Fungal Infections of Skin, Soft tissue.pptx

Fungal infections of skin

1. Fungal Infections of Skin

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3. Introduction Affect: skin, nail & hair Mild & chronic infections Fungi specialized saprophytes: digest keratin Three types of infections: Surface infection: dead layer of skin- tinea Cutaneous infection: cornified layer of skin, dermatophytes Subcutaneous infections- mycetoma, rhinosporidiosis 3

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5. Surface infection Dead layer of skin No inflammatory response Cosmetic effects Eg. Tinea versicolor, Tinea nigra & Piedra. Cutaneous infection: Dermatophytosis/ tinea/ ringworm cornified layer of skin, hair, nail Inflammatory & allergic response Candidiasis 5

6. Tinea Versicolor 6 Tinea versicolor (or pityriasis versicolor) – chronic recurrent condition involving the superficial layer (stratum corneum ) of skin. Caused by a lipophilic fungus Malassezia furfur.

7. Clinical Manifestations 7 Characterized by flat-round scaly patches of hypo- to hyperpigmentation of skin. Lesions - non-inflammatory and non-pruritic Areas rich in sebaceous glands - commonly involved - neck, chest, or upper arms Disease is more common in moist humid areas.

8. TINEA NIGRA Localized infection of stratum corneum Painless brown or black macular lesions- hands Causative agent: Hortaea wernickii ( Exophiala werneckii ), black coloured fungus

9. PIEDRA Infection of hair Characterized by firm, irregular nodules along the hair shaft Black piedra – Piedraia hortae White piedra – Trichosporon beigelii

10. Laboratory Diagnosis 10 Direct microscopy: Skin scrapings examined - after treating with 10% KOH. Mixture of budding yeasts and short septate hyphae – seen - spaghetti and meatballs appearance- Malassezia furfur.

11. Laboratory Diagnosis (Cont..) 11 Culture: SDA with olive oil overlay - ‘ fried egg ’ colonies- Malassezia furfur appear after incubating for 5–7 days at 32–35°C Urease test: positive Wood’s lamp examination: golden yellow fluorescence. White Piedra- : Trichosporon beigelii , yeast like fungus, arthrospores Black Piedra- Piedraia hortae - Phaeoid fungus

12. Dermatophytoses 12 Dermatophytoses (or tinea or ringworm) - most common superficial mycoses affecting skin, hair and nail- infecting keratinized tissues- inflammatory & HST reaction Classification Trichophyton species : Infect skin, hair and nail Microsporum species : Infect skin and hair Epidermophyton species : Infect skin and nail

13. Pathogenesis 13 Acquired by direct contact with soil, animals or humans infected with fungal spores Predisposing factors - moist humid skin and tight ill-fitting underclothing Fungal products: local inflammation Hypersensitivity to fungal antigens Severity depends on the infecting fungi, immune status of the host and the site of lesion

14. Clinical Types 14

15. Ring worm infections (Tinea) 15 Tinea capitis ( favus ); Tinea faciei ; Tinea pedis ; Tinea corporis .

16. TENIA CAPITIS Favus : dense crusts ( scutula ) develop in the hair follicles – leads to alopecia & scarring Kerioon : boggy lesions with marked inflammatory reactions

17. Causative agents DISEASE COMMON CAUSATIVE AGENTS Tinea capitis Microsporum any spp., trichophyton most spp. Favus T.schoenleinii , T. violaceum , M. gypseum Tinea barbae T. rubrum , T. mentagrophytes , T. verrucosum Tinea imbricata T. concentricum Tinea corporis T. rubrum & any other dermatophyte Tinea cruris E. floccosum , T. rubrum Tinea pedis T. rubrum , E. floccosum Ectothrix hair infection Microsporum spp., T. rubrum , T. mentagrophytes Endothrix hair infection T.schoenleinii , T. tonsurans , T. violaceum

18. LABORATORY DIAGNOSIS Sample collection Scraping from the edge of the lesions Infected hair to be plucked out – ectothrix / endothrix Infected nail clippings KOH mount Culture on SDA with antibiotics & cycloheximide – incubated at R.T. Growth slow – 1-3 weeks

19. Sample collection

20. Laboratory Diagnosis 22 Woods Lamp Examination: Positive for various Microsporum species & Trichophyton schoenleinii Fluorescence is due to the presence of pteridine pigment in cell wall

21. Laboratory Diagnosis (Cont..) 23 KOH mount or calcofluor white stain - thin septate hyaline hyphae with arthroconidia Hair – arthroconidia on the surface of shaft ( ectothrix ) or within the shaft ( endothrix )

22. Laboratory Diagnosis (Cont..) 24 Culture: SDA containing cycloheximide - incubated at 26–28°C for 4 weeks Potato dextrose agar – better sporulation Identification is made by: Macroscopic appearance of the colonies - rate of growth, texture, pigmentation, colony topography

23. Macroconidia of various dermatophyte species 25 C D E C. Trichophyton mentagrophytes ; D. Microsporum canis ; E. Epidermophyton floccosum

24. Microscopic appearance of various dermatophyte species (LPCB mount) 26 A. Trichophyton mentagrophytes ; B. Microsporum canis ; C. Epidermophyton floccosum.

25. Special types of hyphae seen in dermatophytes 27 G H I

26. Laboratory Diagnosis (Cont..) 28 Other Methods of Diagnosis: Hair perforation test: Fungi pierce hair producing wedge-shaped perforations Positive – T.mentagrophytes and M.canis Urease test: Trichophyton mentagrophytes is urease positive

27. SUBCUTANEOUS MYCOSES 29 The agents of subcutaneous mycoses usually inhabit the soil They enter the skin by traumatic inoculation with contaminated material- thorn prick Tend to produce granulomatous lesions in the subcutaneous tissue Eg Mycetoma, rhinosporidiosis , sporotrichosis, chromoblastomycosis

28. SUBCUTANEOUS MYCOSES 30 Sprotrichosis -lymphocutaneous mycosis- Sprothrix schenckii - thermally dimorphic fungus

29. Mycetoma 31 Chronic, slowly progressive granulomatous infection of the skin and subcutaneous tissues Triad: Swelling, discharging sinuses and presence of granules in the discharge Maduramycosis or Madura foot - first described in Madurai-John Gill (1842) Eumycetoma – caused by fungi Actinomycetoma – Caused by bacteria Bacterial (botryomycosis)- Staphylococcus, Streptomyses

30. Clinical Manifestations 32 Clinical triad 1. Tumor like swelling (tumefaction) 2. Discharging sinuses 3. Granules in sinuses Commonest site – Feet (Hands, back) Osteolytic or osteosclerotic bony lesions Usually painless

31. Laboratory Diagnosis 33 Specimen Collection: Grains/ Granules/ biopsy collected on sterile gauze by pressing the sinuses from periphery or by using a loop Direct Examination: Granules washed in sterile saline; crushed between the slides and examined

32. Laboratory Diagnosis (Cont..) 34 Macroscopic appearance of granules - color , size, shape, texture Suspected Eumycetoma : KOH mount - hyphae of 2–6 μm width along with chlamydospores at margin Suspected Actinomycetoma : Gram staining - filamentous gram positive bacilli (0.5–1 μm wide) Modified acid fast stain – Nocardia is weekly acid fast

33. Laboratory Diagnosis (Cont..) 35 Histopathological staining and KOH of the granules:

34. Laboratory Diagnosis (Cont..) 36 Culture: Granules - best specimen for culture Both fungal (SDA) and bacteriological media (Lowenstein Jensen medium, Blood agar) - inoculated Eumycetoma agents - growth rate, colony morphology, production of conidia and their sugar assimilation patterns

35. Other Subcutaneous Mycoses Sporotrichosis- Lymhocutaneous Chrmoblastomycosis - slow growing and polymorphic - verrucose (most common type), crusted, ulcerative and nodular or tumor -like lesions, Caused by darkly pigmented fungi- that produce a characteristic morphology called sclerotic body- Fonsecaea pedrosoi, Phialophora verrucosa, Cladosporium carrionii Rhinosporidiosis - rhinosporidium seeberi - now considered protista - not cultivable 37

36. Laboratory Diagnosis (Cont..) 38 Microscopy- Asteroid body - central basophilic yeast cell surrounded by radiating extensions of eosinophilic mass, composed of antigen-antibody complexes- sporotrichosis , also observed in zygomycosis , candidiasis, aspergillosis and blastomycosis Sclerotic bodies: brown thick walled round cells (5–12 μm size) with multiple internal transverse septa - also called Medlar bodies or muriform cells or “copper pennies.”- Chromoblastomycosis

37. Laboratory Diagnosis (Cont..) 39 Culture: Definitive tool for diagnosis. Specimens - inoculated onto SDA and blood agar in duplicate - incubated at 25 °C and 37°C simultaneously - S. schenckii is a dimorphic fungus At 25°C: Produces mycelial form - slender delicate hyphae with conidia arranged in - flower-like pattern. At 37°C: Produces yeast form - moist creamy white colonies which turn brown black in 10–14 days.

38. OPPORTUNISTIC MYCOSES OF SKIN 40 Penicillium marneffei - thermally dimorphic fungus, Renamed as - Talaromyces marneffei Causes opportunistic infection in HIV-infected patients. Skin lesions: Warty lesions mimicking that of molluscum contagiosum Lab Diagnosis- Histopathological staining- oval or elliptical yeast cells with central septation Culture on SDA- black pigment

39. Candidiasis 41 Candida species are the most common fungal agent to cause lesions of skin and mucosa. Oropharyngeal candidiasis : white, adherent, painless patch Vulvovaginitis: pruritus, pain, and vaginal discharge (whitish curd like in severe cases) Balanitis and balanoposthitis Esophageal candidiasis