- Anterior blepharitis: Anterior blepharitis affects the outside of the eyelid where the eyelashes attach. Anterior blepharitis can occur as seborrheic or ulcerative.
Seborrheic blepharitis is associated with dandruff. This type typically causes the eyelids to become red and produces waxy scales to build up on the eyelashes, causing the eyes to itch. The scales initially develop due to an abnormal amount and type of tear film being produced by the glands of the eyelids.
Ulcerative blepharitis is less common than seborrheic blepharitis, and usually begins in childhood. It is caused by bacteria. Ulcerative blepharitis is a more severe form that causes hard crusts to form around the eyelashes. These crusts often become matted during sleep, making it difficult to open the eyes in the morning.
- Posterior blepharitis: Posterior blepharitis develops when oil glands in the inner eyelid allow bacteria to grow. It can occur as a result of skin conditions such as acne rosacea and scalp dandruff.
Lavine, Jay B., MD. "The Eye Care Source Book." Contemporary Books, 2001.