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Comedo

January 01, 1970

"Blackhead" redirects here. For other uses, see Blackhead (disambiguation).

A comedo is a clogged hair follicle (pore) in the skin.[2] Keratin (skin debris) combines with oil to block the follicle.[3] A comedo can be open (blackhead) or closed by skin (whitehead) and occur with or without acne.[3] The word "comedo" comes from the Latin comedere, meaning "to eat up", and was historically used to describe parasitic worms; in modern medical terminology, it is used to suggest the worm-like appearance of the expressed material.[1]

Comedo
Other namesPlural: comedones[1]
Illustration comparing a normal skin pore with a whitehead and a blackhead
SpecialtyDermatology

The chronic inflammatory condition that usually includes comedones, inflamed papules, and pustules (pimples) is called acne.[3][4] Infection causes inflammation and the development of pus.[2] Whether a skin condition classifies as acne depends on the number of comedones and infection.[4] Comedones should not be confused with sebaceous filaments.

Comedo-type ductal carcinoma in situ (DCIS) is not related to the skin conditions discussed here. DCIS is a noninvasive form of breast cancer, but comedo-type DCIS may be more aggressive, so may be more likely to become invasive.[5]

Causes edit

Oil production in the sebaceous glands increases during puberty, causing comedones and acne to be common in adolescents.[3][4] Acne is also found premenstrually and in women with polycystic ovarian syndrome.[3] Smoking may worsen acne.[3]

Oxidation rather than poor hygiene or dirt causes blackheads to be black.[2] Washing or scrubbing the skin too much could make it worse, by irritating the skin.[2] Touching and picking at comedones might cause irritation and spread infection.[2] What effect shaving has on the development of comedones or acne is unclear.[2]

Some skin products might increase comedones by blocking pores,[2] and greasy hair products (such as pomades) can worsen acne.[3] Skin products that claim to not clog pores may be labeled noncomedogenic or nonacnegenic.[6] Make-up and skin products that are oil-free and water-based may be less likely to cause acne.[6] Whether dietary factors or sun exposure make comedones better, worse, or neither is unknown.[3]

A hair that does not emerge normally, an ingrown hair, can also block the pore and cause a bulge or lead to infection (causing inflammation and pus).[4]

Genes may play a role in the chances of developing acne.[3] Comedones may be more common in some ethnic groups.[3][7] People of Latino and recent African descent may experience more inflammation in comedones, more comedonal acne, and earlier onset of inflammation.[3][7]

Pathophysiology edit

 
Multiple open comedones at the nasolabial fold and the alar of the nose

Comedones are associated with the pilosebaceous unit, which includes a hair follicle and sebaceous gland. These units are mostly on the face, neck, upper chest, shoulders, and back.[3] Excess keratin combined with sebum can plug the opening of the follicle.[3][8] This small plug is called a microcomedo.[8] Androgens increase sebum (oil) production.[3] If sebum continues to build up behind the plug, it can enlarge and form a visible comedo.[8]

A comedo may be open to the air ("blackhead") or closed by skin ("whitehead").[2] Being open to the air causes oxidation of the melanin pigment, which turns it black.[9][2] Cutibacterium acnes is the suspected infectious agent in acne.[3] It can proliferate in sebum and cause inflamed pustules (pimples) characteristic of acne.[3] Nodules are inflamed, painful, deep bumps under the skin.[3]

Comedones that are 1 mm or larger are called macrocomedones.[10] They are closed comedones and are more frequent on the face than neck.[11]

Solar comedones (sometimes called senile comedones) are related to many years of exposure to the sun, usually on the cheeks, not to acne-related pathophysiology.[12]

Management edit

Using nonoily cleansers and mild soap may not cause as much irritation to the skin as regular soap.[13][14] Blackheads can be removed across an area with commercially available pore-cleansing strips (which can still damage the skin by leaving the pores wide open and ripping excess skin) or the more aggressive cyanoacrylate method used by dermatologists.[15]

Squeezing blackheads and whiteheads can remove them, but can also damage the skin.[2] Doing so increases the risk of causing or transmitting infection and scarring, as well as potentially pushing any infection deeper into the skin.[2] Comedo extractors are used with careful hygiene in beauty salons and by dermatologists, usually after using steam or warm water.[2]

Complementary medicine options for acne in general have not been shown to be effective in trials.[3] These include aloe vera, pyridoxine (vitamin B6), fruit-derived acids, kampo (Japanese herbal medicine), ayurvedic herbal treatments, and acupuncture.[3]

Some acne treatments target infection specifically, but some treatments are aimed at the formation of comedones, as well.[16] Others remove the dead layers of the skin and may help clear blocked pores.[2][3][4]

Dermatologists can often extract open comedones with minimal skin trauma, but closed comedones are more difficult.[3] Laser treatment for acne might reduce comedones,[17] but dermabrasion and laser therapy have also been known to cause scarring.[10]

Macrocomedones (1 mm or larger) can be removed by a dermatologist using surgical instruments or cauterized with a device that uses light.[10][11] The acne drug isotretinoin can cause severe flare-ups of macrocomedones, so dermatologists recommend removal before starting the drug and during treatment.[10][11]

Some research suggests that the common acne medications retinoids and azelaic acid are beneficial and do not cause increased pigmentation of the skin.[18] If using a retinoid, sunscreen is recommended.

Rare conditions edit

Favre–Racouchot syndrome occurs in sun-damaged skin and includes open and closed comedones.[19]

Nevus comedonicus or comedo nevus is a benign hamartoma (birthmark) of the pilosebaceous unit around the oil-producing gland in the skin.[20] It has widened open hair follicles with dark keratin plugs that resemble comedones, but they are not actually comedones.[20][21]

Dowling–Degos disease is a genetic pigment disorder that includes comedo-like lesions and scars.[22][23]

Familial dyskeratotic comedones are a rare autosomal-dominant genetic condition, with keratotic (tough) papules and comedo-like lesions.[24][25]

References edit

  1. ^ a b . Oxford Dictionary. Oxford University Press. Archived from the original on December 21, 2013. Retrieved 16 June 2013.
  2. ^ a b c d e f g h i j k l m Informed Health Online. "Acne". Fact sheet. Institute for Quality and Efficiency in Health Care (IQWiG). Retrieved 9 June 2013.
  3. ^ a b c d e f g h i j k l m n o p q r s t u Williams, HC; Dellavalle, RP; Garner, S (Jan 28, 2012). "Acne vulgaris". Lancet. 379 (9813): 361–72. doi:10.1016/S0140-6736(11)60321-8. PMID 21880356. S2CID 205962004.
  4. ^ a b c d e Purdy, Sarah; De Berker, David (2011). "Acne vulgaris". BMJ Clinical Evidence. 2011: 1714. PMC 3275168. PMID 21477388.
  5. ^ National Cancer Institute (2002). "Breast cancer treatment". Physician Desk Query. National Cancer Institute. PMID 26389187. Retrieved 13 June 2013.
  6. ^ a b British Association of Dermatologists. . Patient information leaflet. British Association of Dermatologists. Archived from the original on 2013-10-04. Retrieved 12 June 2013.
  7. ^ a b Davis, EC; Callender, VD (April 2010). "A review of acne in ethnic skin: pathogenesis, clinical manifestations, and management strategies". The Journal of Clinical and Aesthetic Dermatology. 3 (4): 24–38. PMC 2921746. PMID 20725545.
  8. ^ a b c Burkhart, CG; Burkhart, CN (October 2007). "Expanding the microcomedone theory and acne therapeutics: Propionibacterium acnes biofilm produces biological glue that holds corneocytes together to form plug". Journal of the American Academy of Dermatology. 57 (4): 722–4. doi:10.1016/j.jaad.2007.05.013. PMID 17870436.
  9. ^ Kumar, Vinay; Abbas, Abul K.; Aster, Jon C.; Turner, Jerrold R.; Perkins, James A.; Robbins, Stanley L.; Cotran, Ramzi S., eds. (2021). Robbins & Cotran Pathologic Basis of Disease (10th ed.). Philadelphia, PA: Elsevier. p. 1165. ISBN 978-0-323-53113-9.
  10. ^ a b c d Wise, EM; Graber, EM (November 2011). "Clinical pearl: comedone extraction for persistent macrocomedones while on isotretinoin therapy". The Journal of Clinical and Aesthetic Dermatology. 4 (11): 20–1. PMC 3225139. PMID 22132254.
  11. ^ a b c Primary Care Dermatology Society. "Acne: macrocomedones". Clinical Guidance. Primary Care Dermatology Society. Retrieved 12 June 2013.
  12. ^ DermNetNZ. "Solar comedones". New Zealand Dermatological Society. Retrieved 16 June 2013.
  13. ^ Poli, F (Apr 15, 2002). "[Cosmetic treatments and acne]". La Revue du Praticien. 52 (8): 859–62. PMID 12053795.
  14. ^ Korting, HC; Ponce-Pöschl, E; Klövekorn, W; Schmötzer, G; Arens-Corell, M; Braun-Falco, O (Mar–Apr 1995). "The influence of the regular use of a soap or an acidic syndet bar on pre-acne". Infection. 23 (2): 89–93. doi:10.1007/bf01833872. PMID 7622270. S2CID 39430391.
  15. ^ Pagnoni, A; Kligman, AM; Stoudemayer, T (1999). "Extraction of follicular horny impactions the face by polymers. Efficacy and safety of a cosmetic pore-cleansing strip (Bioré)". Journal of Dermatological Treatment. 10 (1): 47–52. doi:10.3109/09546639909055910.
  16. ^ Gollnick, HP; Krautheim, A (2003). "Topical treatment in acne: current status and future aspects". Dermatology. 206 (1): 29–36. doi:10.1159/000067820. PMID 12566803. S2CID 11179291.
  17. ^ Orringer, JS; Kang, S; Hamilton, T; Schumacher, W; Cho, S; Hammerberg, C; Fisher, GJ; Karimipour, DJ; Johnson, TM; Voorhees, JJ (Jun 16, 2004). "Treatment of acne vulgaris with a pulsed dye laser: a randomized controlled trial". JAMA: The Journal of the American Medical Association. 291 (23): 2834–9. doi:10.1001/jama.291.23.2834. PMID 15199033.
  18. ^ Woolery-Lloyd, HC; Keri, J; Doig, S (Apr 1, 2013). "Retinoids and azelaic Acid to treat acne and hyperpigmentation in skin of color". Journal of Drugs in Dermatology. 12 (4): 434–7. PMID 23652891.  
  19. ^ Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. p. 1847. ISBN 978-1-4160-2999-1.
  20. ^ a b Zarkik, S; Bouhllab, J; Methqal, A; Afifi, Y; Senouci, K; Hassam, B (Jul 15, 2012). "Keratoacanthoma arising in nevus comedonicus". Dermatology Online Journal. 18 (7): 4. doi:10.5070/D38XZ7951S. PMID 22863626.
  21. ^ DermNetNZ. "Comedo Naevus". New Zealand Dermatological Society. Retrieved 16 June 2013.
  22. ^ Bhagwat, PV; Tophakhane, RS; Shashikumar, BM; Noronha, TM; Naidu, V (Jul–Aug 2009). "Three cases of Dowling Degos disease in two families" (PDF). Indian Journal of Dermatology, Venereology and Leprology. 75 (4): 398–400. doi:10.4103/0378-6323.53139. PMID 19584468.
  23. ^ Khaddar, RK; Mahjoub, WK; Zaraa, I; Sassi, MB; Osman, AB; Debbiche, AC; Mokni, M (January 2012). "[Extensive Dowling-Degos disease following long term PUVA therapy]". Annales de Dermatologie et de Vénéréologie. 139 (1): 54–7. doi:10.1016/j.annder.2011.10.403. PMID 22225744.
  24. ^ Hallermann, C; Bertsch, HP (Jul–Aug 2004). "Two sisters with familial dyskeratotic comedones". European Journal of Dermatology. 14 (4): 214–5. PMID 15319152.
  25. ^ OMIM. "Comedones, familial dyskeratotic". OMIM database. OMIM. Archived from the original on 15 June 2013. Retrieved 13 June 2013.

External links edit

January 01, 1970
comedo, blackhead, redirects, here, other, uses, blackhead, disambiguation, comedo, clogged, hair, follicle, pore, skin, keratin, skin, debris, combines, with, block, follicle, comedo, open, blackhead, closed, skin, whitehead, occur, with, without, acne, word,. Blackhead redirects here For other uses see Blackhead disambiguation A comedo is a clogged hair follicle pore in the skin 2 Keratin skin debris combines with oil to block the follicle 3 A comedo can be open blackhead or closed by skin whitehead and occur with or without acne 3 The word comedo comes from the Latin comedere meaning to eat up and was historically used to describe parasitic worms in modern medical terminology it is used to suggest the worm like appearance of the expressed material 1 ComedoOther namesPlural comedones 1 Illustration comparing a normal skin pore with a whitehead and a blackheadSpecialtyDermatology The chronic inflammatory condition that usually includes comedones inflamed papules and pustules pimples is called acne 3 4 Infection causes inflammation and the development of pus 2 Whether a skin condition classifies as acne depends on the number of comedones and infection 4 Comedones should not be confused with sebaceous filaments Comedo type ductal carcinoma in situ DCIS is not related to the skin conditions discussed here DCIS is a noninvasive form of breast cancer but comedo type DCIS may be more aggressive so may be more likely to become invasive 5 Contents 1 Causes 2 Pathophysiology 3 Management 4 Rare conditions 5 References 6 External linksCauses editOil production in the sebaceous glands increases during puberty causing comedones and acne to be common in adolescents 3 4 Acne is also found premenstrually and in women with polycystic ovarian syndrome 3 Smoking may worsen acne 3 Oxidation rather than poor hygiene or dirt causes blackheads to be black 2 Washing or scrubbing the skin too much could make it worse by irritating the skin 2 Touching and picking at comedones might cause irritation and spread infection 2 What effect shaving has on the development of comedones or acne is unclear 2 Some skin products might increase comedones by blocking pores 2 and greasy hair products such as pomades can worsen acne 3 Skin products that claim to not clog pores may be labeled noncomedogenic or nonacnegenic 6 Make up and skin products that are oil free and water based may be less likely to cause acne 6 Whether dietary factors or sun exposure make comedones better worse or neither is unknown 3 A hair that does not emerge normally an ingrown hair can also block the pore and cause a bulge or lead to infection causing inflammation and pus 4 Genes may play a role in the chances of developing acne 3 Comedones may be more common in some ethnic groups 3 7 People of Latino and recent African descent may experience more inflammation in comedones more comedonal acne and earlier onset of inflammation 3 7 Pathophysiology edit nbsp Multiple open comedones at the nasolabial fold and the alar of the nose Comedones are associated with the pilosebaceous unit which includes a hair follicle and sebaceous gland These units are mostly on the face neck upper chest shoulders and back 3 Excess keratin combined with sebum can plug the opening of the follicle 3 8 This small plug is called a microcomedo 8 Androgens increase sebum oil production 3 If sebum continues to build up behind the plug it can enlarge and form a visible comedo 8 A comedo may be open to the air blackhead or closed by skin whitehead 2 Being open to the air causes oxidation of the melanin pigment which turns it black 9 2 Cutibacterium acnes is the suspected infectious agent in acne 3 It can proliferate in sebum and cause inflamed pustules pimples characteristic of acne 3 Nodules are inflamed painful deep bumps under the skin 3 Comedones that are 1 mm or larger are called macrocomedones 10 They are closed comedones and are more frequent on the face than neck 11 Solar comedones sometimes called senile comedones are related to many years of exposure to the sun usually on the cheeks not to acne related pathophysiology 12 Management editUsing nonoily cleansers and mild soap may not cause as much irritation to the skin as regular soap 13 14 Blackheads can be removed across an area with commercially available pore cleansing strips which can still damage the skin by leaving the pores wide open and ripping excess skin or the more aggressive cyanoacrylate method used by dermatologists 15 Squeezing blackheads and whiteheads can remove them but can also damage the skin 2 Doing so increases the risk of causing or transmitting infection and scarring as well as potentially pushing any infection deeper into the skin 2 Comedo extractors are used with careful hygiene in beauty salons and by dermatologists usually after using steam or warm water 2 Complementary medicine options for acne in general have not been shown to be effective in trials 3 These include aloe vera pyridoxine vitamin B6 fruit derived acids kampo Japanese herbal medicine ayurvedic herbal treatments and acupuncture 3 Some acne treatments target infection specifically but some treatments are aimed at the formation of comedones as well 16 Others remove the dead layers of the skin and may help clear blocked pores 2 3 4 Dermatologists can often extract open comedones with minimal skin trauma but closed comedones are more difficult 3 Laser treatment for acne might reduce comedones 17 but dermabrasion and laser therapy have also been known to cause scarring 10 Macrocomedones 1 mm or larger can be removed by a dermatologist using surgical instruments or cauterized with a device that uses light 10 11 The acne drug isotretinoin can cause severe flare ups of macrocomedones so dermatologists recommend removal before starting the drug and during treatment 10 11 Some research suggests that the common acne medications retinoids and azelaic acid are beneficial and do not cause increased pigmentation of the skin 18 If using a retinoid sunscreen is recommended Rare conditions editFavre Racouchot syndrome occurs in sun damaged skin and includes open and closed comedones 19 Nevus comedonicus or comedo nevus is a benign hamartoma birthmark of the pilosebaceous unit around the oil producing gland in the skin 20 It has widened open hair follicles with dark keratin plugs that resemble comedones but they are not actually comedones 20 21 Dowling Degos disease is a genetic pigment disorder that includes comedo like lesions and scars 22 23 Familial dyskeratotic comedones are a rare autosomal dominant genetic condition with keratotic tough papules and comedo like lesions 24 25 References edit a b Comedo Oxford Dictionary Oxford University Press Archived from the original on December 21 2013 Retrieved 16 June 2013 a b c d e f g h i j k l m Informed Health Online Acne Fact sheet Institute for Quality and Efficiency in Health Care IQWiG Retrieved 9 June 2013 a b c d e f g h i j k l m n o p q r s t u Williams HC Dellavalle RP Garner S Jan 28 2012 Acne vulgaris Lancet 379 9813 361 72 doi 10 1016 S0140 6736 11 60321 8 PMID 21880356 S2CID 205962004 a b c d e Purdy Sarah De Berker David 2011 Acne vulgaris BMJ Clinical Evidence 2011 1714 PMC 3275168 PMID 21477388 National Cancer Institute 2002 Breast cancer treatment Physician Desk Query National Cancer Institute PMID 26389187 Retrieved 13 June 2013 a b British Association of Dermatologists Acne Patient information leaflet British Association of Dermatologists Archived from the original on 2013 10 04 Retrieved 12 June 2013 a b Davis EC Callender VD April 2010 A review of acne in ethnic skin pathogenesis clinical manifestations and management strategies The Journal of Clinical and Aesthetic Dermatology 3 4 24 38 PMC 2921746 PMID 20725545 a b c Burkhart CG Burkhart CN October 2007 Expanding the microcomedone theory and acne therapeutics Propionibacterium acnes biofilm produces biological glue that holds corneocytes together to form plug Journal of the American Academy of Dermatology 57 4 722 4 doi 10 1016 j jaad 2007 05 013 PMID 17870436 Kumar Vinay Abbas Abul K Aster Jon C Turner Jerrold R Perkins James A Robbins Stanley L Cotran Ramzi S eds 2021 Robbins amp Cotran Pathologic Basis of Disease 10th ed Philadelphia PA Elsevier p 1165 ISBN 978 0 323 53113 9 a b c d Wise EM Graber EM November 2011 Clinical pearl comedone extraction for persistent macrocomedones while on isotretinoin therapy The Journal of Clinical and Aesthetic Dermatology 4 11 20 1 PMC 3225139 PMID 22132254 a b c Primary Care Dermatology Society Acne macrocomedones Clinical Guidance Primary Care Dermatology Society Retrieved 12 June 2013 DermNetNZ Solar comedones New Zealand Dermatological Society Retrieved 16 June 2013 Poli F Apr 15 2002 Cosmetic treatments and acne La Revue du Praticien 52 8 859 62 PMID 12053795 Korting HC Ponce Poschl E Klovekorn W Schmotzer G Arens Corell M Braun Falco O Mar Apr 1995 The influence of the regular use of a soap or an acidic syndet bar on pre acne Infection 23 2 89 93 doi 10 1007 bf01833872 PMID 7622270 S2CID 39430391 Pagnoni A Kligman AM Stoudemayer T 1999 Extraction of follicular horny impactions the face by polymers Efficacy and safety of a cosmetic pore cleansing strip Biore Journal of Dermatological Treatment 10 1 47 52 doi 10 3109 09546639909055910 Gollnick HP Krautheim A 2003 Topical treatment in acne current status and future aspects Dermatology 206 1 29 36 doi 10 1159 000067820 PMID 12566803 S2CID 11179291 Orringer JS Kang S Hamilton T Schumacher W Cho S Hammerberg C Fisher GJ Karimipour DJ Johnson TM Voorhees JJ Jun 16 2004 Treatment of acne vulgaris with a pulsed dye laser a randomized controlled trial JAMA The Journal of the American Medical Association 291 23 2834 9 doi 10 1001 jama 291 23 2834 PMID 15199033 Woolery Lloyd HC Keri J Doig S Apr 1 2013 Retinoids and azelaic Acid to treat acne and hyperpigmentation in skin of color Journal of Drugs in Dermatology 12 4 434 7 PMID 23652891 nbsp Rapini Ronald P Bolognia Jean L Jorizzo Joseph L 2007 Dermatology 2 Volume Set St Louis Mosby p 1847 ISBN 978 1 4160 2999 1 a b Zarkik S Bouhllab J Methqal A Afifi Y Senouci K Hassam B Jul 15 2012 Keratoacanthoma arising in nevus comedonicus Dermatology Online Journal 18 7 4 doi 10 5070 D38XZ7951S PMID 22863626 DermNetNZ Comedo Naevus New Zealand Dermatological Society Retrieved 16 June 2013 Bhagwat PV Tophakhane RS Shashikumar BM Noronha TM Naidu V Jul Aug 2009 Three cases of Dowling Degos disease in two families PDF Indian Journal of Dermatology Venereology and Leprology 75 4 398 400 doi 10 4103 0378 6323 53139 PMID 19584468 Khaddar RK Mahjoub WK Zaraa I Sassi MB Osman AB Debbiche AC Mokni M January 2012 Extensive Dowling Degos disease following long term PUVA therapy Annales de Dermatologie et de Venereologie 139 1 54 7 doi 10 1016 j annder 2011 10 403 PMID 22225744 Hallermann C Bertsch HP Jul Aug 2004 Two sisters with familial dyskeratotic comedones European Journal of Dermatology 14 4 214 5 PMID 15319152 OMIM Comedones familial dyskeratotic OMIM database OMIM Archived from the original on 15 June 2013 Retrieved 13 June 2013 External links editRines George Edwin ed 1920 Comedones Encyclopedia Americana What causes blackheads Treatment and Prevention Archived 2020 01 27 at the Wayback Machine Retrieved from https en wikipedia org w index php title Comedo amp oldid 1194566979, wikipedia, wiki, book, books, library,

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