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 caused by allergens and lice that affect the eyelashes.[1][2]
Pathophysiology
Pathogenesis
Anterior blepharitis
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. Further, following bacterial colonization, bacterial lipase changes meibomian gland secretions and increasing cholesterol concentration. These changes may result an environment that promotes bacterial growth. It is thought that bacterial toxins and enzymes may also create an inflammation. Blepharitis may also caused by allergic response to bacterial antigens (mostly staphylococcal antigens).[1][2]
Posterior blepharitis
Posterior blepharitis is often associated with skin condition, such as rosacea. Rosacea is associated with sebaceous glands abnormalities (meibomian glands are modified sebaceous glands). The exact pathogenesis of posterior blepharitis is not fully understood. It is thought that the abnormal meibomian gland secretions may cause a direct toxic effect on the ocular surface. Additionally, it may result an environment that affect bacterial growth.[3]
Demodex folliculorum is an external parasite in hair follicles, sebaceous glands, and meibomian glands. The exact pathogenesis of chronic blepharitis caused by Demodex folliculorum is not fully understood. It is thought that Demodex folliculorum may infest the meibomian and sebaceous glands. Over-proliferation may lead to lid-margin infection causing ocular-surface irritation and symptoms of ocular discomfort, such as itching and foreign-body sensation.[4][5]
Associated Conditions
Blepharitis is associated with systemic diseases, such as:[6][7]
Blepharitis is associated with ocular diseases, such as:[6][7][8]
- 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, perivascular lymphohistocytosis, mononuclear cellular infiltrates, and spongiosis in eyelids (superfeicial dermis) are characteristic findings of seborrheic blepharitis.[10]
On microscopic histopathological analysis, nongranulomatous inflammation with neutrophils, acanthosis, or parakeratosis are characteristic findings of staphylococcal blepharitis.[11]
On microscopic histopathological analysis, inflammatory changes, epithelial hyperplasia, and follicular plugging are characteristic findings ofchronic blepharitis caused by Demodex folliculorum.[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.
