What is anterior blepharitis?
Anterior blepharitis affects the outside of the eyelid where eyelashes are attached to the lid. Anterior blepharitis can be caused by bacterial infection; e.g.: staphylococcal anterior blepharitis; or viral infection. Scaling and crusting at the base of the eye lashes is typical. If left untreated, anterior blepharitis can lead to thickened and inward-turned (lid entropion) or outward-turned (lid ectropion) eyelids. Vision can be affected if inwardly-turned lashes damage the cornea. Outward-turned lids can expose the highly sensitive mucosal tissue of the lid, causing extreme discomfort.
Seborrheic anterior blepharitis causes dandruff around the base of the eye lids and greasy scales at the eye lashes.
Staphylococcal anterior blepharitis is caused by staphylococci bacteria found on the eye lashes. Crusting is a common symptom (Lowery, 2014).
Demodex folliculorum and demodex brevis are mites that are found at the roots of the eye lashes, meibomian glands, or sebaceous glands of the skin. Demodex folliculorum live in colonies and cause anterior blepharitis and Demodex brevis usually live alone and cause posterior blepharitis and meibomian gland dysfunction (MGD). The mites are characterized by cylindrical dandruff at the base of the lashes (Cheng, Sheha & Tseng, 2015).
References
Recent advances on ocular demodex infestation
Cheng, A., Sheha, H., & Tseng, S.
Current Opinion in Ophthalmology,
2015 Jul;26(4):295-300. doi: 10.1097/ICU.0000000000000168
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Adult Blepharitis Clinical Presentation
Lowery, R. (2014, February 20). Retrieved September 16, 2015, from http://emedicine.medscape.com/article/1211763-clinical#b4