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2-Superficial, Cutanous &systemic.ppt
- 1. Mycoses: diseases causeby fungi Mycoses are classified into the following categories: • Superficial • Cutaneous • Subcutaneous • Systemic • Opportunistic • Mycotoxicoses Mycoses: Tend to be chronic because fungi grow slowly.
- 2. Superficial mycoses • Prevalentin tropical climates. • Are fungal infections confined to the outer most dead layers of skin, hair and nails • do not penetrate deeper tissues • Do not elicit a cellular response from the host. • Infections are generally painless. • No inflammation • symptoms - discoloration, scaling, or de-pigmentation of the skin. • Superficial mycoses – Black piedra – White piedra – Pityriasis versicolor – tinea nigra
- 3. Superficial mycoses Piedra isa fungal infection of the hair, characterized by the presence of stony hard nodules along the hair shaft a) Black Piedra • This disease is characterized by small dark nodules seen on the hair shaft. • Caused by Piedraia hortai • The lesion is very discrete, surrounds the hair shaft and is dark brown.
- 4. Superficial mycoses b) WhitePiedra • caused by Trichosporon beigelii • Produces light brown soft nodules on the beard • less firmly attached than those of black piedra
- 5. Superficial mycoses C. Tineaversicolor (Pityriasis) • This is a very common superficial mycoses caused by a lipophilic yeast Malassezia spp • The lesions are hypo or hyper pigmented. • The etiologic agent is normal flora of man so the disease re- occurs.
- 6. Superficial mycoses d. Tineanigra • caused by Exophiala werneckii • asymptomatic fungal infection usually involves the palms of the hand • Lesions are dark brown to black with little scaling.
- 7. Laboratory Diagnosis Direct Examination •Scales should be scraped from the fawn colored macules with a scrapler and mounted directly on a slide in a drop of 10% potassium hydroxide Culture and identification • Specimen from lesions should be inoculated on sabouraud’s dextrose agar (SDA) plate or slants at room temperature and held for 3 weeks before being discarded
- 8. CUTANEOUS MYCOSES(Dermatophytoses) • Refersto certain fungal infection of the skin caused by dermatophytes. • Fungi of dermatophyte group invade only cutaneous skin and its appendages such as hair and nails alone or in combination • diseases of the skin, hair, and nails • involves the keratinized layers of the skin and its appendages o Generally called “Ringworms” or “ Tineas” (Latin for ringworms) o Spreads in a centrifugal pattern forming a ring • Etiological agents are called dermatophytes - "skin plants". • Dermatophytes are keratinophilic - "keratin loving". • Keratin is a major protein found in horns, hooves, nails, hair, and skin.
- 9. Cutaneous mycosis cont’d… Modeof transmission • Infection is transmitted by direct contact or contact with infected hair (hair salon) or cells (nail files, shower floors). • Transmission of dermatophytic infection enhanced by conditions of high moisture and sweating, and retention of moisture increases the possibility of contracting infections.
- 10. Clinical manifestations ofringworm infections are called different names on basis of infection sites • tinea capitis - ringworm infection of the head, scalp, • tinea corporis - ringworm infection of the body (smooth skin) • tinea cruris - ringworm infection of the groin (jock itch) • tinea unguium - ringworm infection of the nails • tinea barbae - ringworm infection of the beard • tinea manuum - ringworm infection of the hand • tinea pedis - ringworm infection of the foot (athlete's foot)
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- 17. Diagnosis of dermatophytes •Note the symptoms. • Note the kind of tissue attacked 1. Direct Microscopy--- 10 % KOH – KOH digest the keratin--- and enable the fungal elements to be seen clearly – Not sensitive 2. culture – Sabouraud Dextrose Agar (SDA Dermatophyte Test medium (DTM)—selective medium • SDA, • cycloheximide, • Antibiotic, phenol red
- 18. KOH preparation • areused in the initial examination of keratinized tissue suspected of fungal infection. Principle • Fungal elements may be obscured by skin, hair, or nail tissue. • KOH (20%w/v) dissolves keratin in skin, hair or nail specimens, facilitating the observation of the organism’s morphology.
- 19. Treatment Skin infections – Infectedskin may be treated with topical application of antifungal agents miconazole and clotrimazole – Refractory lesions oral griseofulvin and itraconazole, terbinafine Infections of hair and nails – usually require systemic ( oral) therapy
- 20. Subcutaneous mycoses Fungalinfections beneath the skin- Subcutaneous tissues dermis of the skin, deep tissues or bone. • Causative organisms reside in the soil and in decaying or live vegetation • Almost always acquired through traumatic lacerations or puncture wounds • Common among those who work with soil and vegetation and have little protective clothing--- occupational • Not usually transmitted humans to humans • Mycetoma • Chromoblastomycosis • Sporotrichosis
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- 23. Sporotrichosis • chronic infectioncaused sporotrichum schenckii- dimorphic fungus • Sporotrichum schenckii exists in nature where it has been isolated from soil, wood and plants. • Human bieng and animals become infected by contact with contaminated materials at the time of an injury to the skin of hand, arm and leg, and inhalation. • The infection is an occupational hazard - farmers • It is commonly known as “rose gardener’s”disease • Yeast travel along lymphatics • Elicit mixed pyogenic/ granulomatous reaction • Granauloma ulcer at a puncture skin usually a thorn prick and may produce secondary lesions along draining lymphatics
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- 25. Systemic / Deep/ Mycoses DIMORPHIC MYCOSES
- 26. 26 Systemic / Deep/ Endemic Mycoses • Caused by true pathogens (infect both healthy and immunocompromised patient) • Caused by endemic dimorphic fungi • Dimorphic:- • exist in a mould form or in nature or in the laboratory at 250C to 300c and • in yeast in tissues or in culture media in laboratory at 370C • Endemic/occur only in certain regions of the world
- 27. Systemic mycosis… con’t •Infection is commonly acquired by inhalation of spores from the environment and may spread form the lung to other sites • Inhalation pulmonary inf. dissemination • Most infections are asymptomatic or self-limiting • In immune-compromised hosts, infections are more severe and often fatal Clinical pictures • Primary infection: – Fever, chest pain, cough, weight loss – Nodular lesions in lungs • Secondary (disseminated) infection:
- 28. 28 28 Systemic Mycosis includes 1.Histoplasmosis 2. Blastomycosis 3. Coccidioidomycosis 4. Paracoccidioidomycosis
- 29. HISTOPLASMOSIS • Caused by---Histoplasma capsulatum • Dimorphic soil organism • The fungus is found in soil, in decaying plant materials, but especially in droppings of bats and some birds • Transmission: Inhalation of air-borne asexual spores (conidia) • Spores transform to yeast in lung, elicit cellular immunity as per TB--- clinically mimics TB • An intracellular mycoses of the reticuloendothelial system, attacking lungs, liver, spleen, bone marrow • skin test reactivity (histoplamin)
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- 31. Blastomycosis • Sub-acute &chronic fungal infection. • Etiologic agent: Blastomyces dermatitidis • It affects lungs, skin and bone • Infection--- inhalation of spores • Pathophysiology_-- Spores transform into yeast in lung, disseminate • Causes --primary pulmonary blastomycosis and cutanous • The more common is the secondary form resulting from dissemination from a lung lesion which manifests as nodules, gummata, abscesses and ulcers in various regions of the body • Later nodular, verrucous and ulcerous lesions develop
- 32. Ulcerated granuloma dueto B. dermatitidis.
- 33. 33 Coccidioidomycosis • Caused byC. immitis • C.immitis is found in soil --enhanced by bat and rodent dropping. • C.immitis is probably the most virulent • Inhalation of a few arthroconidia produce 10 infection which result asymptomatic or a self limited flue like illness • Spores transform to spherules in lung, elicit cellular immunity as per TB • Like syphilis and tuberculosis coccidiodomycosis causes a wide varieties of lesions and has been called the great imitator. • Disseminated infection (Extra pulmonary infection) includes skin, soft tissues, bones, joints, and meninges • Skin test reactivity (coccoidin)
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- 35. 35 Chronic cutaneous coccidioidomycosis showinggranulomatous lesions of the face, neck and chin Extension of pulmonary coccidioidomycosis showing a large superficial, ulcerated plaque Lesion may present as small papular nodules, ulcerated nodules, or verrucous granuloma
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