25 Questions
What is the primary site of infection in Sporotrichosis?
Feet and lower extremities
What is the characteristic of fungi in Phaeohyphomycosis?
Fungal elements are brown pigmented
Which of the following is a diagnostic method for Sporotrichosis?
Direct microscopic examination
What is the term for a fungal infection of the skin, hair, or nails?
Dermatomycosis
What is the characteristic of the colonies of Sporothrix schenckii in Sabouraud's dextrose agar?
Black and shiny
Which of the following is a treatment option for Sporotrichosis?
Combining miconazole and surgery
Which type of dermatophytosis is commonly found in children?
Tinea capitis
What is the name of the dermatophytosis that affects the bearded areas of the face and neck?
Tinea barbae
Which of the following is NOT a type of dermatophytosis?
Sporotrichosis
What is the term for the ringworm infection of the skin and hair?
Tinea corporis
Which of the following is NOT a characteristic of dermatophytosis?
Infection of the deeper layers of the skin
What is the term for the dermatophytosis that affects the nails?
Tinea unguium
What is the primary mode of infection for Mycetoma?
Trauma to the skin by plant materials
Which of the following is a common symptom of Histoplasmosis?
Chest pain
What is the primary site of infection for Coccidioidomycosis?
Lungs
Which of the following fungi can cause skin and bone infections?
H. capsulatum var. duboisii
What is the name of the disease caused by Paracoccidioides brasiliensis?
South American blastomycosis
Which of the following is a manifestation of hypersensitivity to Coccidioides immitis antigens?
Erythema nodosum
What is the name of the fungi that causes Mycetoma?
Eumycetoma
What is the diagnosis method for Tinea Nigra?
Microscopic examination of skin scrapings
What is the treatment for dermatophytosis?
Topical azoles or selenium sulfide shampoo
What is the causative agent of Tinea Nigra?
Hortaea werneckii
What is the characteristic appearance of Tinea Nigra?
Irregular, pigmented (brown to black) macule
Which of the following is NOT a type of opportunistic mycoses?
Dermatophytosis
What is the typical location of Tinea Nigra?
Palms or soles
Study Notes
Dermatophytes
- 3 Genera: Trichophyton, Microsporum, and Epidermophyton
- Keratinophilic and keratinolytic, invade only the upper outermost layer of the epidermis (stratum corneum)
- Infections:
- Trichophyton: skin, hair, and nails
- Microsporum: skin and hair
- Epidermophyton: skin and nails
Dermatophytosis
- Infection named according to anatomic location involved
- Types of infections:
- Tinea corporis: small lesions on the body
- Tinea barbae: ringworm of the bearded areas of the face and neck
- Tinea pedis: athlete's foot, infection of toe webs and soles of feet
- Tinea unguium (onychomycosis): infection of the nails
- Tinea capitis: infection of the head, frequently found in children
Ecology of Dermatophytes
- Source of infection:
- Anthropophilic: person-to-person transmission through contaminated objects
- Zoophilic: associated with animals, direct transmission to humans through close contact
- Geophilic: usually found in soil, transmitted to humans through direct exposure
Laboratory Diagnosis
- Demonstration of fungal hyphae by direct microscopy of skin, hair, or nail samples
- Isolation of organisms in culture
Treatment
- Thorough removal of infected and dead epithelial structures
- Application of topical antifungal chemicals
- Prevention of reinfection: keep the area dry, avoid sources of infection (e.g., infected animals or shared bathing facilities)
Superficial Mycoses
- Colonize the keratinized outer layers of the skin, hair, and nails
- Asymptomatic, mostly a cosmetic concern
- Examples:
- Pityriasis (Tinea) Versicolor
- Tinea Nigra
- White Piedra
- Black Piedra
Pityriasis (Tinea) Versicolor
- Causative agent: Malassezia furfur
- Lesions: small, hypopigmented or hyperpigmented macules
- Clinical findings:
- Site: feet, lower extremities, hands
- Findings: abscess formation, draining sinuses containing granules, deformities
- Dissemination: muscles and bones
Sporotrichosis
- Causative agent: Sporothrix schenckii
- Initial lesion: granulomatous nodule that will ulcerate and become necrotic
- Multiple subcutaneous nodules occur along the lymphatic vessels
Phaeohyphomycosis
- Cutaneous phaeohyphomycosis: characterized by the presence of brown pigmented fungal elements
- Fungi: usually pigmented dark brown
- Infections: may become invasive and systemic (invading various organs)
Learn about dermatophytes, fungi that cause skin, hair, and nail infections, and dermatophytosis, the infection caused by these fungi.
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