Fungal disease Flashcards
1
Q
What are the 3 genera of dermatophytes?
A
microsporum, trichophyton, epidermophyton
2
Q
What are the two large subgroups between each of the 3 genera of dermatophytes?
A
Microconidia and macroconidia
3
Q
What are conidia?
A
An asexual spore of a fungus
4
Q
What is the importance of the conidia for the different dermatophytes?
A
For different dermatophytes, the phenotype of either the microconidia or the macroconidia can be dx.
5
Q
What is the diagnostic appearance of Microsporum dermatophytes?
A
Macroconidia are dx, rough-walled, often spindle-shaped, thick cell wall and multi-celled
6
Q
What is the diagnostic appearance of trichophyton?
A
Micoconidia is diagnostic: smooth-walled, one-celled. The macroconidia are not distinctive but are often cylindric to clavate
7
Q
Which type of dermatophyte doesn’t have microconidia?
A
Epidermophyton only have macroconidia
8
Q
What is the appearance of the macroconidia in epidermophyton?
A
smooth-walled, club-shaped, intermediate cell wall thickness, mutli-celled, occur solitary or in clusters.
9
Q
What is the difference between anthropophilic, zoophilic, and geophilic?
A
anthropophilic: restricted to humans Zoophilic: primarily affects animals Geophilic: found in soil
10
Q
What is the different clinical responses between anthropophilic, zoophilic, and geophilic fungi?
A
Anthropophilic: chronic, mild inflammatory response Zoophilic: causes massive inflammatory reponse in humans Geophilic: Causes severe inflammatory response and scarring in humans
11
Q
What species of dermatophytes are anthropophilic?
A
all trichophyton spp (except T. mentagrophytes and T. verrucosum), E. floccosum, M. audouinii, and M. ferrugineum
12
Q
What dermatophyte species are zoophilic?
A
M. Canis (cats and dogs), M. nanum (pigs), t. Verrucosum (Cattle), and T. mentagrophytes (rodents)
13
Q
What dermatophyte species are geophilic?
A
M. gypseum
14
Q
Histology of dermatophyte infection?
A
Septate hyphae in stratum corneum or nail plate, brisk dermal inflammation (vs minimal in tinea versicolor) +/- neutrophilic micro-abscesses in epidermis or corneum/nail plate
15
Q
What color do dermatophytes show up as in PAS or GMS?
A
PAS = red GMS = Black
16
Q
What is chlorazol black?
A
Chitin stain, hyphae will be green
17
Q
Describe microsporum gypseum?
A
Geophilic, infrequent human pathogen -Ectothrix -cinammon color, granular colony on culture -Grows rapidly (5 days) -Macroconidia: thin walled, founded ends < 6 septa -+ polished rice growth
18
Q
Describe microsporum canis?
A
zoophilic #1 cause of tinea capitis worldwide, common cause of tinea corporis -macroconidia: thick-walled; pointed ends; >6 septae -Growth on polished rice -Culture: canary yellow reverse
19
Q
Most common organism to cause tinea capitis worldwide?
A
Microsporum canis
20
Q
Most common cause of transmission of Microsporum canis?
A
Kittens to humans
21
Q
What type of infection does microsporum canis cause?
A
Inflammatory infection
22
Q
Is M. Canis an endothrix or ectothrix?
A
Ectothrix
23
Q
Is M. audouinii an endothrix or ectothrix?
A
Ectothrix
24
Q
What does M. audouinii cause?
A
A formerly common cause of tinea capitis
25
Characteristics of M. audouinii?
Anthropophilic, pectinate hyphae, culture: salmon reverse color, widely spaced radial grooves, polished rice growth
26
What color does M. Audouinii glow with woods lamp?
Yellow-green
27
What color does M. canis glow with woods lamp?
Yellow-green
28
Describe trichophyton rubrum?
Anthropophilic, microconidia have a teardrop or peg-shaped "birds of a wife" appearance -Culture: reverse red color, white cottony surface
29
What is the most common dermatophyte worldwide?
T. rubrum
30
Clinical of T. rubrum?
Generally not inflammatory can cause Majocchi's granuloma and can perforate the hair
31
Describe T. mentagrophytes?
Can be Zoophilic (var mentags) which is inflammatory infection w/ granular colony or anthropophilic (var interdigitale) which is non-inflammatory, cottony colony -Spiral hyphae, microconidia -In the zoophilic form microconidia abundant in round clusters -In anthropophilic form resembles T. rubrum \*\*Positive urease test and hair penetration test\*\* -No pigment production on rice extract-glucose agar
32
Describe T tonsurans?
Anthropophilic -black dot tinea capitis, non-fluorescent -large spore endothrix -microconidia are balon shaped, various sizes -Culture: yellow to cream surface, w/ feathery periphery. -Requires thiamine to grow
33
Is T. tonsurans endothrix or ectothrix?
endothrix
34
Is T. violaceum endothrix or ectothrix?
endothrix
35
What organism causes black dot tinea capitis?
T. violaceum
36
Describe T. violaceum?
Anthrophilic -Culture: dark violet color, cerebiform pattern, reverse also purple -thiamine growth requirement
37
Describe T. schoenleinii?
Anthropophilic -Dull, blue-green fluorescent tinea capitis -Air canals within hair -Knobby antler like hyphae, favic chandeliers -Culture: tan color; cerebriform -No growth requirements
38
Woods lamp findings from tinea capitis from T. schoenleinii?
Dull, blue-green fluorescence
39
What organism causes favus?
T. schoenleinii
40
What is favus?
Most commonly occurs as tinea capitis but can occur elsewhere. It starts perifollicular but then it turns to thick yellow adherent scales (scutula). Most commonly caused from T. Schoenleinii
41
Describe T verrucosum?
Zoophilic (cattle/horses), -rat tail macroconidia -Culture: tan to white, heaped up/folded -Inositol and thiamine growth requirement
42
Is T verrucosum ectothrix or endothrix?
Ectothrix
43
What dz does T verrucosum cause?
Inflammatory tinea barbae, kerion-like tinea barbae, corporis, and capitis
44
Describe E. floccosum
Anthropophilic -culture: flat feathery colonies, yellow-brown reverse -Macroconidia- club-shaped in clusters like beavertail
45
What disease is caused by E. floccosum?
Tinea cruris, tinea pedis, no hair invasion
46
What areas are not affected by tinea corporis?
Hands, feet, groin, face, scalp
47
Predisposing factors for tinea corporis?
DM, HIV, immunosuppression, animal/human contact, chronic scalp/foot/hand reservoir
48
What dermatophytes cause tinea corporis?
Microsporum, trichophyton, epidermophyton
49
What are the most common causes of tinea corporis?
T rubrum, T. mentagrophytes, M. canis
50
Clinical of tinea corporis?
Annular, erythematous, scaling plaques, often with an active border and central clearing. This annular shape has led to the lay-term "ringworm” Papules, vesicles, and crusting may develop in the active border
51
When should oral tx for tinea corporis be considered?
Widespread, severe, granulomatous, or verrucous lesions
52
Is the yield of KOH decreased or improved w/ tinea incognito?
Improved.
53
Presentation of tinea incognito?
Patches or papules and plaques with less erythema and more subtle scale
54
What is tinea profunda?
Excessive inflammatory response to the dermatophyte, like kerion in the scalp.
55
What is tinea imbricata?
Dermatophytosis caused by the anthropophilic dermatophyte T. concentricum. It causes chronic infections in an equatorial band encompassing the South Pacific, Asia, and Central and South America. The clinical presentation consists of concentric annular rings resembling erythema gyratum repens (but with less redness/erythema often)
56
What is nodular perifolliculitis?
Usually caused by T. rubrum. -follicular papulopustules or granulomatous nodules that result from a deep dermatophyte folliculitis with disruption of the follicular wall -Most common: women who have tinea pedis or onychomycosis and shave their legs, and it can also occur in the setting of immunosuppression -The lesions may be extensive or even vegetating, and a prolonged granulomatous reaction can develop
57
What is Majocchi's granuloma?
Erythematous papules/nodules around hair follicles, particularly lower legs (may arise from tinea pedis) -Dermatophyte grows down hair follicles producing a folliculitis
58
Predisposing factors for Majocchi's granuloma?
- shaving legs (women), or topical steroid use
59
Most common pathogens to cause Majocchi's granuloma?
T. Rubrum (most common) T. mentagrophytes
60
Treatment for Majocchi's granuloma?
Systemic antifungals
61
Important distribution finding in tinea cruris to distinguish from candida?
Spares the scrotum
62
Most common pathogens causing tinea cruris?
Tinea rubrum\> epidermophyton floccosum, Tinea interdigitale, Tinea mentagrophytes
63
What is tinea manuum?
Scaly, dry, hyperkeratotic lesions of palmar surfaces, often involves both feet and one hand.
64
Treatment for tinea manuum?
Need to use systemic usually, topicals rarely effective
65
Most common pathogens of Tinea manuum?
T. Rubrum, T. mentags, E. floccosum
66
Most common pathogens of Tinea Barbae?
T. mentagrophytes, T. verruscosum, T. rubrum, T. sonsurans
67
Clinical of tinea barbae?
Typically unilateral on face/neck -Papules/pustules
68
What pathogens usually cause tinea faciei?
Usually zoophilic species -T mentag, M. canis \> T.rubrum
69
Presentation of tinea faciei?
Scaling present in \<2/3 cases, erythematous follicular based papules, often in an annular distribution. -Itches and burns, often worse after sun exposure -most common in kids
70
Treatment of tinea faciei?
Systemic antifungals
71
What is the #1 cause of tinea capitis in the US?
Trichophyton tonsurans (less inflammatory than M. canis)
72
What is the #1 cause of tinea capitis in the world?
Microsporum canis (more inflammatory)
73
Clinical of tinea capitis?
Circular scaling patches +/- pustules +/- LAD May have black dots from broken hairs in endothrix infxn -Disease primarily of childhood, increased in black/males
74
Treatment for tinea capitis?
systemic antifungal
75
What antifungal is first line for kids with tinea capitis?
Griseofulvin
76
Which dermatophytes are ectothrix?
M. canis, M. audouinii, M. ferrugineum, M. distortum, M. gypseum, T. rubrum (rarely) -notice microsporum mostly ectothrix and trychophyton mostly endothrix
77
Which dermatophytes are endothrix?
T. tonsurans, T. violaceum, T. soudanense, T. gourvilli, T. yaoundei, T. rubrum (rarely) -notice microsporum mostly ectothrix and trychophyton mostly endothrix
78
Which dermatophytes cause yellow fluorescence with woods lamp?
Mostly the microsporum (ectothrix) -M. canis, M. audouinii, M. ferrugineum, M. distortum
79
What is the substance that fluoresces w/ Wood's lamp in ectothrix species?
Pteridine
80
What is kerion?
Boggy inflamed nodule/abscess w/ pustules and possible LAD which may lead to scarring
81
Most common organisms to cause kerion?
M. canis, T. verrucosum, T. mentagrophytes, T. Tonsurans
82
What is pityriasis amiantacea and what can help distinguish it from tinea capitis?
Usually, thick yellow-white overlapping scales underlying skin normal, red or scaly. Causes can be psoriasis, LSC, seb derm, rarely tinea. -Usually partial scalp involvement, rarely whole scalp. -Some hair loss common... but regrows
83
Most common pathogens associated with tinea pedis?
T. rubrum \>E. floccosum (moccasin), T. interdigitale (interdigital)
84
Most common pathogen associated with vesicular/bullous tinea?
T. mentagrophytes
85
Clinical of tinea pedis?
Erythema w/ scale, especially b/w toes (maceration) and sides of feet
86
Organisms that cause onychomycosis (distal/lateral subungal)
This is most common... starts laterally but can invade laterally. -T. rubrum, T. interdigitale, E. floccosum -Also, non-dermatophytes: scopulariopsis brevicaulis, aspergillus
87
Most common organism causing proximal sunbungal onychomycosis?
Least common, but common in HIV dz -Invades the proximal nail fold then nail plate -T. rubrum
88
What can proximal subungal onychomycosis be associated with?
HIV/immunosupression
89
Where does superficial white nail occur?
Only in the toenails, never fingernails -infection of only the surface of the nail plate
90
What organism is most commonly associated with white nail?
T mentagrophytes (adults) vs T. rubrum in children, non-dermatophyte molds too
91
Which antifungal is more effective against T. tonsurans?
Terbinafine
92
Which antifungal is more effective against Microsporum?
Griseofulvin
93
What are the 4 non-inflammatory superficial mycoses? (non-dermatophytes)
Pityriasis versicolor, white piedra, black piedra, tinea nigra
94
Most common organisms to cause pityriasis versicolor (tinea versicolor)?
Malassezia globose, Malassezia furfur, M sympodialis (neonatal cephalic pustulosis)
95
What do the different states of the Malassezia tell us about the clinical scenario?
Yeast form is normal skin flora, the filamentous hyphal form is seen in disease states
96
What is required to grow Malassezia species in culture?
Olive oil
97
Most common species in seb derm?
M. restricta
98
What leads to the clinical presentation of hypopigmented plaques?
Azelaic acid from the yeast block melanin
99
Pathogenesis of pityriasis versicolor?
Overgrowth of normal flora --\> warmth and humidity in right host are key
100
What topical or oral medications are best for pityriasis versicolor?
Azole-antifungals
101
Clinical of pityriasis versicolor?
hyper- or hypopigmented finely scaling circular/oval macules/patches in sebaceous distribution (scalp, face, neck, upper chest, and upper back)
102
What organism causes black and white piedra?
Black: piedra hortae White: trichosporon asahii, T. beigelii, t. ovoides, T. inkin and T. cutaneum
103
Histology of piedra?
Black or white concretions along hair (encircle hair, unlike the sac-like appearance of lice) White Piedra with soft mobile nodules; black Piedra with hard nonmobile nodules
104
Clinical of piedra?
Asymptomatic hair breakage on scalp, axillary, and pubic region
105
Treatment for piedra?
Hair shaving/cutting and antifungal shampoos; systemic antifungals recalcitrant
106
What is trichosporanosis?
Dissemination of trichosporon from white piedra can occur in immunocompromised hosts --\> can lead to purpuric or necrotic cutaneous papules and nodules. (T. Asahii)
107
Clinical distribution for white vs black piedra?
White piedra= facial, axillary, genital hair \> scalp Black piedra= scalp\>rarely beard/genitals
108
The difference in texture between white and black piedra?
White piedra: soft and loose on the hair Black piedra: hard and firm on hair
109
What organism generally causes tinea nigra?
Hortaea werneckii
110
Microscopy of tinea nigra?
dark brown septate hyphae w/ budding yeast in thickened stratum corneum
111
Clinical of tinea nigra?
dark-brown/black macule or small patch on palms/soles, limited to stratum corneum
112
Treatment of tinea nigra?
azole creams, Whitfield’s ointment (6% benzoic acid, 3% sal acid ), oral terbinafine if recalcitrant
113
What is the pathogen that causes protothecosis?
Prototheca wickerhamii (not a fungus but algae)
114
Pathogenesis of protothecosis?
Introduced into skin via trauma in contaminated water
115
Histology of protothecosis?
Distinctive morula like appearance on H&E.
116
Clinical of protothecosis?
Nodules/ulcers/plaques and/or olecranon bursitis
117
Treatment for protothecosis?
Excision and systemic antifungals (e.g., amphotericin B)
118
Clinical of chromoblastomycosis?
wks-mos after inoculation, pruritic papules/nodules expand and become verrucous w/ black dots; does not invade muscle or bone; chronic lesion can turn to SCC
119
Histology of chromoblastomycosis?
Pseudoepitheliomatous hyperplasia, granulomatous dermal inflammation w/ medlar bodies (pigmented muriform cells, “copper pennies”)
120
Treatment of chromoblastomycosis?
Itraconazole, 5-flucytosine, among other antifungals; surgical excision for small lesions
121
What are the two major types of mycetoma?
Eumycetoma (fungus) and actinomycetoma (bacteria)
122
Most common eumycetoma species?
Madurella spp. Pseudallescheria boydii (MC) exophiala jeanselmei Acremonium spp.
123
Most common actinomycetoma species?
Nocardia brasiliensis (#1) N. asteroids (both have white grains) actinomadura madurae (A. pelletieri=red grains) A.madurae=cream or pink grains) Streptomyces somaliensis (yellow-brown grains)
124
Clinical of mycetoma?
Slow progression of tumors w/ sinus tracts draining grains, which are fungal or bacterial aggregates; MC on feet/lower legs; long standing lesions--\> bone and visceral involvement Black grains only seen in eumycetoma and red grains only seen in actinomycetoma (specifically A.pelletieri); other colored grains seen in both types
125
Histology of mycetoma?
granulomatous reaction w/ grains; serologic testing used bc of culture difficulty
126
Treatment of mycetoma?
Euycotic mycetoma: surgical excision, several months azoles Actinomycotic mycetoma: sulfonamides and other antibiotics.
127
What organisms cause sporotrichosis?
Sporothrix schenckii (dimorphic)
128
What is the microscopy of sporotrichosis lesions?
Usually not well-visualized with stains; granulomatous inflammation w/ plasma cells and asteroid corpuscles (Splendore-Hoeppli phenomenon); organisms are cigar-shaped budding yeast
129
Pathogenesis of sporotrichosis?
Traumatic inoculation from soil via plant thorns, wood splinters, and sphagnum moss\>\>cats/rodents/armadillo bites; inhalation of spores
130
Clinical of sporotrichosis?
Multiple ascending ulcerated nodules or subsequent abscesses, most frequently in gardeners, agriculture/farm workers, and veterinarians -May lead to erythema nodosum
131
Treatment for sporotrichosis?
Obtain fungal culture (difficult to find in tissue samples), itraconazole (TOC), SSKI, and amphotericin B in disseminated dz
132
DDx for sporotrichoid spread?
NoSALT Nocardia Sporotrichosis Atypical mycobacteria Leishmaniasis Tularemia
133
What is the most common cause of lymphocutaneous patterned disease?
Atypical mycobacterial, especially M. marinum, then sporotrichosis -nocardia, other bacteria or less common,
134
What organism causes lobomycosis?
Lacazia (loboa loboi)
135
Where is lobomycosis seen?
It infects freshwater dolphins in south american rivers -- infects those that come in contact
136
Clinical of lobomycosis?
keloid like verrucous fibrotic nodules that can ulcerate; men\>\> women; rural areas
137
Treatment for lobomycosis?
Surgical excision
138
Microscopy of lobomycosis?
Thick-walled yeast w/ tubular connections b/w cells- “pop bead” or “chain of coins” appearance
139
What are the main 4 systemic (dimorphic) mycoses?
Histoplasmosis, blastomycosis, coccidiomycosis, paracoccidiomycosis
140
Where is histoplasmosis seen in the US?
Ohio+ Mississippi river valleys
141
Microscopy of histoplasmosis?
Tuberculoid granuloma w/ intracellular 2-4 micrometer yeast in histiocytes (looks like leishmaniasis, but see yeast have surrounding halo and are more evenly distributed throughout histiocyte cytoplasm; lacks “marquee sign” and kinetoplast)
142
Pathogenesis of histoplasmosis?
Inhalation (esp. bird and bat feces) w/ hematogenous spread (can go to liver, spleen, bone marrow, brain; skin involvement more common in HIV, often p/w umbilicated or “molluscoid” papules)
143
Clinical of histoplasmosis?
primary cutaneous chancre w/ lymphangitis and lymphadenitis (rare); More commonly, secondary cutaneous molluscoid nodules, cellulitis, ulcers, panniculitis, and oral lesions -Pulmonary manifestations=MC presentation
144
Diagnosis of Histoplasmosis?
Culture is gold standard (also urinary ELISA or PCR)
145
Treatment for histoplasmosis?
Itraconazole (mild-mod dz) or amphotericin B (severe dz)
146
Geographic areas affected by blastomycosis?
Southeastern U.S, Great Lakes, KY, Miss, Chicago
147
Histology of blastomycosis?
Pseudoepitheliomatous hyperplasia, granulomatous dermal inflammation w/ unipolar budding yeast (8-18micrometers) (Broad-based buds)
148
Pathogenesis of blastomycosis infection?
Inhalation w/ subsequent hematogenous spread to skin (\>75% of cases), bones, and GU tract (e.g. prostate, spleen, liver, brain)
149
Clinical of blastomycosis?
-Primary cutaneous form (rare) presents w/ lymphangitis and lymphadenitis at injury site -Secondary cutaneous form (more common); due to hematogenous dissemination from lungs to skin), presents w/ verrucous nodules, abscesses and ulcers (can occur orally as well) -Pulmonary manifestations: most common presentation
150
Diagnosis of blastomycosis?
KOH of purulent exudate, DNA probe assay, (culture is difficult), serology
151
Treatment of blastomycosis?
Polyene and azole antifungals (Itraconazole 200-400 mg/day for 6 mos) and amphotericin B (Severe disease)
152
Geography of coccidiomycosis?
Desert SW United States (esp. Central Valley/San Joaquin Valley, California), Mexico, and Central/South America
153
Histology of coccidiomycosis?
Large (up to 100 micrometer) spherules containing endospores; also has PEH and granulomatous inflammation
154
Pathogenesis of coccidiomycosis?
Inhalation w/ hematogenous spread to skin (as well as CNS and bone); very rarely primary cutaneous infection
155
Clinical of coccidiomycosis?
Verrucous nodules/ papules, pustules, abscesses, or ulcerative lesions Pulmonary manifestations= MC presentation
156
Treatment for coccidiomycosis?
limited and cutaneous: itraconazole Severe: amphotericin B Meningeal: amphotericin B and fluconazole
157
Geography of paracoccidioidomycosis?
Southern US, Mexico, and Central/South America
158
Microscopy of paracoccidioidomycosis?
Pseudoepitheliomatous hyperplasia, granulomatous dermal inflammation w/ multipolar budding yeast (mariner’s wheel)
159
Pathogenesis of paracoccidioidomycosis?
Inhalation of infected soil (can disseminated to skin, liver, adrenal glands, LN, GI tract, and spleen); rarely may arise from direct inoculation in skin
160
Clinical of paracoccidioidomycosis?
-Granulomatous ulcerative oropharyngeal and perioral involvement in 70% of adults; cutaneous lesions can be contiguous, hematogenous, or via inoculation -Clinical appearance of ulcers w/ infiltrated borders and hemorrhagic dots, and associated LAD (can be massive) -Men\>\>\>women -Pulm disease (granulomatous and chronic) most common presentation
161
Most common candida species in localized and generalized infections?
Albicans
162
Candida species commonly seen in chronic paronychia?
C. parapsiosis
163
What canidida species can be seen in HIV patients w/ oropharyngeal candidiasis?
C. Dubliniensis
164
Diagnosis of superficial candidiasis?
KOH w/ budding yeasts w/ pseudohyphae -If concern for systemic w/ skin lesions --\> bx showing organisms in dermis and blood vessels; stain with PAS or methenamine silver -Culture of skin lesions -Blood cx often negative
165
Clinical of median rhomboid glossitis?
Central smooth erythema of tongue, 2/2 candida. Can get loss of lingual papillae giving it the look of atrophy
166
Clinical of candida intertrigo?
Beefy red color + satellite pustules +/- erosions. Compare with irritant intertrigo w/o pustules and erosions, not as beefy red
167
What is the #1 cause of infectious balanitis?
Candida
168
Clinical of candidal balanitis?
Papules, pustules on glans, may extend to the prepuce
169
Cause of black hairy tongue?
Altered normal flora --\> overgrowth of bacteria and fungi Papillary hypertrophy and abnormal desquamation involved.
170
Treatment for black hairy tongue?
Physical debridement and good hygiene
171
Differentiation of tinea cruris and candidal involvement?
Scrotum often involved in candidal form. You can also see satellite pustules and subcorneal pustules. \*\*Look for fold involvement. Irritant will often spare the fold whereas candida involves the folds.
172
What do you can candidiasis between the web toe spaces?
Erosion interdigitalis blastomycetica (often third or 4th web space of toes or fingers)
173
Clinical of congenital candidiasis?
Pink maculopapular eruption progressing to vesicles/pustules with desquamation
174
Treatment for congenital candidiasis?
topicals +/- systemic
175
Diagnosis of congenital candidiasis?
KOH or gram stain of pustular or vesicular contents
176
What is the source of most systemic candidiasis?
Usually starts in GI tract; 10% of bloodstream infections
177
Clinical of deep-seated or systemic candidiasis?
See scattered papules/nodules, occ. Hemorrhagic and ecthyma gangrenosum-like
178
Which Candida species have lower sensitivities to azoles?
Glabrata and Krusei
179
Geography of cryptococcosis?
In bird droppings, especially pigeons and bark/fruit of tropical trees. Cryptococcus neoformans is ubiquitous, Cryptococcus gattii is tropical/sub-tropical
180
Histology of cryptococcus?
Single-cells sphere w/ double cell wall and thick capsules (“halo” appearance), may have one or more buds (blastoconidia); a collection of organism look like soap bubbles Stains: India ink, PAS, mucicarmine, GMS, Fontana-Masson
181
Pathogenesis of cryptococcosis?
Inhalation--\> lungs (Primary pulm infection, usually mild) hematogenous spread (CNS, bones, skin); can also arise from primary inoculation of skin (rare) -More common in immunosuppressed (esp HIV/AIDS, but also a/w sarcoidosis and pregnancy)
182
What is the virulence factor for cryptococcus?
Glucuronoxylomannan polysaccharide capsule
183
Clinical of cryptococcosis in the skin?
Papules/ nodules (often molluscum-like) that can be umbilicated and/or ulcerated, and prefer head/neck, mouth, nose -Patients w/ secondary cutaneous lesions have a high mortality rate -Nodular lymphangitic syndrome- a nodule at the inoculation site, nodular lymphangitis, and adenopathy -Meningoencephalitis is a serious and common manifestation
184
Treatment for cryptococcosis?
-oral fluconazole, -CNS: amphotericin B and Flucytosine
185
Most common organisms to cause aspergillosis?
Aspergillus fumigatus (most common), Aspergillus Flavus (2nd most common), Aspergillus niger (can lead to otomycosis)
186
Histology of aspergillus sp?
Septate hyphae w/45-degree angle branching?
187
Pathogenesis of aspergillosis?
Can be primary cutaneous disease (MC A. Flavus) via direct inoculation (e.g., IV catheter, trauma sites, burn sites, and disturbed skin under dressings) vs secondary cutaneous disease (MC A. fumigatus; more common, typically in immunosuppressed, esp. neutropenia) via inhalation--\>pulm aspergillosis --\>disseminated disease Both can--\> hematogenous spread w/ tendency for vascular invasion causing thrombus and necrosis
188
Clinical of aspergillosis in the skin?
Six clinical forms including erythematous edematous plaques, nodules w/ necrotic centers, hemorrhagic bullae, and necrotic ulcers can involve CNS, heart, kidneys, bone, GI tract
189
What species of aspergillus most commonly causes primary cutaneous disease?
Aspergillus flavus (hemorragic bullae or mulluscum lesions)
190
Treatment for aspergillosis?
Amphotericin B (esp. w/ invasive) or voriconazole (in combo with caspofungin)
191
What species of aspergillus is the most common to cause disseminated dz w/ cutaneous findings?
Aspergillus fumigatus
192
What organisms cause hyalohyphomycosis?
Penicillium, Paecilomyces, and Fusarium
193
Histology of Fusarium infections?
45 degree angle branching, similar to Aspergillus
194
Pathogenesis of Fusarium infections?
More common in immunosuppressed; severe burns \*\*Most common fungus cultured in burn patients\*\* -Cutaneous disease via direct inoculation and hematogenous spread w/ tendency for vascular invasion causing thrombus/necrosis
195
What is the most common fungus cultured from burn patients?
Fusarium
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Clinical of Fusarium infections?
erythematous; edematous plaques more common than subq nodules (purpuric or ecthyma gangrenosum-like); panniculitis
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What organism causes penicilliosis?
Penicillium marneffei is the only pathogenic species
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Where does penicilliosis occur?
SE Asia
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Histology of penicilliosis?
Intracellular parasitic phase in macrophage
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Pathogenesis of penicilliosis?
Acquired by inhalation or possibly abrasions; bamboo rat exposure may be RF
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Clinical of penicilliosis?
Similar to histoplasmosis: fever, wt loss, LAD, cough, and hepatosplenomegaly -Cutaneous manifestations: papules w/ central necrosis and molluscum like lesions; face, arms, and trunk are most common sites
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Treatment of penicilliosis?
Polyenes (amphotericin B and terbinafine) and azole antifungals
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Why are the 2 orders of organisms that can cause zygomycosis (mucormycosis) and what organisms are in each?
Order Mucorales: Rhizopus, Mucor, Absidia, and others = systemic and cutaneous dz Order Entomophthorales: conidiobolus coronatus = rare, chronic, cutaneous and subcutaneous infection in the tropics
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Microscopy of mucormycosis?
Broad ribbon-like nonseptate hyphae w/ 90 degree angle branching, angioinvasive w/ thrombosis
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Pathogenesis of mucormycosis?
Most commonly enter via respiratory tract (though there are other portals of entry like skin), and can invade blood vessels--\>thrombosis/infarction/necrosis. More common in immunosuppressed, but also nonimmunodeficient (e.g., severe diabetes and severe burns)
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Clinical of zygomycosis (mucormycosis)?
subtypes include: rhinocerebral (MC subtype; usually in diabetes pt w/ DKA), pulmonary, GI, primary cutaneous (from surgery, catheterization, or burns), and disseminated -All forms are rapidly progressing and commonly fatal -Cutaneous lesions (can be primary or secondary) typically indurated, necrotic black plaque/eschars most commonly seen on the face (nasal and oral in rhinocerebral type) -Rhinocerebral type may have epistaxis, facial pain, periorbital cellulitis, proptosis, and loss of EOM movement (secondary to cranial nerve palsies)
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Treatment for zygomycosis (mucormycosis)?
Aggressive surgical resection of all necrotic areas (crucial to survival of patient) and amphotericin B (lipid formulation); posaconazole may be alternative
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What organisms cause phaeohyphomycosis?
Dematiaceous (pigented) fungi: Exophiala jeanselmei (most common cause), Wangiella dermatitidis, Alternaria bipolaris, Phialophora, Curvularia
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What areas does phaeohyphomycosis occur?
Tropics and temperate zones
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Clinical of phaeohyphomycosis?
Subcutaneous, potentially draining, inflammatory abscess or cyst. It can mimic baker cysts or other cysts.
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Microscopy of phaeohyphomycosis?
Cyst composed of macrophages and short hyphae, with a fibrous capsule -Hyphae are pigmented/brown, and stain + w/ Fontana-Masson
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Treatment of phaeohyphomycosis?
Excision and intraconazole
