Blepharitis pathophysiology: Difference between revisions

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====Posterior blepharitis====
====Posterior blepharitis====
Posterior blepharitis is often associated with skin condition, such as [[rosacea]], and rosacea is associated with [[sebaceous glands]] abnormalities (meibomian glands are modified sebaceous glands).
Posterior blepharitis is often associated with skin condition, such as [[rosacea]], and 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 altered meibomian gland secretions may result in an impaired lipid layer of the tear film and instability of the tear film. The abnormal secretions may also cause a direct toxic effect on the [[ocular|ocular surface]]. Additionally, the altered lipid composition may result an environment that affect bacterial growth.<ref name=Blepharitis-1> American Academy of Ophthalmology/ eyewiki (2014) http://eyewiki.aao.org/EyeWiki%3AGeneral_disclaimer| Accessed on July 14, 2016 </ref>
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|ocular surface]]. Additionally, it may result an environment that affect bacterial growth.<ref name=Blepharitis-1> American Academy of Ophthalmology/ eyewiki (2014) http://eyewiki.aao.org/EyeWiki%3AGeneral_disclaimer| Accessed on July 14, 2016 </ref>


''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]]. Additionally, over-proliferation may also lead to lid-margin infection causing ocular-surface [[irritation]] and [[symptoms]] of ocular discomfort such as [[itching]] and foreign-body sensation.<ref name="pmid25371637">{{cite journal| author=Bhandari V, Reddy JK| title=Blepharitis: always remember demodex. | journal=Middle East Afr J Ophthalmol | year= 2014 | volume= 21 | issue= 4 | pages= 317-20 | pmid=25371637 | doi=10.4103/0974-9233.142268 | pmc=4219223 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25371637  }} </ref><ref name="pmid15774912">{{cite journal| author=Viswalingam M, Rauz S, Morlet N, Dart JK| title=Blepharokeratoconjunctivitis in children: diagnosis and treatment. | journal=Br J Ophthalmol | year= 2005 | volume= 89 | issue= 4 | pages= 400-3 | pmid=15774912 | doi=10.1136/bjo.2004.052134 | pmc=1772603 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15774912  }} </ref>
''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 of ''Demodex folliculorum'' may lead to lid-margin infection causing ocular-surface [[irritation]] and symptoms of ocular discomfort, such as [[itching]] and foreign-body sensation.<ref name="pmid25371637">{{cite journal| author=Bhandari V, Reddy JK| title=Blepharitis: always remember demodex. | journal=Middle East Afr J Ophthalmol | year= 2014 | volume= 21 | issue= 4 | pages= 317-20 | pmid=25371637 | doi=10.4103/0974-9233.142268 | pmc=4219223 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25371637  }} </ref><ref name="pmid15774912">{{cite journal| author=Viswalingam M, Rauz S, Morlet N, Dart JK| title=Blepharokeratoconjunctivitis in children: diagnosis and treatment. | journal=Br J Ophthalmol | year= 2005 | volume= 89 | issue= 4 | pages= 400-3 | pmid=15774912 | doi=10.1136/bjo.2004.052134 | pmc=1772603 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15774912  }} </ref>


===Associated Conditions===
===Associated Conditions===
Line 35: Line 35:
*[[Trichiasis]]   
*[[Trichiasis]]   
===Gross Pathology===
===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.<ref name="pmid23118519">{{cite journal| author=Benitez-Del-Castillo JM| title=How to promote and preserve eyelid health. | journal=Clin Ophthalmol | year= 2012 | volume= 6 | issue=  | pages= 1689-98 | pmid=23118519 | doi=10.2147/OPTH.S33133 | pmc=3484726 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23118519  }} </ref>
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 [[hyperaemia|conjunctival hyperaemia]] are characteristic findings of blepharitis.<ref name="pmid23118519">{{cite journal| author=Benitez-Del-Castillo JM| title=How to promote and preserve eyelid health. | journal=Clin Ophthalmol | year= 2012 | volume= 6 | issue=  | pages= 1689-98 | pmid=23118519 | doi=10.2147/OPTH.S33133 | pmc=3484726 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=23118519  }} </ref>
===Microscopic Pathology===
===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.<ref name="pmid13274422">{{cite journal| author=THYGESON P, VAUGHAN DG| title=Seborrheic blepharitis. | journal=Trans Am Ophthalmol Soc | year= 1954 | volume= 52 | issue=  | pages= 173-88 | pmid=13274422 | doi= | pmc=1312591 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=13274422  }} </ref>
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.<ref name="pmid13274422">{{cite journal| author=THYGESON P, VAUGHAN DG| title=Seborrheic blepharitis. | journal=Trans Am Ophthalmol Soc | year= 1954 | volume= 52 | issue=  | pages= 173-88 | pmid=13274422 | doi= | pmc=1312591 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=13274422  }} </ref>
On microscopic histopathological analysis, nongranulomatous inflammation with [[neutrophils]], acanthosis, or parakeratosis are characteristic findings of staphylococcal blepharitis.
On microscopic histopathological analysis, nongranulomatous inflammation with [[neutrophils]], acanthosis, or parakeratosis are characteristic findings of staphylococcal blepharitis.<ref name="pmid2087299">{{cite journal| author=Seal D, Ficker L, Ramakrishnan M, Wright P| title=Role of staphylococcal toxin production in blepharitis. | journal=Ophthalmology | year= 1990 | volume= 97 | issue= 12 | pages= 1684-8 | pmid=2087299 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2087299  }} </ref>  
On microscopic evaluation, Demodex mites may reveal on epilated eyelashes of patient with chronic blepharitis.<ref name="pmid2087299">{{cite journal| author=Seal D, Ficker L, Ramakrishnan M, Wright P| title=Role of staphylococcal toxin production in blepharitis. | journal=Ophthalmology | year= 1990 | volume= 97 | issue= 12 | pages= 1684-8 | pmid=2087299 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=2087299  }} </ref>  


===Images===
===Images===

Revision as of 19:28, 15 July 2016

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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 (Staphylococcus aureus or Staphylococcus epidermidis) 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, increasing cholesterol concentration and creating an environment that promotes bacterial growth. It is thought that bacterial toxins and enzymes may also create inflammation. Blepharitis may 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, and 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 of Demodex folliculorum 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 often is associated with systemic diseases, such as:[6][7]

Blepharitis also is associated with ocular diseases, such as:[6][7][8]

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]

Images

The following are gross images associated with blepharitis.

  • Blepharitis [12]

    Blepharitis [12]

  • Infant with blepharitis [13]

    Infant with blepharitis [13]


References

  1. ↑ 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. ↑ 2.0 2.1 Dougherty JM, McCulley JP (1986). "Bacterial lipases and chronic blepharitis". Invest Ophthalmol Vis Sci. 27 (4): 486–91. PMID 3957566.
  3. ↑ American Academy of Ophthalmology/ eyewiki (2014) http://eyewiki.aao.org/EyeWiki%3AGeneral_disclaimer%7C Accessed on July 14, 2016
  4. ↑ 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.
  5. ↑ 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. ↑ 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. ↑ 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.
  8. ↑ Diseases Database (2016). http://www.diseasesdatabase.com/relationship.asp?glngUserChoice=1455&bytRel=2&blnBW=0&strBB=RL&blnClassSort=255 Accessed on July 15, 2016
  9. ↑ 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.
  10. ↑ THYGESON P, VAUGHAN DG (1954). "Seborrheic blepharitis". Trans Am Ophthalmol Soc. 52: 173–88. PMC 1312591. PMID 13274422.
  11. ↑ Seal D, Ficker L, Ramakrishnan M, Wright P (1990). "Role of staphylococcal toxin production in blepharitis". Ophthalmology. 97 (12): 1684–8. PMID 2087299.
  12. ↑ Wikipedia (2016) https://en.wikipedia.org/wiki/Blepharitis#/media/File:Infant_with_blepharitis_on_the_right_side.jpg%7C Accessed on July 12, 2016
  13. ↑ Wikipedia (2016) https://en.wikipedia.org/wiki/Blepharitis#/media/File:Infant_with_blepharitis_on_the_right_side.jpg%7C Accessed on July 12, 2016

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