1 9/7/2015 medical mycology: superficial, cutaneous and subcutaneous mycoses hugh b. fackrell
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Medical Mycology:Medical Mycology:Superficial, Cutaneous and Superficial, Cutaneous and
Subcutaneous MycosesSubcutaneous MycosesHugh B. Fackrell
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Mycoses & MytoxicosisMycoses & Mytoxicosis
Mycoses: fungal infections Mytoxicosis: intoxicaton
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Fungal DiseaseFungal Disease
Mycoses Colonization of the host Mycotoxicosis: Intoxication Hypersensitivity
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Fungal EntryFungal Entry
Rarely cause disease in healthy person Commensal
– Candida albicans– Malasseza fufur
Underlying disorder– trauma– immunological deficiency– debilitating conditions
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Disease Mechanisms of FungiDisease Mechanisms of FungiEndogenous Opportunistic Iatrogenic
– (physician induced)
– e.g. indwelling lines catheters
Exogenous Opportunistic
– inhalation
Superficial– Trauma hygiene
Cutaneous– trauma
Subcutaneous– trauma
Systemic– inhalation
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Fungal DisseminationFungal Dissemination
Breach in host defenses– endocrinopathies– immune disorders– iatrogenic
Must repair defect
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Host Defense FactorsHost Defense Factors
Intact skin long chain fatty acids pH Bacterial antagonism corneum stratum
desiccated epithelial cell turnover
rate (0.5 kg/yr.)
Mucous membranes ciliated antimicrobials Immunological
competence
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Fungal InfectionsFungal Infections
Opportunistic Infections
Superficial fungal infectionsCutaneous MycosesSubcutaneous Mycoses Systemic Mycoses
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Structure of SkinStructure of Skin
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Superficial Fungal InfectionsSuperficial Fungal Infections
Skin Infections– limited to Stratum corneum– do not penetrate deeper tissues
No inflammation
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Superficial mycosesSuperficial mycoses
Pityriasis versicolor Black piedra White piedra tinea nigra
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Black PiedraBlack Piedra
Superficial mycosis
Piedraia hortai small firm black
nodule Surrounds hair
shaft
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White PiedraWhite Piedra
Superficial mycosis Trichasporon beigelii soft friable beige
nodule distal ends of hair
shaft
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Pityriasis VersicolorPityriasis Versicolor Common superficial
mycosis Superficial keratin
layer hypo or hyper
pigmentation on skin of neck shoulders chest and back
Malassezia furfur
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Malassezia furfurMalassezia furfur
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Tinea NigraTinea Nigra Superficial mycosis Phaeoannellomyces werneckii silver nitrate type of stain palm of hand
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Cutaneous MycosesCutaneous Mycoses
Dermatophytoses Dermatomycoses
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DermatophytosesDermatophytoses
Cutaneous Mycoses Secrete keratinolytic enzymes which dissolve
the skin protein KERATIN Three genera
– Epidermophyton.– Microsporum,– Trichophyton
Anatomic specificity correlates with genus– -skin,hair,nails.
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EpidermophytonEpidermophyton
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MicrosporumMicrosporum
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MicrosporumMicrosporum
EctothrixSpores on outside of hair follicle
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MicrosporumMicrosporum
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MicrosporumMicrosporum
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Microsporum Microsporum
Spores of Microsporum lie outside the hair shaft. This is known as ECTOTHRIX
Can be seen with an ultra violet lamp called a “Woods” light. Bright fluorescence.
Children are more susceptible than adults, because post pubertal sebum has fungistatic fatty acids especially M.audouinii
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Microsporum audouinii,canisMicrosporum audouinii,canis
M.audouinii -Predominant species in temperate climates.
Very contagious can cause epidemics
Spread by barbers tools, seat head rests
M.canis- Second most common- spread by kittens, pups - young animals
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TrichophytonTrichophyton
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TrichophytonTrichophyton
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TrichophytonTrichophyton
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TrichophytonTrichophyton
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Dermtaophytes:Dermtaophytes:Tinea InfectionsTinea Infections
Tinea capitis - Head, scalp, neck Tinea barba - Face Tinea corporis - Body Tinea.cruri - Groin, perineum Tinea pedis - Feet Tinea unguium -Nails
TINEA means RINGWORM
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Tinea capitisTinea capitis
Ringworm of the scalp-very contagious- especially pre-pubertal children.
Begins with small, itchy, scaling papule
spreads peripherally makes a roundish lesion,
Hair breaks off at scalp level, leaving a patch.
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Tinea CapitisTinea Capitis
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Tinea corporisTinea corporis
Ringworm of the body,with annular lesions the centre is scaly and the periphery advancing circle of vesicles and papules.
Prefers areas that are hairy soon to become bare due to the fungus.
Associated with poor nutrition and hygiene but is also common in persons who frequent gymnasiums and pools.
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Tinea pedis Tinea pedis
Tinea pedis - “Athletes foot”skin cracks between toes, maceration of tissue,desquamation, ulcerations, can spread whole bottom foot.
Epidermophyton and Trychophyton. ~ 2% carry fungus no symptoms.men susceptible
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Tinea PedisTinea Pedis
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Tinea crurisTinea cruris
T.cruris- Groin, perineum,perianal region Epidermophyton floccosum or inguinale. Tight pants,perspiration,pubic contact.
Epidermophyton and Trychophyton. ~ 2% carry fungus no symptoms.men susceptible
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Tinea CrurisTinea Cruris
Epidermophyton
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Tinea unguiumTinea unguium
Nails brittle thick,discoloured, grooved.
Trichophyton rubrum most common in women aged 40-50
Persistent very difficult to treat. Antibiotics cannot be effective.
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DermatomycosesDermatomycoses
Cutaneous fungal infections inflammation caused by opportunistic fungi Candida spp
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Cutaneous Mycoses:Cutaneous Mycoses:TreatmentTreatment
Mild cases topical treatment
3% sulfur+3% salicylic acid ointment
1% crystal violet
1% iodine
1% tolnaftate
10% undecylenic acid
miconazole haloprogin
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Cutaneous MycosesCutaneous MycosesTreatment Treatment
Serious or stubborn cases
Griseofulvin - 1gram /day for 1-3 months
This antimicrobial extracted from cultures of Penicillium griseofulvum in 1939 not used as a drug until 1959
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Subcutaneous MycosesSubcutaneous Mycoses
Caused by trauma [puncture]and introduction of the fungus and bacteria.
Chromoblasomycosis Phaeohypomycosis Mycetoma Sporotrichosis
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ChromoblastomycosisChromoblastomycosis
Subcutaneous mycosis verrucoid skin lesions lower extremities Histology muriform cells- cross walls in two
directions no involement of bone tendon or muscle
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PhaeohypomycosisPhaeohypomycosis
Infections caused by dermatiaceous fungi hyphal to yeast forms in tissue
Dermatiaecous Fungi– melanin black fungi
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MycetomaMycetoma
Granulomatous local lesions – usually of the legs and feet – infect humans who have extensive contact with
soil and foliage due to bare feet and legs. Suppuration
– small visible pigmented grains or granules– microcolonies
Destroys bone tendon and muscle
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MycetomaMycetoma
caused by many organisms Eumycotic mycetoma
– fungal
– USA Pseudallescheria boydii Actinomycotic mycetoma
– bacterial
– USA Nocardia brailiensis Madura foot
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Sporotrichosis Sporotrichosis
world wide-Sporothrix schenkii ulcerative lesions at site on injured skin
usually arm, spread to the regional lymph nodes. The high risk group, gardeners, farmers who work with wood/ soil.
Highly infectious on contaminated dressings to patients with wounds.
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Sporotrichosis Sporotrichosis
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Sporotrichosis Sporotrichosis
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Sporotrichosis Sporotrichosis
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Treatment of sporotrichosis Treatment of sporotrichosis
– topical potassium iodide– amphotericin B systemically.