6 cutaneus myco


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  • Dermatophytes ("skin plants“). Tinea: char. by advancing , serpiginous nature of the lesion
  • dermatophyte crosses non-host lines (e.g., from an animal species to man).Dermatophytes are NOT inhibited by CYCLOHEXIMIDE
  • Evolutionary transition from a saprophytic to a parasitic lifestyle. Some have strict association with….Geophilic species – “earth-loving” (e.g., M. gypseum, T. ajelloi)Zoophilic species - keratin-utilizing on living animal host (e.g., M. canis, T. verrucosum)Anthropophilic species -  keratin-utilizing on humans hosts (e.g., M. audounii, T. tonsurans)
  • Microsporum -skin, hair (scalp), rarely nails Epidermophyton - adults, rarely childrenTrichophyton - both children & adults - chronic
  • Tinea unguium (onychomycosis) Tineas or “ringworms”
  • Fomites: rugs and carpets (fomites). T.metagrophytes (w/ red pigment (colony); urease production in 3 - 5 days; V-shape penetration on hair-baiting test)T. rubrum (intense red pigment is more enhanced by culture on PFA or CMA w/ 1% DEXTROSE; no urease; grows outside hair shaft w/o penetration.)
  • Fomites: rugs and carpets (fomites). T.metagrophytes (w/ red pigment (colony); urease production in 3 - 5 days; V-shape penetration on hair-baiting test)T. rubrum (intense red pigment is more enhanced by culture on PFA or CMA w/ 1% DEXTROSE; no urease; grows outside hair shaft w/o penetration.)
  • Tinea imbricata -subtype of Tinea corporis, concentric layers of lesions
  • Ringworm of the groin (“jock itch”) Infection seen on scrotum and inner thigh, the penis is usually not infected.
  • Epidermophyton floccosum(usually associated with epidemics because resistant arthroconidia in skin scales can survive for years on rugs, shower stalls, locker room floors *Predisposing factors: persistent perspiration, high humidity, irritation of skin from clothes, such as tight fitting underwear or athletic supporters or other pre-existing diseases, such as diabetes and obesity.
  • Diagnosis If lesion "weep", it is likely caused by a yeast, such as,  Candida albicans, and not by a  dermatophyte, especially if infections are seen in a woman.
  • “Athlete’s foot”
  • “barber’s itch” – Tinea barbae
  • “barber’s itch” – Tinea barbaeKerions: boggy inflammation- due to deep infection of hair follicles
  • KOH (10% & 20%)May be added with DMSO(to increase penetration of stain into tissues)
  • DTM: contains phenol red (dermatophytes produce alkaline metabolites resulting to change in the color from yellow to reddish- orange or red)
  • Macronidia: Ellipsoidal to fussiform (cucumber shape) with thick, rough walls
  • Epidermophytonfloccosum:Only one pathogenic specie in this genus.
  • 6 cutaneus myco

    1. 1. Superficial Mycoses<br />Causative agents:<br />Malasseziafurfur<br />Exophialawerneckii<br />Trichosporonbeigelii<br />Piedraiahortae<br />
    2. 2. Cutaneous mycoses (Dermatophytoses)<br />fungal infections involving the dermis and its appendages<br /> (hair follicles and nails)<br />
    3. 3. <ul><li>Dermatomycosis  - more general name for any skin disease caused by a fungus.
    4. 4. Dermatophytosis – mycotic infection of the nails, hair, and/or stratum corneum of the skin caused by dermatophytes.
    5. 5. Generally called “Ringworms” or
    6. 6. “Tineas” (Latin for ringworms)</li></li></ul><li>Dermatophytoses<br />Dermatophytes are keratinophilic<br />All produce septate, hyaline hyphae<br />Infection:<br />Colonization of the skin<br />Spreads in a centrifugal pattern forming a ring<br />Affected area varies from patchy scaling to a toxic eczema-like reaction<br />
    7. 7. Dermatophytoses<br />Severity depends on <br /> (1) strains or species of fungus involved (2) sensitivity of the host to a particular pathogenic fungus.  <br />More severe reactions occur when a dermatophyte crosses non-host lines.<br />
    8. 8. Major sources of ringworm infection<br />Schools, military camps, prisons. <br />Warm damp areas (e.g., tropics, moisture accumulation in clothing and shoes). <br />Animals (e.g., dogs, cats, cattle, poultry, etc.). <br />
    9. 9. Dermatophytes<br />Geophilic species - e.g., M. gypseum, <br /> T. ajelloi<br />Zoophilic species - e.g., M. canis, T. verrucosum<br />Anthropophilic species -  e.g., M. audounii, T. tonsurans) <br />
    10. 10. a. Microsporum<br /> - skin, hair (scalp) <br /> - children, rarely in adults<br /> - spontaneous remission<br />b. Epidermophyton<br /> - skin, nails<br />c. Trichophyton<br /> - hair (scalp), skin & nails<br /> - chronic<br />
    11. 11. Tineas<br />Skin:<br />Tinea corporis Tinea cruris<br />Tinea manuum Tinea pedis<br />Tinea fascie Tinea imbricata<br />Hairy areas:<br />Tinea capitis Tinea barbae<br />Nail:<br />Tineaunguium/ onychomycosis<br />
    12. 12. Tinea corporis<br />Ringworm of the body (Generally restricted to stratum corneum of the smooth skin)<br />Reddened, circular scaly patch with sharp delineated margins (may developing vesicles and postules)<br />EA: Trichophyton rubrum<br />Trichophytonmentagrophytes<br />
    13. 13. Tinea corporis<br />
    14. 14. Tinea corporis – body ringworm<br />
    15. 15. Tinea corporis<br />MOT: direct contact; fomites; autoinnoculation<br />normally resolves itself in several months. (T. rubrum – relapse)<br />TX: topical agent containing tolnaftate, ketoconazole, miconazole. <br />
    16. 16. Tinea corporis<br />vigorous treatment including cleaning of area to remove scales and fungicidal topical applications of ammoniated mercury ointment, 3 % salicylic and sulfuric acid, or tincture of iodine for several weeks. <br />Widespread tinea corporis and more severe lesions: systemic griseofulvin treatment (about 6 weeks for effective treatment). <br />
    17. 17. Tinea imbricata<br />
    18. 18. Tinea cruris<br />Ringworm of the groin <br />Almost exclusively in men <br />Lesion resemble tinea corporis<br />Often starts on the scrotum and spread to the groin as dry, itchy lesions<br />
    19. 19. Tinea cruris(“jock itch”)<br />
    20. 20. Tinea cruris<br />EA: Trichophyton rubrum<br /> Epidermophyton floccosum(usually associated with epidemics)<br /> MOT: Sharing of linens, towels or clothes (Athletes, soldiers, ship crews)<br />Predisposing factors: persistent perspiration, irritation of skin from clothes, or other pre-existing diseases. <br />
    21. 21. Tinea cruris<br />Diagnosis <br />KOH and Culture of dermatophyte from skin scrapings. <br />If lesion "weep", it is likely caused by a yeast, such as,  Candida albicans<br />Treatment <br />Tolnaftate<br />Area is sensitive<br />
    22. 22. Tinea pedis<br />Ringworm of the soles and interdigital areas<br />men & women are equally affected<br />More common in adults<br />Peeling, maceration and fissuring of the skin to fluid-filled vesicles and bullae.<br />
    23. 23. Tinea pedis<br />
    24. 24. Tinea Pedis – Athlete’s Foot Infection<br />
    25. 25. Tinea pedis<br />All forms are pruritic<br />EA: T. rubrum(chronic infections)<br /> E. floccosum(acute & spontaneously resolves)<br />
    26. 26. Tinea manuum<br />Ringworm of the palms and interdigits<br />Common among patients with tinea pedis<br />Symptoms generally resemble that of tinea pedis<br />EA: T. rubrum & T. mentagrophytes<br /> E. floccosum<br />
    27. 27. Tinea manunm<br />
    28. 28. Dermatophytid Reaction<br />
    29. 29. Tinea barbae<br />Ringworm of the bearded areas of the neck <br />postularfolliculitis<br />Common among men who work with cattles<br />EA: T. verrucosum & <br /> T. mentagrophytes<br />
    30. 30. Tinea barbae<br />Kerions: boggy inflammation/spongy swelling <br />Alopecia is also common in untreated infections<br />
    31. 31. Tinea barbae<br />
    32. 32. Tinea fascie<br />
    33. 33. Two forms of T. unguium:<br />Leukonychiamycotica /superficial white onychomycosis - invasion of fungus restricted on patches or pits on surface of the toenail. <br />Invasive subungualdermatophytosis- lateral or distal edges first involved, followed by invasion of nail plates by dermatophytes. <br />Tinea unguium<br />
    34. 34. Tinea unguium<br />Most commonly caused by T. rubrum, then E. floccosumor otherTrichophyton spp. <br />Resistant to treatment <br />Rarely resolves spontaneously. <br />
    35. 35. Tinea unguium<br />
    36. 36. Tinea Unguium<br />
    37. 37. Tinea capitis<br />Ringworm of the scalp, eyebrows and eyelashes <br />Fungus grows into hair follicle and hair shaft <br />Caused by species of Microsporumand Trichophyton. <br />
    38. 38. Tinea capitis<br />Wood's lamp<br />Subculture any strands of hair that fluoresce<br />
    39. 39. Tinea capitis<br />
    40. 40. Tinea capitis<br />Ectothrix infection - fragmentation of mycelium into conidia around the hair shaft or just beneath the cuticle.<br />
    41. 41. Tinea capitis<br />Caused by M. audouinii, M. canis, M. ferrugineum, T. mentagrophytes, T. verrucosum and T. megninii. <br />
    42. 42. Tinea capitis<br />“gray patch T. capitis" <br />ectothrix disease common in children usually not associated with inflammation. <br />
    43. 43. Tinea capitis<br />Endothrix infection - arthroconidia formation within the hair shaft.  <br /><ul><li>caused by T. tonsurans, T. violaceum, T. rubrum, and T. gourvillii. </li></li></ul><li>Tinea capitis<br />“Black-dot T. capitis” <br /><ul><li>Formed as the hair continues to grow, as the conidia in the shafts of the hair appear as black dots</li></li></ul><li>Tinea Capitis<br />
    44. 44. Tinea favosa (favus)<br />ringworm infection of the scalp (crusty hair) <br />Characterized by the occurrence of dense masses of mycelium and epithelial debris, which forms yellowish, cup-shaped crusts.<br />
    45. 45. Tinea favosa (favus)<br />Leads to scarring and alopecia<br />“mousy odor”<br />Caused by T. schoenleinii<br />
    46. 46. Diagnosis of Dermatophytoses<br />Note the symptoms. <br />Note the kind of tissue attacked <br />Observe proper collection of the specimen<br />Keep specimen dry during transport <br />Microscopic examination of slides of skin scrapings, nail scrapings, and hair.  <br />
    47. 47. Methods:<br />1. Direct Microscopy<br />Not sensitive<br />Useful in more severe conditions<br />KOH (10% & 20%)<br />
    48. 48. 2. Culture<br />Observe type of colonies<br />Pigment production: one pigment on the surface of the colony, and another pigment other than black, on the reverse<br />
    49. 49. Emmon’s modification of SabouraudDextrose Agar (SDA); orSDA with 4% glucose<br />incorporate chloramphenicol or gentamicin and cycloheximide<br />thiamine will enhance growth of dermatophytes esp. Trichophytonverrucosum (Nutritional Studies)<br />Dermatophyte Test medium (DTM)<br /> screening medium (w/ phenol red)<br />
    50. 50. Microsporum species<br />Microsporumgypseum<br />Microsporumcanis<br />
    51. 51. Microsporum species<br />Common features:<br />Colony:<br />Mycelium: white to buff<br />Underside: yellow to reddish brown<br />
    52. 52. Microsporumgypseum<br />Colonies are at first white and downy, later become flat and granular with white sterile hyphae at the center<br />Surface pigment is tan to cinnamon –pink to brown<br />Reverse is tan to orange-brown or modified cinnamon-pink on PDA<br />
    53. 53.
    54. 54. Microsporumgypseum<br />Macronidia: Ellipsoidal to fusiform with thick, rough walls<br />Microconidia: Sessile and solitary<br />Wood’s lamp: Dull-green yellow <br />
    55. 55. Microsporum canis<br />Macroconidia: Spindle shaped with asymmetrical beaked apex and thick rough walls<br />Microconidia: Clavate or pyriform<br />
    56. 56. MicrosporumcanisTeleomorph: Arthrodermaotae<br /><ul><li>Wood’s lamp: Bright yellow-green
    57. 57. Colonies: Yellow pigment on reverse </li></li></ul><li>
    58. 58. Epidermophyton species<br />Epidermophyton floccosum<br /><ul><li>Tineaunguium, tineacruris, pedis</li></li></ul><li>Epidermophyton floccosum<br />Colony:<br />Center of colony may be folded<br />Mycelium: mustard yellow or “khaki”; suede, gentle folds; slow grower<br />Underside: yellow-brown or yellow orange<br />
    59. 59. Epidermophyton floccosum<br />Microscopic:<br />attached in multiples (2 – 4/group)<br />Macroconidia = moderately thick , smooth walls (beaver tails) or paddle-like<br />Clubbed-shaped, 2 – 5 cell macroconidia<br />Septate,hyalinehyphae<br />
    60. 60. Epidermophyton floccosum<br />Microscopic:<br />
    61. 61. Trichophyton species<br />Presence of macroconidia in cultures varies and may not help in identification of cultures. <br />Most common species include: <br />Trichophyton mentagrophytes<br />T. rubrum<br />T. tonsurans<br />T. verrucosum<br />T. violaceum<br />T. schoenleinii<br />T. ajelloi(rare infects humans). <br />
    62. 62. Trichophytonmentagrophytes<br />Most common dermatophyte on humans and animals. <br />Microconidia: en grappe<br />
    63. 63. Macroconidia: when present, are cigar- shaped. <br />Spiral hyphae<br />Trichophytonmentagrophytes<br />
    64. 64. Colony: Texture: deep, cottony; white and downy; pale yellow to tan reverse<br />Trichophytonmentagrophytes<br />
    65. 65. Trichophytonmentagrophytes<br />
    66. 66. Trichophytonrubrum<br />Resistant and persistent <br />Microconidium: clavate or "teardrop" shape with a broad attachment point of the hyphae.<br /><ul><li> may develop on sides of macroconidium. </li></li></ul><li>Trichophytonrubrum<br />
    67. 67. Colony: fluffy white with Port burgundy wine or venous blood underside. When intensely pigmented in culture the color is reminiscent <br />Trichophytonrubrum<br />
    68. 68.
    69. 69. Trichophytontonsurans<br />Anthropophilic; third most common cause of tinea capitis<br />Macroconidia: Short blunt , irregular clubs with moderately thick, smooth walls<br />Microconidia: Truncate of varying shapes; typically numerous<br />Hyphae are hyaline, septate and often with terminal swellings<br />
    70. 70.
    71. 71. Trichophytontonsurans<br />Colony: Usually flat and off-white to yellow initially with a powdery texture; wrinkled<br />Reverse on SDA is yellow-brown to reddish brown<br />Growth is enhanced by thiamine and inositol.<br />
    72. 72.
    73. 73. Trichophytonverrucosum<br />Associated with cattle ("barn itch") <br />Causes severe infections in humans on the scalp and beard. <br />
    74. 74. Trichophytonverrucosum<br />Colony: no pigment to yellow on reverse. <br />On unenriched media <br /><ul><li>chains of chlamydoconidia and antler-like hyphae. </li></ul>On thiamine-enriched media, <br /><ul><li> produces many small microconidia and occasionally macroconidia</li></li></ul><li>Trichophyton verrucosum<br />http://www.mycology.adelaide.edu.au/Fungal_Descriptions/Dermatophytes/Trichophyton/verrucosum.html<br />
    75. 75. Trichophytonschoenleinii<br />Endothrix infection of hair. <br />
    76. 76. Trichophytonschoenleinii<br />Colony: waxy to suede-like; off white in color. <br /><ul><li>Colony may become convoluted from folds that develop </li></ul>No conidia (micro- or macro-) even on enriched media . <br />