Eosinophilic pustular folliculitis (EPF) is a noninfectious eosinophilic infiltration of hair follicles first described 40 years ago. There are 3 variants: classic EPF, immunosuppression-associated (mostly HIV-related), and infancy-associated EPF. EPF has been classified as an AIDS-defining illness. In both children and adults EPF should be viewed as a possible cutaneous sign of immunosuppression. However, it may also be seen in persons with normal immune status. We review EPF on the 40th anniversary of its original description.