Superficial Cutaneous And Subcutaneous Flashcards
Tinea (Pityriasis) Versicolor Presentation and Transmission
Malassezia furfur
Small hypo or hyperpigmented macules: irregular demarcated, can affect any part of body
Infected keratinous material, direct or indirect, from one person to another
Visualization of M. Furfur
Direct visualization by microscopy: spaghetti and meatballs
Culture on agar supplemented with oil
Lesions fluoresce yellow under wood lamp, pink under UV light
Tinea Nigra presentation and Transmission
Hortaea werneckii
Solitary irregular pigmented macule: brown/black on palms/soles
Traumatic inoculation in superficial layers of epidermis (countries with warm climate)
Visualization of H. werneckii
KOH mount: follow up with culture
Two called oval yeast and short hyphae confined to outer layers of stratum corneum
Differential: malignant melanoma
White Piedra
Trichosporon
White-brown swelling around hair shaft of groin or axilla
Yeast-like fungus
Black piedra
Piedraia Hortae
Small dark nodules surrounding the hair shaft of scalp
Treatment for superficial mycoses
Infected skin treated topically: Ketoconazole, Selenium sulfide (tinea versicolor)
Infected hair clipped or shaved
Cutaneous mycoses
Fungal infection of keratinized layer of skin, hair, or nails but do not invade tissues
Caused by dermatophytic fungi (dermatomycosis)
Able to digest keratin by secreting keratinase
Resistant to cycloheximide
Anthrophillic, geophillic, zoophilic
Epidermophyton
E. Floccosum
Infect skin and nails (rarely hair)
Form yellow cottony cultures
Thick bifurcated hyphae with multiple smooth club-shaped macroconidia (no micro)
Microsporum species
Infect skin and hair (rarely nails)
Many rough thick-walled macroconidia: spindle shape and spiny
Fluoresces bright green under wood lamp
Trichophyton species
Infect skin, hair and nails
Numerous microconidia with variety of shapes
Macroconidia rare but small and thin walled
Tinea capitis
Tineas of the scalp, eyebrows, and eyelashes
Hair does not grow back
Tinea barbae
Bearded areas of face and neck
Older adolescents and adult males
Inflammatory, deep, kerionlike plaques and non inflammatory superficial patches resembling tinea corporals or bacterial folliculitis
Tinea corporis
Inflammatory or non inflammatory lesions on the glamorous skin (excludes skin of scalp, groin, palms, and soles
Pruritic, annular plaque: burning, itching
Tinea cruris
Jock itch
Fungal infection of groin and adjacent skin
Manifests as a symmetric erythematous rash
Scale demarcated at the periphery
Acute: moist and exudative
Chronic: dry with papular annular or arciform border
Tinea pedis
Athletes foot
Most common dermaphytoses
Fungal infection of soles of feet and interdigital spaces
Pruritic, scaly soles
Painful fissures between toes
Less often vesicular or ulcerative lesions
Tinea unguided or Onychomycosis
Fungal infection of nails (more common in toes than fingers)
Begins as discoloration at a corner of nail and works way toward cuticle
Nail eventually becomes thickened and flaky
Treatment for cutaneous mycoses
Topical ointment for mild skin disease: Terbinafine cream or Topical azoles
Oral therapy for hair, nails, or severe skin disease: Terbinafine or itraconazole
Features of Sporotrichosis
Chronic infection involving cutaneous, subcutaneous, and lymphatic tissues
Frequently encountered in gardeners (rose gardeners disease)
May develop in heathy individuals
Most common in Mexico, endemic in Brazil, Uruguay, South Africa
Types of Sporotrichosis
Subcutaneous or lymphocutaneous: primary lesion in distal and travels up lymphatics, causes minimal pain, typically afebrile and does not become systemic
Pulmonary: pts with underlying COPD, subacute or chronic PNA, alcoholic rose gardeners disease
Osteoarticular: chronic
Disseminated: rarely occurs, organ involvement
Lymphocutaneous Sporotrichosis pathogenesis and clinical findings
Cutaneous inoculation
Initial papules or nodules at site of inoculation: supporting granuloma with centralized neutrophils surrounded by lymphocytes and plasma cells
Ascending chain of nodules develop along skin lymphatic channel
Older lesions ulcerated and drain
Sporotrichosis causative agent
Sporothrix schenkii
Environmental distribution: soil, bark of trees, shrubs, and garden plants
Thermally dimorphic
37C: round/cigar shaped yeast cells
25C: septate hyphae, rosette like clusters of conidiophores at tips of conidiophores
Sporotrichosis diagnosis
Direct microscopic examination of pus or sputum
Histopathological examination of biopsy: yeast cells surrounded by Splendore-Hoeppli material, asteroid body
Culture
Serology: yeast agglutination test
Treatment of Sporotrichosis
Spontaneous healing possible
Lymphocutaneous treated with itraconazole
Disseminated infection treated with Amphotericin B
