Actinic prurigo is a rare, often difficult-to-treat, idiopathic photodermatosis. Actinic prurigo is divided into a hereditary form appearing in the Native American population and a sporadic form occurring in non-Native Americans. We present a 28-year-old Caucasian woman who developed typical clinical signs and symptoms of actinic prurigo, just as had her mother and grandmother. The patient and her mother were HLA-A24 and HLA-DR 4 with the subtype HLA-DRB1*0408. Based on clinical symptoms and the HLA pattern, the diagnosis of actinic prurigo was made. Treatment with thalidomide led to resolution of the disease. This case report of a Caucasian woman suffering from a hereditary form of actinic prurigo questions the established classification of actinic prurigo into a hereditary Native American form and a sporadic form occurring in the non-Native American population.