES.