Mycoses: Superficial Infections and Dermatophytes

Questions and Answers

Match the following types of tinea with their primary affected area:

Tinea pedis = Feet Tinea manuum = Hands Tinea nigra = Palms or soles Acral lentiginous melanoma = Arms

Match the following types of fungi with their characteristics:

Dematiaceous fungi = Darkly pigmented Hortaea werneckii = Causes tinea nigra Stenella araguata = Causes tinea pedis Phaeoannellomyces werneckii = Causes skin cancer

Match the following regions with the prevalence of tinea nigra:

Tropical or subtropical areas = High incidence United States and Europe = Low incidence Central and South America = Endemic foci Asia = Only found in tourists

Match the following clinical findings with the corresponding type of tinea:

Asymptomatic, mottled brown to greenish-black macule = Tinea nigra Scaly patches = Tinea pedis Itchy skin = Tinea manuum Painful sores = Acral lentiginous melanoma Signup and view all the answers

Match the following types of transmission with the corresponding type of tinea:

Person-to-person transmission = Rare in tinea nigra Through contact with contaminated soil = Tinea pedis Through contaminated water = Tinea manuum Through touching infected animals = Tinea nigra Signup and view all the answers

Match the following characteristics with the corresponding type of tinea:

Female-to-male predilection of 3:1 = Tinea nigra More common in men = Tinea pedis Affects only children = Tinea manuum Affects only older adults = Acral lentiginous melanoma Signup and view all the answers

Match the following types of tinea with their causative agents:

Tinea nigra = Hortaea werneckii Tinea pedis = Stenella araguata Tinea manuum = Phaeoannellomyces werneckii Acral lentiginous melanoma = Dematiaceous fungi Signup and view all the answers

Match the following clinical presentations with the corresponding type of tinea:

Mottled brown to greenish-black macule = Tinea nigra Scaly patches = Tinea pedis Itchy skin = Tinea manuum Painful sores = Acral lentiginous melanoma Signup and view all the answers

Match the following types of tinea with their common misdiagnosis:

Tinea nigra = Acral lentiginous melanoma Tinea pedis = Tinea manuum Tinea manuum = Tinea pedis Acral lentiginous melanoma = Tinea nigra Signup and view all the answers

Match the following regions with the existence of endemic foci:

Coastal southeastern United States = Yes Texas = Yes Central and South America = No Africa = Only in tourists Signup and view all the answers

Study Notes

Mycoses

Divided into 3 forms: superficial, subcutaneous, and deep/systemic
Superficial mycoses involve stratum corneum, hair, and nails
Subcutaneous mycoses involve dermis and/or subcutaneous tissue
Deep/systemic mycoses represent hematogenous spread of organisms in immunocompromised hosts

Dermatophytes

Comprise approximately 40 species divided among 3 genera: Trichophyton, Microsporum, and Epidermophyton
Belong to the Arthrodermataceae family
Trichophyton species (e.g., Trichophyton rubrum and Trichophyton interdigitale) are the most common isolated species in the United States
Classified according to their natural habitats: humans, other animals, and soil
Attach to, invade, and use keratin as a source of nutrition, underlying the pathogenesis of superficial fungal infection of skin, hair, and nails (dermatophytosis)

Tinea Capitis

Describes a dermatophyte infection of hair and scalp typically caused by Trichophyton and Microsporum species
Majocchi granuloma is a superficial and subcutaneous dermatophytic infection involving deeper portions of the hair follicles
Presents as scaly, follicular papules and nodules that coalesce in an annular arrangement
Most commonly caused by T. rubrum, T. interdigitale, and M. canis

Tinea Corporis

Dematophyte infection of skin
Typically caused by T. rubrum
Presents as classic annular or "ringworm"-like configuration with an advancing raised erythematous and scaly border
Can resemble psoriasis

Favus

A dermatophyte infection of the scalp
Characterized by patchy perifollicular erythema with slight scaling and matting of the hair
Progressive hyphal invasion distends the follicle, producing a yellow-red follicular papule, then a yellow concave crust (scutulum) around a single dry hair
Most commonly caused by T. schoenleinii, with T. violaceum and M. gypseum as rare isolates

Tinea Manuum and Tinea Pedis

Tinea manuum is discussed with tinea pedis under the section "Tinea Pedis and Tinea Manuum"

Tinea Nigra

A superficial dermatomycosis caused by dematiaceous, darkly pigmented Hortaea werneckii
Occurs in tropical or subtropical areas, with low incidence in the United States and Europe
Presents as an asymptomatic, mottled brown to greenish-black macule or patch with minimal to no scale on the palms or soles
Frequently misdiagnosed as acral lentiginous melanoma

Description

Test your knowledge on the different types of mycoses, including superficial, subcutaneous, and deep/systemic infections. This quiz focuses on superficial mycoses, dermatophytes, and their impact on the integumentary system.