Blepharitis is characterized by a great variety of clinical manifestations, which often include alterations of the ocular surface. This as well as its tendency to be therapy-resistant and recurrent explains why blepharitis marks a challenge for all ophthalmologists. Occasionally dermatologic diseases represent one of the causes of the disease, thus calling for an interdisciplinary approach. The present article describes the state of the art with regard to pathogenesis and therapy of blepharitis.