Classification depends on the site of blepharitis which can be either anterior Blepharitis or posterior Blepharitis.
There will be inflammation of the anterior part of the eyelid margin where the eyelashes are attached.
Causes of anterior blepharitis
- Bacterial infection like staphylococcal infection
These bacteria normally present on the eyelid margin and do not cause symptoms but overgrowth of them will lead to infection with symptoms of Blepharitis.
Also infestation of the eyelash with lice like demodex folliculorum can cause anterior Blepharitis.
- Seborrheic Blepharitis
It occur in patient with seborrheic dermatitis (scalp dandruff and eyebrows dandruff). It is characteristic by oily skin and flaking from the scalp or brows.
There will be excessive lipid secretion on the eyelid margins which are broken down by special bacteria called corynebacterium acnes. The breakdown products will cause inflammation of the eyelid margin.
- Other causes of Dermatitis
Herpes Eye Infection,Varicella-Zoster dermatitis, Molluscum contagiosum dermatitis and allergic or contact dermatitis.
Allergy can be caused by many factors like drugs and environmental factors.