Athlete's foot pathophysiology: Difference between revisions
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==Overview== | ==Overview== | ||
*Athlete's foot is caused by a parasitic fungus and is a [[communicable disease]].<ref name=webmd_causes>[http://www.webmd.com/skin-problems-and-treatments/tc/Athletes-Foot-Cause Causes of athlete's foot], at [[WebMD]]</ref> | *Athlete's foot is caused by a [[Parasitism|parasitic]] [[fungus]] and is a [[communicable disease]].<ref name="webmd_causes">[http://www.webmd.com/skin-problems-and-treatments/tc/Athletes-Foot-Cause Causes of athlete's foot], at [[WebMD]]</ref> | ||
*It is typically transmitted in moist environments where people walk barefoot, such as [[shower]]s, bath houses, and locker rooms.<ref name=mayoclinic>{{cite web |title= Athlete's foot |url=http://www.mayoclinic.com/health/athletes-foot/DS00317 |publisher=[[Mayo Clinic]] Health Center}}</ref><ref name=webmd_risks>[http://www.webmd.com/skin-problems-and-treatments/tc/Athletes-Foot-What-Increases-Your-Risk] | |||
*Risk factors for athlete's foot, at[[WebMD]]</ref><ref name=webmd_causes/> | * It is typically transmitted in moist environments where people walk barefoot, such as [[shower]]s, bath houses, and locker rooms.<ref name="mayoclinic">{{cite web |title= Athlete's foot |url=http://www.mayoclinic.com/health/athletes-foot/DS00317 |publisher=[[Mayo Clinic]] Health Center}}</ref><ref name="webmd_risks">[http://www.webmd.com/skin-problems-and-treatments/tc/Athletes-Foot-What-Increases-Your-Risk] | ||
*Risk factors for athlete's foot, at[[WebMD]]</ref><ref name="webmd_causes" /> | |||
* It can also be transmitted by sharing footwear with an infected person, or less commonly, by sharing towels with an infected person. | |||
==Pathophysiology== | ==Pathophysiology== | ||
===Transmission=== | ===Transmission=== | ||
*The various parasitic fungi that cause athlete's foot can also cause skin infections on other areas of the body, most often under [[toenail]]s ([[onychomycosis]]) or on the groin ([[tinea cruris]]). It is transmitted even by sharing footwear. | *The various parasitic fungi that cause athlete's foot can also cause skin infections on other areas of the body, most often under [[toenail]]s ([[onychomycosis]]) or on the [[groin]] ([[tinea cruris]]). | ||
*It is transmitted even by sharing footwear. | |||
===Pathology=== | ===Pathology=== | ||
*Majority of the cases of athlete's foot are caused by ''Trichophyton rubrum''. But other organisms such as ''Epidermophyton floccosum'', ''Trichophyton interdigitale'', ''Trichophyton mentagrophytes'' are also implicated in development of tinea pedis. | *Majority of the cases of athlete's foot are caused by ''[[Trichophyton rubrum]]''. But other organisms such as ''Epidermophyton floccosum'', ''[[Trichophyton interdigitale]]'', ''[[Trichophyton mentagrophytes and trichophyton rubrum|Trichophyton mentagrophytes]]'' are also implicated in development of tinea pedis. | ||
*''Trichophyton tonsurans'' has been identified as a cause of tinea pedis infections in children. <ref name="pmid25736317">{{cite journal| author=Hiruma J, Ogawa Y, Hiruma M| title=Trichophyton tonsurans infection in Japan: epidemiology, clinical features, diagnosis and infection control. | journal=J Dermatol | year= 2015 | volume= 42 | issue= 3 | pages= 245-9 | pmid=25736317 | doi=10.1111/1346-8138.12678 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25736317 }} </ref> | *''[[Trichophyton tonsurans]]'' has been identified as a cause of tinea pedis infections in [[Child|children]]. <ref name="pmid25736317">{{cite journal| author=Hiruma J, Ogawa Y, Hiruma M| title=Trichophyton tonsurans infection in Japan: epidemiology, clinical features, diagnosis and infection control. | journal=J Dermatol | year= 2015 | volume= 42 | issue= 3 | pages= 245-9 | pmid=25736317 | doi=10.1111/1346-8138.12678 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25736317 }} </ref> | ||
* The fungi cause breakdown of superficial skin through secretion of | * The fungi cause breakdown of superficial skin through secretion of [[enzyme]]<nowiki/>s called keratinases which dissolve [[keratin]].<ref name="pmid27291045">{{cite journal| author=Sharifzadeh A, Shokri H, Khosravi AR| title=In vitro evaluation of antifungal susceptibility and keratinase, elastase, lipase and DNase activities of different dermatophyte species isolated from clinical specimens in Iran. | journal=Mycoses | year= 2016 | volume= 59 | issue= 11 | pages= 710-719 | pmid=27291045 | doi=10.1111/myc.12521 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=27291045 }} </ref> | ||
*The fungal cell wall of dermatophytes also contain mannans which diminish the body's inflammatory response by decreasing antigen presenting and processing.<ref name="pmid7621400">{{cite journal| author=Weitzman I, Summerbell RC| title=The dermatophytes. | journal=Clin Microbiol Rev | year= 1995 | volume= 8 | issue= 2 | pages= 240-59 | pmid=7621400 | doi= | pmc=172857 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=7621400 }} </ref> | *The fungal [[cell wall]] of dermatophytes also contain mannans which diminish the body's [[inflammatory response]] by decreasing [[Antigen-presenting cell|antigen presenting]] and processing.<ref name="pmid7621400">{{cite journal| author=Weitzman I, Summerbell RC| title=The dermatophytes. | journal=Clin Microbiol Rev | year= 1995 | volume= 8 | issue= 2 | pages= 240-59 | pmid=7621400 | doi= | pmc=172857 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=7621400 }} </ref> | ||
*It is interesting to note that''Trichophyton rubrum'' often causes chronic and long drawn infection due to increased production of mannans which decrease the turnover and proliferation of keratinocytes.<ref name="pmid8060745">{{cite journal| author=Dahl MV, Grando SA| title=Chronic dermatophytosis: what is special about Trichophyton rubrum? | journal=Adv Dermatol | year= 1994 | volume= 9 | issue= | pages= 97-109; discussion 110-1 | pmid=8060745 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8060745 }} </ref> | *It is interesting to note that [[Trichophyton rubrum|''Trichophyton rubrum'']] often causes chronic and long drawn infection due to increased production of mannans which decrease the turnover and proliferation of [[Keratinocyte|keratinocytes]].<ref name="pmid8060745">{{cite journal| author=Dahl MV, Grando SA| title=Chronic dermatophytosis: what is special about Trichophyton rubrum? | journal=Adv Dermatol | year= 1994 | volume= 9 | issue= | pages= 97-109; discussion 110-1 | pmid=8060745 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=8060745 }} </ref> | ||
* The dermatophytes thrive in a moist and damp environment. Maceration, superficial tears in the skin and chronic occlusive footwear usage for long periods of time increase the chance of getting infected. | * The dermatophytes thrive in a moist and damp environment. [[Maceration]], superficial tears in the skin and chronic occlusive footwear usage for long periods of time increase the chance of getting infected. | ||
* Several innate factors such as transferrin, beta globulins and sebum have a growth-inhibitory effect on these fungi. Transferrin, particularly the unsaturated form inhibits growth by binding iron which is required for growth and propagation of dermatophytes. <ref name="pmid1151148">{{cite journal| author=King RD, Khan HA, Foye JC, Greenberg JH, Jones HE| title=Transferrin, iron, and dermatophytes. I. Serum dematophyte inhibitory component definitively identified as unsaturated transferrin. | journal=J Lab Clin Med | year= 1975 | volume= 86 | issue= 2 | pages= 204-12 | pmid=1151148 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1151148 }} </ref> | * Several innate factors such as [[transferrin]], [[beta globulins]] and [[sebum]] have a growth-inhibitory effect on these fungi. Transferrin, particularly the unsaturated form inhibits growth by binding [[iron]] which is required for growth and propagation of dermatophytes. <ref name="pmid1151148">{{cite journal| author=King RD, Khan HA, Foye JC, Greenberg JH, Jones HE| title=Transferrin, iron, and dermatophytes. I. Serum dematophyte inhibitory component definitively identified as unsaturated transferrin. | journal=J Lab Clin Med | year= 1975 | volume= 86 | issue= 2 | pages= 204-12 | pmid=1151148 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1151148 }} </ref> | ||
* A poor immune system such as in immunocompromised individuals also is a predilection for infection with tinea spp.<ref name="pmid30894136">{{cite journal| author=Dai Y, Xia X, Shen H| title=Multiple abscesses in the lower extremities caused by Trichophyton rubrum. | journal=BMC Infect Dis | year= 2019 | volume= 19 | issue= 1 | pages= 271 | pmid=30894136 | doi=10.1186/s12879-019-3897-3 | pmc=6425592 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=30894136 }} </ref> | * A poor [[immune system]] such as in [[immunocompromised]] individuals also is a predilection for infection with tinea spp.<ref name="pmid30894136">{{cite journal| author=Dai Y, Xia X, Shen H| title=Multiple abscesses in the lower extremities caused by Trichophyton rubrum. | journal=BMC Infect Dis | year= 2019 | volume= 19 | issue= 1 | pages= 271 | pmid=30894136 | doi=10.1186/s12879-019-3897-3 | pmc=6425592 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=30894136 }} </ref> | ||
===Histopathology of Tinea pedis=== | ===Histopathology of Tinea pedis=== | ||
Scrapings of skin affected with tinea pedis prepared with KOH show the following features. | Scrapings of skin affected with tinea pedis prepared with KOH show the following features. | ||
*Hyperkeratosis | *[[Hyperkeratosis]] | ||
*Acanthosis | *[[Acanthosis nigricans|Acanthosis]] | ||
*Perivascular infiltrate | *Perivascular infiltrate | ||
Latest revision as of 18:17, 27 July 2020
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2] Associate Editor(s)-in-Chief: Sanjana Nethagani, M.B.B.S.[3]
Overview
- Athlete's foot is caused by a parasitic fungus and is a communicable disease.[1]
- It is typically transmitted in moist environments where people walk barefoot, such as showers, bath houses, and locker rooms.[2][3][1]
- It can also be transmitted by sharing footwear with an infected person, or less commonly, by sharing towels with an infected person.
Pathophysiology
Transmission
- The various parasitic fungi that cause athlete's foot can also cause skin infections on other areas of the body, most often under toenails (onychomycosis) or on the groin (tinea cruris).
- It is transmitted even by sharing footwear.
Pathology
- Majority of the cases of athlete's foot are caused by Trichophyton rubrum. But other organisms such as Epidermophyton floccosum, Trichophyton interdigitale, Trichophyton mentagrophytes are also implicated in development of tinea pedis.
- Trichophyton tonsurans has been identified as a cause of tinea pedis infections in children. [4]
- The fungi cause breakdown of superficial skin through secretion of enzymes called keratinases which dissolve keratin.[5]
- The fungal cell wall of dermatophytes also contain mannans which diminish the body's inflammatory response by decreasing antigen presenting and processing.[6]
- It is interesting to note that Trichophyton rubrum often causes chronic and long drawn infection due to increased production of mannans which decrease the turnover and proliferation of keratinocytes.[7]
- The dermatophytes thrive in a moist and damp environment. Maceration, superficial tears in the skin and chronic occlusive footwear usage for long periods of time increase the chance of getting infected.
- Several innate factors such as transferrin, beta globulins and sebum have a growth-inhibitory effect on these fungi. Transferrin, particularly the unsaturated form inhibits growth by binding iron which is required for growth and propagation of dermatophytes. [8]
- A poor immune system such as in immunocompromised individuals also is a predilection for infection with tinea spp.[9]
Histopathology of Tinea pedis
Scrapings of skin affected with tinea pedis prepared with KOH show the following features.
- Hyperkeratosis
- Acanthosis
- Perivascular infiltrate
References
- ↑ 1.0 1.1 Causes of athlete's foot, at WebMD
- ↑ "Athlete's foot". Mayo Clinic Health Center.
- ↑ [1]
- Risk factors for athlete's foot, atWebMD
- ↑ Hiruma J, Ogawa Y, Hiruma M (2015). "Trichophyton tonsurans infection in Japan: epidemiology, clinical features, diagnosis and infection control". J Dermatol. 42 (3): 245–9. doi:10.1111/1346-8138.12678. PMID 25736317.
- ↑ Sharifzadeh A, Shokri H, Khosravi AR (2016). "In vitro evaluation of antifungal susceptibility and keratinase, elastase, lipase and DNase activities of different dermatophyte species isolated from clinical specimens in Iran". Mycoses. 59 (11): 710–719. doi:10.1111/myc.12521. PMID 27291045.
- ↑ Weitzman I, Summerbell RC (1995). "The dermatophytes". Clin Microbiol Rev. 8 (2): 240–59. PMC 172857. PMID 7621400.
- ↑ Dahl MV, Grando SA (1994). "Chronic dermatophytosis: what is special about Trichophyton rubrum?". Adv Dermatol. 9: 97–109, discussion 110-1. PMID 8060745.
- ↑ King RD, Khan HA, Foye JC, Greenberg JH, Jones HE (1975). "Transferrin, iron, and dermatophytes. I. Serum dematophyte inhibitory component definitively identified as unsaturated transferrin". J Lab Clin Med. 86 (2): 204–12. PMID 1151148.
- ↑ Dai Y, Xia X, Shen H (2019). "Multiple abscesses in the lower extremities caused by Trichophyton rubrum". BMC Infect Dis. 19 (1): 271. doi:10.1186/s12879-019-3897-3. PMC 6425592. PMID 30894136.