Blepharitis pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sara Mehrsefat, M.D. [2]
Overview
The exact pathogenesis of blepharitis is not fully understood. It is thought that blepharitis is caused by either bacterial colonization in the eyelids or meibomian gland dysfunction. Blepharitis may also be caused by allergens and mites that affect the eyelashes.[1][2]
Pathophysiology
Pathogenesis
Anterior blepharitis
Anterior blepharitis is often associated with staphylococcal infection and seborrhoeic dermatitis. The exact pathogenesis of anterior blepharitis is not fully understood. It is thought that blepharitis is caused by bacterial colonization (Staphylococcus aureus or Staphylococcus epidermidis) in the eyelids. Following bacterial colonization, bacterial lipase changes meibomian gland secretions and increases cholesterol concentration. These changes may result in an environment that affects the ocular surface and tear evaporation. It is thought that anterior blepharitis may also be caused by allergic response to bacterial antigens (mostly staphylococcal antigens).[1][2]
Posterior blepharitis
The exact pathogenesis of posterior blepharitis is not fully understood. It is thought that the abnormal meibomian gland secretions may result in posterior blepharitis. Posterior blepharitis is often associated with skin conditions, such as rosacea or seborrhoeic dermatitis. These conditions are associated with sebaceous glands abnormalities. It is thought that the abnormal meibomian gland secretions may cause a direct toxic effect on the ocular surface. Sebaceous glands abnormalities may also result in an environment that affect bacterial growth.[3]
Acute blepharitis
Chronic blepharitis
Additionally, anterior and posterior blepharitis may be caused by Demodex folliculorum. Demodex folliculorum is an external parasite in hair follicles, sebaceous glands, and meibomian glands. The exact pathogenesis of chronic blepharitis caused by the Demodex mites is not fully understood. It is thought that over-proliferation of Demodex folliculorum in meibomian glands may result in lid-margin infection and ocular discomfort.[4][5]
Associated Conditions
Many diseases are associated with blepharitis such as skin, systemic, and ocular disease.
Systemic or skin disease:[6][7]
- Conjunctivitis
- Meibomianitis (inflammation of the meibomian glands)
- Keratitis
- Dry eye syndrome
- Chalazion
- Trichiasis
Gross Pathology
On gross pathology, lid margin swelling, misdirection of lashes, loss of lashes, oily or greasy deposits on lid margins, crusting of anterior lid margin, lid margin hyperaemia, and conjunctival hyperaemia are characteristic findings of blepharitis.[9]
Microscopic Pathology
On microscopic histopathological analysis, hyperkeratinization of the meibomian gland ductal epithelium, mononuclear cellular infiltrates, and spongiosis in eyelids are characteristic findings of seborrheic blepharitis.[10]
On microscopic histopathological analysis, non granulomatous inflammation with neutrophils, acanthosis, or parakeratosis are characteristic findings of staphylococcal blepharitis.[11]
On microscopic histopathological analysis, chronic inflammatory changes, epithelial hyperplasia, and follicular plugging are characteristic findings of chronic blepharitis.[12]
Images
The following are gross images associated with blepharitis.
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![Blepharitis [13]](/images/6/6e/193px-Blepharitis.JPG)
Blepharitis [13]
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![Infant with blepharitis [14]](/images/5/5d/218px-Infant_with_blepharitis_on_the_right_side.jpg)
Infant with blepharitis [14]
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![Demodex folliculorum[12]](/images/f/f1/AMS-10-22714-g001.gif)
Demodex folliculorum[12]
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![Toothpaste-like opaque meibum (meibomian gland dysfunction)[15]](/images/7/75/Meibomian_gland_dysfunction.jpg)
Toothpaste-like opaque meibum (meibomian gland dysfunction)[15]
![Blepharitis [13]](/index.php/File:193px-Blepharitis.JPG)
![Infant with blepharitis [14]](/index.php/File:218px-Infant_with_blepharitis_on_the_right_side.jpg)
![Demodex folliculorum[12]](/index.php/File:AMS-10-22714-g001.gif)
![Toothpaste-like opaque meibum (meibomian gland dysfunction)[15]](/index.php/File:Meibomian_gland_dysfunction.jpg)
References
- ↑ 1.0 1.1 Bunya VY, Brainard DH, Daniel E, Massaro-Giordano M, Nyberg W, Windsor EA; et al. (2013). "Assessment of signs of anterior blepharitis using standardized color photographs". Cornea. 32 (11): 1475–82. doi:10.1097/ICO.0b013e3182a02e0e. PMC 3947496. PMID 24055901.
- ↑ 2.0 2.1 Dougherty JM, McCulley JP (1986). "Bacterial lipases and chronic blepharitis". Invest Ophthalmol Vis Sci. 27 (4): 486–91. PMID 3957566.
- ↑ American Academy of Ophthalmology/ eyewiki (2014) http://eyewiki.aao.org/EyeWiki%3AGeneral_disclaimer%7C Accessed on July 14, 2016
- ↑ Bhandari V, Reddy JK (2014). "Blepharitis: always remember demodex". Middle East Afr J Ophthalmol. 21 (4): 317–20. doi:10.4103/0974-9233.142268. PMC 4219223. PMID 25371637.
- ↑ Viswalingam M, Rauz S, Morlet N, Dart JK (2005). "Blepharokeratoconjunctivitis in children: diagnosis and treatment". Br J Ophthalmol. 89 (4): 400–3. doi:10.1136/bjo.2004.052134. PMC 1772603. PMID 15774912.
- ↑ 6.0 6.1 McCulley JP, Dougherty JM (1985). "Blepharitis associated with acne rosacea and seborrheic dermatitis". Int Ophthalmol Clin. 25 (1): 159–72. PMID 3156100.
- ↑ 7.0 7.1 Nemet AY, Vinker S, Kaiserman I (2011). "Associated morbidity of blepharitis". Ophthalmology. 118 (6): 1062–8. doi:10.1016/j.ophtha.2010.10.015. PMID 21276617.
- ↑ Diseases Database (2016). http://www.diseasesdatabase.com/relationship.asp?glngUserChoice=1455&bytRel=2&blnBW=0&strBB=RL&blnClassSort=255 Accessed on July 15, 2016
- ↑ Benitez-Del-Castillo JM (2012). "How to promote and preserve eyelid health". Clin Ophthalmol. 6: 1689–98. doi:10.2147/OPTH.S33133. PMC 3484726. PMID 23118519.
- ↑ THYGESON P, VAUGHAN DG (1954). "Seborrheic blepharitis". Trans Am Ophthalmol Soc. 52: 173–88. PMC 1312591. PMID 13274422.
- ↑ Seal D, Ficker L, Ramakrishnan M, Wright P (1990). "Role of staphylococcal toxin production in blepharitis". Ophthalmology. 97 (12): 1684–8. PMID 2087299.
- ↑ 12.0 12.1 Wesolowska M, Knysz B, Reich A, Blazejewska D, Czarnecki M, Gladysz A; et al. (2014). "Prevalence of Demodex spp. in eyelash follicles in different populations". Arch Med Sci. 10 (2): 319–24. doi:10.5114/aoms.2014.42585. PMC 4042053. PMID 24904668.
- ↑ Wikipedia (2016) https://en.wikipedia.org/wiki/Blepharitis#/media/File:Infant_with_blepharitis_on_the_right_side.jpg%7C Accessed on July 12, 2016
- ↑ Wikipedia (2016) https://en.wikipedia.org/wiki/Blepharitis#/media/File:Infant_with_blepharitis_on_the_right_side.jpg%7C Accessed on July 12, 2016
- ↑ Tomlinson A, Bron AJ, Korb DR, Amano S, Paugh JR, Pearce EI; et al. (2011). "The international workshop on meibomian gland dysfunction: report of the diagnosis subcommittee". Invest Ophthalmol Vis Sci. 52 (4): 2006–49. doi:10.1167/iovs.10-6997f. PMC 3072162. PMID 21450918.
