Superficial Cutaneous And Subcutaneous

Question 1

Tinea (Pityriasis) Versicolor Presentation and Transmission

Answer 1

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

Question 2

Visualization of M. Furfur

Answer 2

Direct visualization by microscopy: spaghetti and meatballs
Culture on agar supplemented with oil
Lesions fluoresce yellow under wood lamp, pink under UV light

Question 3

Tinea Nigra presentation and Transmission

Answer 3

Hortaea werneckii
Solitary irregular pigmented macule: brown/black on palms/soles
Traumatic inoculation in superficial layers of epidermis (countries with warm climate)

Question 4

Visualization of H. werneckii

Answer 4

KOH mount: follow up with culture
Two called oval yeast and short hyphae confined to outer layers of stratum corneum
Differential: malignant melanoma

Question 5

White Piedra

Answer 5

Trichosporon
White-brown swelling around hair shaft of groin or axilla
Yeast-like fungus

Question 6

Black piedra

Answer 6

Piedraia Hortae

Small dark nodules surrounding the hair shaft of scalp

Question 7

Treatment for superficial mycoses

Answer 7

Infected skin treated topically: Ketoconazole, Selenium sulfide (tinea versicolor)

Infected hair clipped or shaved

Question 8

Cutaneous mycoses

Answer 8

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

Question 9

Epidermophyton

Answer 9

E. Floccosum
Infect skin and nails (rarely hair)
Form yellow cottony cultures
Thick bifurcated hyphae with multiple smooth club-shaped macroconidia (no micro)

Question 10

Microsporum species

Answer 10

Infect skin and hair (rarely nails)
Many rough thick-walled macroconidia: spindle shape and spiny
Fluoresces bright green under wood lamp

Question 11

Trichophyton species

Answer 11

Infect skin, hair and nails
Numerous microconidia with variety of shapes
Macroconidia rare but small and thin walled

Question 12

Tinea capitis

Answer 12

Tineas of the scalp, eyebrows, and eyelashes

Hair does not grow back

Question 13

Tinea barbae

Answer 13

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

Question 14

Tinea corporis

Answer 14

Inflammatory or non inflammatory lesions on the glamorous skin (excludes skin of scalp, groin, palms, and soles
Pruritic, annular plaque: burning, itching

Question 15

Tinea cruris

Answer 15

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

Question 16

Tinea pedis

Answer 16

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

Question 17

Tinea unguided or Onychomycosis

Answer 17

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

Question 18

Treatment for cutaneous mycoses

Answer 18

Topical ointment for mild skin disease: Terbinafine cream or Topical azoles

Oral therapy for hair, nails, or severe skin disease: Terbinafine or itraconazole

Question 19

Features of Sporotrichosis

Answer 19

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

Question 20

Types of Sporotrichosis

Answer 20

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

Question 21

Lymphocutaneous Sporotrichosis pathogenesis and clinical findings

Answer 21

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

Question 22

Sporotrichosis causative agent

Answer 22

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

Question 23

Sporotrichosis diagnosis

Answer 23

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

Question 24

Treatment of Sporotrichosis

Answer 24

Spontaneous healing possible
Lymphocutaneous treated with itraconazole
Disseminated infection treated with Amphotericin B