Fungal Disease Flashcards
What are the most common systemic mycoses in neutropaenic patients?
Candidiasis
Aspergillosis
HIV, is ass. with which systemic mycoses?
Histoplasmosis
Coccidiomycosis
Cryptococcosis
Talaromycosis
The following image demonstrates the microscopic appearance of which organism?
Candida species
Describe the common cutaneous presentation of systemic candidiasis
Firm erythematous papules and nodules
- often with a pale center (although can be haemorrhagic)
Ecthyma gangrenosum like lesions
Which organisms can cause systemic candidiasis?
Candida Albicans
Candida Tropicalis (frequent cut. lesions)
Candida Glabrata
Candida Krusei
What are the cutaneous features of aspergilosis?
Nectrotic papulonodules
Subcut nodules
What are the organisms that cause aspergillosis?
Aspergillus flavus and fumigatus
Which organism is depicted below?
Aspergilus
What are the cutaneous features of mucormycoses?
Ecthyma gangrenosum like lesions
Cellulitis
Facial edema
Necrotic papulonodules
Plaques
Large haemorrhagic crusts of the face
What organisms cause mucormycosis?
Mucor
Rhizppus
Lichthemeimia
What are the cutaneous features of crytococcosis?
Ulceration
Cellulitis
Molluscum contagiosum like lesions
How is aspergillosus contracted?
Primary - inhaled
Secondary - direct port of entry through compromised skin barrier
Aspergillosis and mucormycosis are angioinvasive.
True
Where is Cryptococcus neoformans found?
Pigeon droppings
Septal hyphae
= Aspergillosus
Ribbon like - non, septal hyphae
=Rhizopus (mucormycosis)
Dermal yeasts with gelatinous capsules = cryptococcus
What is the mortality of diseminated candidiasis?
20 - 60%
What organism causes histoplasmosis?
Histoplasma Capsulatum
Where is Histoplasma found?
soil - moist climates
intracellular yeast forms surrounded by a rim of clearing
Histiocytes and giant cells are the host cells in histoplasmosis
How is histoplasmosis treated?
Amphotericin B IV up to 1mg/kg/day
second line: itraconazole
List the common Trichophyton Spp
Tonsurans
Rubrum
Mentagrophytes
Interdigitale
Indotineae
Violaceum
Verrucosum
What are the classes of dermatophytes?
Microsporum,
Epidermophyton,
Trichophyton
Dermatophytes are a group of fungi that cause skin infections.
How are dermatophytes spread?
Anthropophilic (Human - Human)
Zoophilic (Animal -Human)
Geographic (Soil - Human)
These modes of transmission indicate the source of infection.
What is anthropophilic spread?
Human to human with chronic mild inflammatory response
This type of spread is common among certain dermatophytes.
What is zoophilic spread?
Animals to human with massive inflammatory response in humans
This type of spread often leads to severe symptoms.
What is geographic spread?
Soil to humans with severe inflammatory response & scarring
This type of spread is less common and involves specific species.
Which organisms exhibit anthropophilic spread?
All Trichophyton spp except T mentagrophytes and T verrucosum, E floccosum, M audouinii, M ferrugineum
These organisms primarily spread between humans.
Which organisms exhibit zoophilic spread?
M canis,
M nanum,
T verrucosum,
T mentagrophytes
These organisms are typically transmitted from animals to humans.
Which species shows geographic spread?
M. gypseum
This species is unique in its transmission from soil.
Common organisms that cause tinea capitis and are they endothrix or ectothrix?
Trichophyton tonsurans - Endothrix, Microsporum canis - Ectothrix, Trichophyton violaceum - Endothrix
Tinea capitis is a fungal infection of the scalp.
Most common cause of tinea corporis?
Trichophyton rubrum, Trichophyton mentagrophytes
Tinea corporis is also known as ringworm.
Most common cause of tinea facei?
Trichophyton rubrum, Trichophyton mentagrophytes, M canis
Tinea facei affects the face.
Most common cause of tinea pedis?
Trichophyton rubrum, Epidermophyton floccosum, Trichophyton interdigitale, Trichophyton mentagrophytes (Bullous)
Tinea pedis is commonly known as athlete’s foot.
Most common cause of onychomycosis?
Trichophyton rubrum, Trichophyton interdigitale, Epidermophyton floccosum
Onychomycosis is a fungal infection of the nails.
What are the four subtypes of tinea pedis?
Moccasin, Interdigital, Inflammatory, Ulcerative
Each subtype presents with different symptoms.
How would you treat tinea corporis?
1st line: Topical Terbinafine cream BD for 4 - 6 weeks, 2nd line: Topical Clotrimazole cream BD for 4 - 6 weeks
Systemic treatment is reserved for more severe cases.
How would you treat tinea capitis?
1st Line: Oral Terbinafine (weight-based dose), 2nd Line: Oral Griseofulvin 20mg/kg/day, 3rd Line: Oral Itraconazole 5mg/kg, Adjuncts: Ketoconazole shampoo
Systemic therapy is often necessary due to scarring risks.
How would you treat onychomycosis?
1st Line: Oral Terbinafine, 2nd Line: Oral Fluconazole, 3rd Line: Oral Itraconazole, 4th Line: Oral Griseofulvin
Topical therapy is generally ineffective for onychomycosis.
What is Tinea capitis?
A fungal infection of the scalp caused by Trichophyton tonsurans, Microsporum canis, and T. violaceum.
What is Endothrix?
A type of tinea capitis characterized by black dot and arthroconidia within the hair shaft.
Organisms include T. rubrum, T. tonsurans, T. yaunde, T. schoenleinii, T. violaceum, T. gourvilli, and T. soudanense.
What is Ectothrix?
A type of tinea capitis characterized by arthrospores around the hair shaft.
Fluorescent under Wood’s lamp. Organisms include M. canis, M. audouinii, M. gypseum, M. ferrugineum, M. distortum, and T. schoenleinii.
What is Favus (tinea favosa)?
The most severe form of tinea capitis, causing honeycomb destruction of the hair shaft by T. schoenleinii with yellow cup-shaped crusts (scutula).
What is Kerion?
An abscess caused by a fungal infection.
Organisms include M. canis, T. verrucosum, T. mentagrophytes, and T. tonsurans.
What is Majocchi granuloma?
A deep and persistent suppurative and granulomatous folliculitis caused by a fungal infection.
Organism: T. rubrum.
What is Tinea corporis?
A superficial fungal infection characterized by a ring-shaped lesion.
Organisms include T. rubrum and T. mentagrophytes.
What is Tinea imbricata?
A superficial fungal infection generally caused by T. concentricum.
What is Tinea barbae?
A fungal infection of the beard and moustache region.
Organisms include T. verrucosum (cattle), T. mentagrophytes, M. canis, and T. tonsurans.
What is Tinea faciei?
A fungal infection of the face, usually caused by zoophilic species.
Organisms include M. canis, T. mentagrophytes, and T. rubrum.
What is Tinea cruris?
A fungal infection of the inner thigh.
Organisms include T. rubrum, E. floccosum, and T. interdigitale.
What is Tinea pedis?
A fungal infection of the feet.
Organisms include T. rubrum, E. floccosum, and T. interdigitale. Bullous type caused by T. mentagrophytes.
What is Tinea manuum?
An infection of the palm and interdigital spaces.
Organisms include T. rubrum, T. mentagrophytes, and E. floccosum. Often presents as non-inflammatory and unilateral ‘two feet one hand syndrome’.
What is Onychomycosis?
A fungal infection of the nails.
Distal type caused by T. rubrum, T. interdigitale, and E. floccosum; proximal type by T. rubrum (increased risk of HIV); dark onychomycosis by Scytalidium spp; white superficial onychomycosis by Fusarium spp & Scopulariopsis brevicaulis.
What are the causes of nodules on the hair shaft?
Black Piedra
Whire Piedra
Nits
Trichomycosis
Tirchorrhexis nodosa
Hair cast
Describe DDx
Single, sharply demarcated brown macule on the finger
Dx: Tinea Nigra
DDx: Cafe au lait macule
Describe and DDx?
Hyperpigmented macules and patches with fine scale on the trunk
Dx: Pit Versicolour
Malassezia appearance on microscopy?
Spagetti and meatballs
Yeast and short hyphal forms in the stratum corneum highlighted by a PAS stain
White piedra - arthocondidia and blastoconidia
Describe
What are the three patterns of hair invasion by dermatophytes?
What infectious agents might cause sporotrchoid spread?
Sporothrix are dimorphic fungi - whether a hyphae or yeast forms depends on the temperature
T
What is the difference between a hyphae and a yeast?
Yeasts are microscopic fungi consisting of solitary cells that reproduce by budding.
Molds, in contrast, occur in long filaments known as hyphae, which grow by apical extension
Sporothrix cultures rapidly at 25 degrees
T
What is the key ddx for sporotrichoid spread?
Sporothrix spp (inc schenckii)
Mycobacterium marinum
Topical treatment is often effective for sporothrix infection
F - rarely effective
Potassium Iodide is first line treatment for sporothrix
False - Itraconazole 100- 200 mg daily for 3 - 6 months
List the common Microsporum dermatophytes
Canis
Ferrugineum
Gypseum
What is the Epidermophyton dermatophyte?
Floccosum
What is the most common dermatophyte?
Trichophyton Rubrum
Which dermatophyte emerged in india with terbinafine drug resistance?
Trichophyton Indotineae
RF for tinea infection
SES
Occupation
Air conditioning
Use of footwear
Pets
RF for tinea capitus
Household exposure to tinea capitus or pedis
Environmental factors - contanimated hats / hair brushes etc
Down syndrome (tinea unguium)
M > F
Immunodeficency
Key features of Tinea Corporis
Dermatophyte infection of the trunk
Most common org: T rubrum and T mentagrophytes
Extent of inflammation depends on the causative organism and immune response
Clinical features of tinea corporis
Extent of inflammation depends on cauasative organism and host immue response
Arcuate, circinate, concentric and oval lesions
Central clearing
Leading scaly edge +/- pustules
Clinical variants of tinea corporis
Profunda
Nodular
Perifolliculitis
Majocchi granuloma
Dermatophyte mimic of erythmea gyratum repens?
Tinea imbricata
Concentric annular rings resembling erythema gyratum repens
Key features of Tinea Cruris
Dermatophyte infection of the groin / inner thighs
Common Org: Epidermophyton Floccosum, T. Rubrum and T mentagrophytes
M > F
RF: obesity, excessive perspiration, tinea pedis or onchychomycosis
What is Tinea Manuum?
Dermatophyte infection on the palm and interdigital spaces
Key organisms for Tinea Manuum?
T. Rubrum
T. Mentagrophytes
E. Floccosum
Key features and Dx?
Diffuse scaling of the palm of one hand, accentuation of the creases
Minimal inflammation
Dx: Tinea Manuum
Tinea Barbae key features
Dermatophyte infection of the beard
Normally from zoonotic dermatophytes - T. mentagrophytes and T. Verrucosum
Most common cause of tinea capitus
T. Tonsurans
Endothrix organisms
Trichophyton Tonsurans
Trichophyton Violaceum
Trichophyton gourvilli
Ectothrix Organisms
Microsporum Canis
Microsporum Audouinii
Microsporum Ferrugineum
Microsporum Gypseum
Dermoscopic clues to tinea capitus?
Alopecia
Corckscrew
Comma hairs
what is favus?
A pattern of hair invasion of dermatophytes
Caused by Trichophyton Schoenleinii
Hyphea and air spaces are seen within the hair shaft
Woodlight is blue - white
What are the major types of tinea pedis?
Moccasin
Interdigital
Inflammatory
Ulcerative
What is moccasin?
A clinical subtype of tinea pedis
Characterised by: diffuse hyperkeratosis, erythema, scaling and fissures
Org: Trichophyton rubrum and Epidermophyton floccosum
Rx: topical + urea / lactic acid
Non0dermatophyte mimics = neoscytalidium hyalinum
What is tinea interdigital?
A subtype of tinea pedis (most common)
Characterised by erythema, scale, fissures and maceration in the web spaces
Org: Trychophyton interdigitale, trichophyton rubrum, E floccosum
What organism causes Inflammatory tinea pedis?
Trichophyton Mentagrophytes
Indicators of more severe nail disease for onychomycosis?
What are the complications for tinea capitus?
Secondary bacterial skin infection, whcih can lead to systemic bacterial infection
○ Common organisms include MSSA, MRSA, Group A Strep
Alopecia ○ This is often scarring and permanent
Spread of the tinea to other body sites
○ Tinea corporis / tinea facei etc
Spread of the tinea to other individuals
○ Anthophilic spread
Autoeczematisation (ID reaction)
What are the dermoscopy findings in tinea capitus?
Describe your findings
DDx of tinea capitus?
Alopecia Areata
Focal Psoraisis
Trichotilimania
Seborrhoeic dermatitis
Bacterial folliculitis
Disecting cellulitis of the scalp
What are the clinical features of onychomycosis?
Nail discoloration,
Subungual hyperkeratosis,
Onycholysis,
Splitting of the nail plate,
Nail plate destruction
What are the complicaitons of onychomycosis?
Pain,
Transmission of fungal infection to other body sites,
Transmission of fungal infection to other people
Secondary bacterial infection
ID reaction
Loss of the nail
Psychological distress
What are some cause of onychomycosis?
Trichophyton Rubrum
Trichophyton Mentagrophytes
Epidermophyton floccosum
Microsporum Canis
Candida spp.
Fusarium,
Aspergillus,
DDx on onychomycosis?
Psoriasis
Eczema
Trauma
Lichen Planus
Yellow nail syndrome
Paronychia congenita
