This document summarizes various fungal skin infections (dermatophytoses) caused by dermatophytes. It describes the causative fungi of superficial mycoses and outlines the clinical presentation of common dermatophytoses including tinea corporis, tinea cruris, tinea pedis, tinea manuum, tinea capitis and others. It also provides details on laboratory identification of dermatophytes through microscopic examination and fungal culture characteristics. Key identifying features of common dermatophyte genera like Trichophyton, Microsporum, and Epidermophyton are highlighted.

1. Superficial MycosesCausative agents:MalasseziafurfurExophialawerneckiiTrichosporonbeigeliiPiedraiahortae

2. Cutaneous mycoses (Dermatophytoses)fungal infections involving the dermis and its appendages (hair follicles and nails)

3. Dermatomycosis - more general name for any skin disease caused by a fungus.

4. Dermatophytosis – mycotic infection of the nails, hair, and/or stratum corneum of the skin caused by dermatophytes.

5. Generally called “Ringworms” or

6. “Tineas” (Latin for ringworms)DermatophytosesDermatophytes are keratinophilicAll produce septate, hyaline hyphaeInfection:Colonization of the skinSpreads in a centrifugal pattern forming a ringAffected area varies from patchy scaling to a toxic eczema-like reaction

7. DermatophytosesSeverity depends on (1) strains or species of fungus involved (2) sensitivity of the host to a particular pathogenic fungus. More severe reactions occur when a dermatophyte crosses non-host lines.

8. Major sources of ringworm infectionSchools, military camps, prisons. Warm damp areas (e.g., tropics, moisture accumulation in clothing and shoes). Animals (e.g., dogs, cats, cattle, poultry, etc.).

9. DermatophytesGeophilic species - e.g., M. gypseum, T. ajelloiZoophilic species - e.g., M. canis, T. verrucosumAnthropophilic species - e.g., M. audounii, T. tonsurans)

10. a. Microsporum - skin, hair (scalp) - children, rarely in adults - spontaneous remissionb. Epidermophyton - skin, nailsc. Trichophyton - hair (scalp), skin & nails - chronic

11. TineasSkin:Tinea corporis Tinea crurisTinea manuum Tinea pedisTinea fascie Tinea imbricataHairy areas:Tinea capitis Tinea barbaeNail:Tineaunguium/ onychomycosis

12. Tinea corporisRingworm of the body (Generally restricted to stratum corneum of the smooth skin)Reddened, circular scaly patch with sharp delineated margins (may developing vesicles and postules)EA: Trichophyton rubrumTrichophytonmentagrophytes

13. Tinea corporis

14. Tinea corporis – body ringworm

15. Tinea corporisMOT: direct contact; fomites; autoinnoculationnormally resolves itself in several months. (T. rubrum – relapse)TX: topical agent containing tolnaftate, ketoconazole, miconazole.

16. Tinea corporisvigorous 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. Widespread tinea corporis and more severe lesions: systemic griseofulvin treatment (about 6 weeks for effective treatment).

17. Tinea imbricata

18. Tinea crurisRingworm of the groin Almost exclusively in men Lesion resemble tinea corporisOften starts on the scrotum and spread to the groin as dry, itchy lesions

19. Tinea cruris(“jock itch”)

20. Tinea crurisEA: Trichophyton rubrum Epidermophyton floccosum(usually associated with epidemics) MOT: Sharing of linens, towels or clothes (Athletes, soldiers, ship crews)Predisposing factors: persistent perspiration, irritation of skin from clothes, or other pre-existing diseases.

21. Tinea crurisDiagnosis KOH and Culture of dermatophyte from skin scrapings. If lesion "weep", it is likely caused by a yeast, such as, Candida albicansTreatment TolnaftateArea is sensitive

22. Tinea pedisRingworm of the soles and interdigital areasmen & women are equally affectedMore common in adultsPeeling, maceration and fissuring of the skin to fluid-filled vesicles and bullae.

23. Tinea pedis

24. Tinea Pedis – Athlete’s Foot Infection

25. Tinea pedisAll forms are pruriticEA: T. rubrum(chronic infections) E. floccosum(acute & spontaneously resolves)

26. Tinea manuumRingworm of the palms and interdigitsCommon among patients with tinea pedisSymptoms generally resemble that of tinea pedisEA: T. rubrum & T. mentagrophytes E. floccosum

27. Tinea manunm

28. Dermatophytid Reaction

29. Tinea barbaeRingworm of the bearded areas of the neck postularfolliculitisCommon among men who work with cattlesEA: T. verrucosum & T. mentagrophytes

30. Tinea barbaeKerions: boggy inflammation/spongy swelling Alopecia is also common in untreated infections

31. Tinea barbae

32. Tinea fascie

33. Two forms of T. unguium:Leukonychiamycotica /superficial white onychomycosis - invasion of fungus restricted on patches or pits on surface of the toenail. Invasive subungualdermatophytosis- lateral or distal edges first involved, followed by invasion of nail plates by dermatophytes. Tinea unguium

34. Tinea unguiumMost commonly caused by T. rubrum, then E. floccosumor otherTrichophyton spp. Resistant to treatment Rarely resolves spontaneously.

35. Tinea unguium

36. Tinea Unguium

37. Tinea capitisRingworm of the scalp, eyebrows and eyelashes Fungus grows into hair follicle and hair shaft Caused by species of Microsporumand Trichophyton.

38. Tinea capitisWood's lampSubculture any strands of hair that fluoresce

39. Tinea capitis

40. Tinea capitisEctothrix infection - fragmentation of mycelium into conidia around the hair shaft or just beneath the cuticle.

41. Tinea capitisCaused by M. audouinii, M. canis, M. ferrugineum, T. mentagrophytes, T. verrucosum and T. megninii.

42. Tinea capitis“gray patch T. capitis" ectothrix disease common in children usually not associated with inflammation.

43. Tinea capitisEndothrix infection - arthroconidia formation within the hair shaft. caused by T. tonsurans, T. violaceum, T. rubrum, and T. gourvillii. Tinea capitis“Black-dot T. capitis” Formed as the hair continues to grow, as the conidia in the shafts of the hair appear as black dotsTinea Capitis

44. Tinea favosa (favus)ringworm infection of the scalp (crusty hair) Characterized by the occurrence of dense masses of mycelium and epithelial debris, which forms yellowish, cup-shaped crusts.

45. Tinea favosa (favus)Leads to scarring and alopecia“mousy odor”Caused by T. schoenleinii

46. Diagnosis of DermatophytosesNote the symptoms. Note the kind of tissue attacked Observe proper collection of the specimenKeep specimen dry during transport Microscopic examination of slides of skin scrapings, nail scrapings, and hair.

47. Methods:1. Direct MicroscopyNot sensitiveUseful in more severe conditionsKOH (10% & 20%)

48. 2. CultureObserve type of coloniesPigment production: one pigment on the surface of the colony, and another pigment other than black, on the reverse

49. Emmon’s modification of SabouraudDextrose Agar (SDA); orSDA with 4% glucoseincorporate chloramphenicol or gentamicin and cycloheximidethiamine will enhance growth of dermatophytes esp. Trichophytonverrucosum (Nutritional Studies)Dermatophyte Test medium (DTM) screening medium (w/ phenol red)

50. Microsporum speciesMicrosporumgypseumMicrosporumcanis

51. Microsporum speciesCommon features:Colony:Mycelium: white to buffUnderside: yellow to reddish brown

52. MicrosporumgypseumColonies are at first white and downy, later become flat and granular with white sterile hyphae at the centerSurface pigment is tan to cinnamon –pink to brownReverse is tan to orange-brown or modified cinnamon-pink on PDA

54. MicrosporumgypseumMacronidia: Ellipsoidal to fusiform with thick, rough wallsMicroconidia: Sessile and solitaryWood’s lamp: Dull-green yellow

55. Microsporum canisMacroconidia: Spindle shaped with asymmetrical beaked apex and thick rough wallsMicroconidia: Clavate or pyriform

56. MicrosporumcanisTeleomorph: ArthrodermaotaeWood’s lamp: Bright yellow-green

57. Colonies: Yellow pigment on reverse

58. Epidermophyton speciesEpidermophyton floccosumTineaunguium, tineacruris, pedisEpidermophyton floccosumColony:Center of colony may be foldedMycelium: mustard yellow or “khaki”; suede, gentle folds; slow growerUnderside: yellow-brown or yellow orange

59. Epidermophyton floccosumMicroscopic:attached in multiples (2 – 4/group)Macroconidia = moderately thick , smooth walls (beaver tails) or paddle-likeClubbed-shaped, 2 – 5 cell macroconidiaSeptate,hyalinehyphae

60. Epidermophyton floccosumMicroscopic:

61. Trichophyton speciesPresence of macroconidia in cultures varies and may not help in identification of cultures. Most common species include: Trichophyton mentagrophytesT. rubrumT. tonsuransT. verrucosumT. violaceumT. schoenleiniiT. ajelloi(rare infects humans).

62. TrichophytonmentagrophytesMost common dermatophyte on humans and animals. Microconidia: en grappe

63. Macroconidia: when present, are cigar- shaped. Spiral hyphaeTrichophytonmentagrophytes

64. Colony: Texture: deep, cottony; white and downy; pale yellow to tan reverseTrichophytonmentagrophytes

65. Trichophytonmentagrophytes

66. TrichophytonrubrumResistant and persistent Microconidium: clavate or "teardrop" shape with a broad attachment point of the hyphae. may develop on sides of macroconidium. Trichophytonrubrum

67. Colony: fluffy white with Port burgundy wine or venous blood underside. When intensely pigmented in culture the color is reminiscent Trichophytonrubrum

69. TrichophytontonsuransAnthropophilic; third most common cause of tinea capitisMacroconidia: Short blunt , irregular clubs with moderately thick, smooth wallsMicroconidia: Truncate of varying shapes; typically numerousHyphae are hyaline, septate and often with terminal swellings

71. TrichophytontonsuransColony: Usually flat and off-white to yellow initially with a powdery texture; wrinkledReverse on SDA is yellow-brown to reddish brownGrowth is enhanced by thiamine and inositol.

73. TrichophytonverrucosumAssociated with cattle ("barn itch") Causes severe infections in humans on the scalp and beard.

74. TrichophytonverrucosumColony: no pigment to yellow on reverse. On unenriched media chains of chlamydoconidia and antler-like hyphae. On thiamine-enriched media, produces many small microconidia and occasionally macroconidiaTrichophyton verrucosumhttp://www.mycology.adelaide.edu.au/Fungal_Descriptions/Dermatophytes/Trichophyton/verrucosum.html

75. TrichophytonschoenleiniiEndothrix infection of hair.

76. TrichophytonschoenleiniiColony: waxy to suede-like; off white in color. Colony may become convoluted from folds that develop No conidia (micro- or macro-) even on enriched media .