1 9/7/2015 Medical Mycology: Superficial, Cutaneous and Subcutaneous Mycoses Hugh B. Fackrell.

transcript

04/21/23

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

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White PiedraWhite Piedra

Superficial mycosis Trichasporon beigelii soft friable beige

nodule distal ends of hair

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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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EctothrixSpores on outside of hair follicle

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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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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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Treatment of sporotrichosis Treatment of sporotrichosis

– topical potassium iodide– amphotericin B systemically.

1 9/7/2015 Medical Mycology: Superficial, Cutaneous and Subcutaneous Mycoses Hugh B. Fackrell.

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