Fungal infections Dan Flashcards
T/F
Interdigitial tinea pedis is common in young children
False
Rare
think of psoriasis
How can fungal disease be broadly classified in derm?
Superficial mycoses - involve SC, hair and nails
Subcutaneous mycoses – involve dermis or subcutis
Systemic mycoses (less of a derm problem)
What are the main superficial mycoses?
Non-inflammatory group - Pit versic, Pit folliculitis - Tina nigra - Black or white piedra Inflammatory group - Dermatophytoses - Non-dermatophyte superficial mycoses - Candidoses
What are the main subcutaneous mycoses?
Sporotrichosis Cryptococcosis Chromoblastomycoses Phaeohyphomycoses Mycteoma
T/F
Yeasts form true hyphae
False
only fungus forms true hyphae - may or may not have septae (mark division between neighbouring cells)
Yeast can form pseudohyphae - due to incomplete budding they have constrictions which mimic septae of true hyphae
What organisms cause Pityriasis versicolour and Pityrosporum folliculitis?
Malassezia furfur (old name was pityrosporum ovale) or sometimes by M. globosa, sympodialis or restricta
T/F
The normal commensual amount of malasezzia spp on the skin can be detected by skin scraping and KOH prep
False
too few to pick up with scrape
alos mainly yeast (spore) form normally but in Pit versic get many Mycelial forms (hyphae)
T/F
Malsaezzia spp feed on sebum
True
lipophilic
so less common in kids but common in teens
What are risk factors for Pit versic?
humidity warm temps excess sweating oily skin (seborrhoea) poor nutrition immunodeficiency steroid use pregnancy
T/F
neonatal cephalic pustulosis is thought to be due to M. sympodialis
True
T/F
Seborrheoic dermatitis is thought to be triggerd by M. sympodialis
False
More assoc w/ M. furfur, globosa and restricta
T/F
Pityrosporum folliculitis is due to specific types of malasezzia (furfur and/or globosa) growing in the hair follicle in yeast form only, no hyphae, causing local inflammation
True
T/F
In kids pit versic often affects the face
True
T/F
bright yellow fluorescence can sometimes be seen on Wood’s lamp exam of pit versic
True
T/F
The papules of pityrosporum folliculitis often have a central white plug of pus
False
often have a central white plug of keratin
Who is at increased risk of of pityrosporum folliculitis?
young women Down’s syndrome immunosuppressed after antibiotics esp doxy Acne pts esp if given doxy
How is KOH prep performed?
Wipe slide with alco wipe and dry
Scrape scale onto slide
Add drop of 10-30% KOH
can counterstain with chlorazol black E
or gentle warming to ‘clear’
+/- Calcofluor white (fluoresces apple-green)
examine under brightfield microscope or under UV if calcofluor used
For pit folliculitis can express follicle contents onto slide and prepare as above to look for spores
Treatment ladder for pit versic/pit follliculitis
Advise;
o High rate of recurrence esp if risk factors continue
o Pigment changes take weeks-months to resolve
Address risk factors and treat if possible
e.g. keep cool, avoid sweating/shower ASAP after sweating, stop antibiotics/immune supression, improve nutrition
Antifungal shampoo/lotion best if widespread;
Ketoconazole shampoo (Nizoral) 2% daily for 10 days or leave on overnight and wash off then rpt after 7 days
Econazole lotion 1% (Pevaryl foaming lotion) nocte for 3 days leave on overnight then wash off + rpt at 1+3 months (3 days, 3 times)
2.5% Selenium sulphide shampoo (selsun gold) – leave on 20mins and wash off daily for 2 weeks – do not leave on overnight
50% propylene glycol in water (dries skin oils but often irritates) – apply with guaze twice a day for 2 weeks
If more localised can use cream; Any azole fine
May need to continue topical once a week as preventer
Systemics if resistant;
Fluconazole – 400mg single dose or 300mg/wk for 2-4 wks or 1-200mg/day for 3 weeks
Itraconazole – 200mg/day for 1 week (v expensive)
May need once monthly oral Rx to maintain remission – Flucon 300mg or Itra 200mg
If hyperseborhoea consider Acitrein/Iostretinoin or OSP or spiro in women but assess for hyperandrogenism first in women with hyperseborrhoea
What organism causes tinea nigra?
Hortaea Werneckii
T/F
Tinea nigra is a form of superficial phaeohyphomycosis
True
So is Black piedra - Piedraia hortae
Hortae means garden - in both cases organims are found in soil
What are the associations of tinea nigra?
No associations
occurs in kids>adults
T/F
Tinea nigra is rarely scaly
False
can have little scale, lots or even be thick and velvety
T/F
Tinea nigra most often occurs on ams and fingers
True
can be anywhere
T/F
abundant brown, branched hyphae are seen on KOH prep of tinea nigra
True
Hyphae have close septae and elongated budding cells
Whats the management of tinea nigra?
Can scrape off with scalpel blade Keratolytics or topical antifungals; Keratolytics – Whitfields’ ointment (6% Benzoic acid, 3% sal acid) Azole or allylamine topical antifungals No need for systemics
T/F
Piedra is a superficial infection of the hair shaft
True
What are the organisms for black and white piedra?
Black piedra - Piedraia hortae – found in soil
(name simialr to tinea nigra - also brown)
White piedra - Trichosporon beigelii spp.
‘try a white bagel’
(now known to be made up of at least 6 different species) - also enviromental pathogen but can be a commensal
T/F
Positive culture for Trichosporon beigelii is always pathological
False
can be commensal
T/F
T. Beigelii spp can cause systemic disease in immune suppressed
True
T/F
Adults in tropical climates are most affected by Piedra
False
kids in tropical climates
What are the clinical appearnce of piedra infections?
Black piedra;
Scalp, face, sometimes pubic
causes asymptomatic brown-black nodules on hair shafts – can envelope shaft if large enough
Nodules are firmly adherent and can get breaks in hair at site of nodules
White piedra;
Face, axillae, pubic, sometimes scalp
grows within and outside of shaft forming a sheath-like nodule
- Less nodular than black piedra
White colour or can be red/green/light brown
Loosely adherent to hair
What does Dematiaceous mean?
Means dark coloured; brown-black fungi eg. Horteae werneckii (tinea nigra) Piedraia hortae (black piedra) Chromoblastomycosis organisms Phaeohyphomycosis organisms
What is a ‘Crush preparation’?
cut hair shafts in KOH – the nodules (of piedra etc) are crushed as the hairs are mounted on the slides for microscopy
T/F
White piedra is caused by Dematiaceous fungi
False
What are DDs of piedra?
pediculosis capitis (nits on hair) hair casts pubic lice trichomycosis axillaris/pubis trichorrhexis nodosa scales of psoriasis/seb derm or pityriasis amiantacea
What is Rx of piedra?
Cut affected hairs
Antifungal shampoo – 2% ketoconazole
Oral terbinafine in resistant cases
T/F
Dermatophytes live on keratin
True
produce keratinases and like cool temps of skin surface
local skin immunity also usually prevents deeper infection
What are the genera of dermatophytes?
Microsporum
Trichophyton
Epidermophyton
T/F
Microsporum spp are mainly anthropophilic
False
mainly zoophilic
Out of 16 species, 3 are anthropophilic, 2 are geophilic
The only common anthropophilic microsporum is M. ferrugineum
T/F
Trichophyton spp are mainly anthropophilic
True
14 species - 6 are zoophilic
Only 2 common zoophilic species are T. mentagrophytes Var mentagrophytes and T. verrucosum
Which dermatophytes are geophilic?
M. gypseum and M. praecox
- live in soil
T/F
Epidermophyton floccosum is zoophilic
False
E. floccosum is anthropophilic
This is the only species on epidermophyton in the dermatophyte genera
T/F
Typically zoophilic organisms cause a lot of inflammation and can cause pustules or vesicles – present as acute infections
True
geophilic organsims cause moderate inflammation and anthropophilic organisms cause mild or non-inflammatory disease and tend to be chronic presentations
T/F
Sebum inhibits dermatophyte infection
True
T/F
All dermatophyte infections except tinea capitis occur mainly in adults
True
What are risk factors for dermatophyte infection?
Team sports, prisoners, hostels etc
Downs syndrome
Immunosupression/HIV - more severe and recurrent
T/F
Dermatophyte infection M=F
False
not true for all types
Tinea pedis, cruris and unguim more in men
T/F
It is always preferable to get a species diagnosis from culture when treating dermatophytes
False
simple skin infections usually respond to topicals
- KOH prep can confirm if diagnosis unclear
If plannning systemics shoud get culture
T/F
Nails with onychomycosis should be cleaned with an alcowipe prior to taking clippings for culture
True
get rid of secondary pathogens on surface
Clip to most proximal point you can without causing pain
Also scrape under nail with a blade to collect debris
T/F
Dermatophyte samples sne to lab are cultured on Sabouraud dextrose agar at 25-30 degrees and sometimes also at 37 degrees for 2-4 wks
True
Identity confirmed by appearance of colonies, microscopic examination of conidia & hyphal patterns and biochemical tests
T/F
cycloheximide-containing Sabouraud media is sufficient for growth of all samples sent for fungal culture
False
Fine to grow dermatophytes but can inhibit non-dermatophytes e.g. in onychomycosis so need to use both plain and cycloheximide-containing Sabouraud media
Whihc types of dermaotphyte infection often need biopsy to diagnose?
What special stains are used?
Tinea barbae or Majocchi’s granuloma
as fungi deep in follicles
PAS or Grocott silver stain to see fungal elements
What are the commonist dermatophytes to cause tinea corporis?
T. rubrum is most common cause
2nd commonest is T. mentag var mentag
But can be any dermatophyte species
When is T tonsurans a common cause of tinea corporis?
If a child in the household has tinea capitis
A pt with an inflammatory type of tinea corporis who does outdoor activities is most likely to have what type/species of dermatophyte?
Geophilic types
esp Microsporum gypseum
T/F
T verrucosum can be acquired from exposure to cattle
True
Which dermatophyte species is acquired from rodents?
T. mentag var mentag
T/F
T. concentricum causes concentric red rings of tinea corporis
False
T. rubrum causes concentric red rings of tinea corporis
T. concentricum causes tinea imbricata
T/F
hair follicles act as reservoirs for dermatophyte and hairy skin more resistant to treatment
True
T/F
Incubation time for tinea corporis is 6-8 weeks
False
1-3 weeks
What is tinea profunda?
Tinea corporis with a large amount of inflammation like a kerion
Lesions look thick, verrucous or ‘granulomatous/infiltrated’
mycotic Sycosis is a variant - very inflammatory tinea barbae with deep inflammation of follicles like a kerion on the cheek
What is Tinea imbricata? whre does it occur?
Tinea corporis due to T. concentricum causes eruption of annular concentric rings and patterns a bit like erythema gyratum repens
In South pacific islands, central and S. America and asia
What is Majocchi’s granuloma? who is at risk?
Deep suppurative folliculitis cause by dermatophyte
Presents as red plaque with follicular pustules or nodules
Usually T. rubrum
can be T. violaceum or E. floccosum
At risk are women who shave their legs and have tinea pedis or onychomycosis - Must check their feet!
T/F
T. mentag var mentag commonly causes Id reactions
True
T/F
Intertrigo means any infection localised to a body fold site
True
bacterial, fungal, viral etc
What are the commonest dermatophytes to cause tinea cruris?
T. rubrum
T. mentag var mentag
E. floccosum
Same 3 for tinea manuum and pedis
T/F
Pts with tinea cruris often have tinea pedis
True
Must look for it!
T/F
Tinea cruris is common in women
False
rare in women
Risk factors for tinea cruris?
Tinea pedis/unguium
sweaty
obese
team sports/locker room use
T/F
tine acruris can be uni or bilateral
True
Can extend to bottom, waist, thighs (esp T rubrum) or to trunk and legs (esp T ment); E floccosum rarely spreads beyond groin. Scrotum usually spared (thin skin, not much keratin)
T/F
Eczema marginatum is a variant of tinea cruris
True
E. floccosum
Well demarcated tinea with vesicles and/or pustules in border
T/F
satellite lesions and scrotal involvement point towards candidal intertrigo rather than tinea cruris
True
How is tinea cruris managed?
Loose weight Keep cool Loose clothing (less heat) Dry thoroughly Talcum powder Wash contaminated textiles Treat tinea elsewhere Clean environment, avoid locker rooms topicals usually sufficient, may need systemic if inflammatory or extensive or failed topical treatment
T/F
tinea of the dorsal hands is tinea manuum
False
tinea manuum is dermatophyte of the palm and/or interdigital spaces
tinea of dorsal hands and feet is considered tinea corporis
Which dermatophytes most often cause tinea manuum?
T. rubrum
T. mentag var mentag
E. floccosum
Same 3 for tinea manuum and pedis
T/F
Non-dermatophyte fungi may cause infection resembling T manuum
True
Scytalidium dimidiatum and S. hyalinum
T/F
Tinea manuum is often pustular
False
usually non-inflammatory with white hyperkeratosis esp of the skin markings
Can be exfoliative, vesicular or papular, unuusal to be pustular but consider in any unilateral hand eruption
T/F
Tinea unguim of fingernails often present if there is tinea manuum
True
must check nails and feet!
T/F
tinea pedis of moccasin type often present if there is tinea manuum
True
must check nails and feet!
T/F
Bilateral tinea manuum is the norm
False
most often unilateral
50% have 2 feet, 1 hand syndrome
must check nails and feet!
T/F
80% of pts with unilateral tinea manuum will have 1 hand 2 feet syndrome
Fase
50%
T/F
Tinea barbae is dermaotphyte infection of beard areas of face and neck in men
True
T/F
Tinea barbae is usually due to anthopophilic dermatophyte spp
False
zoophilic types common - however most common are the trychophyton zoophilic types
T. ment var. ment, T. verrucosum
rather than microsporums which are more commonly zoophilic
T/F
Tinea barbae is often very inflammatory
True as zopphilic
Pt may feel unwell and have LNs
Majocchis granuloma may develop or suppurative abscess with sinus tracts
rarely mycotic sycosis (kerion)
can result in scarring alopecia
Anthropophilic types e.g. T. rubrum are more superficial
What are DDs for Tinea barbae (including Majocchis granuloma or mycotic sycosis)?
Sycosis barbae Bacterial folliculitis or impetigo HSV/zoster Pyoderma faciale Blastomycosis-like pyoderma Dental sinus tract Cervicofacial actinomycosis
T/F
Tinea faciei is often a difficult diagnosis
True
classical scaly edge often absent
scrape anything red and scaly on face esp resistant/progressive ‘seb derm’
T/F
E. floccosum never causes tinea capitis
True
T/F
T. tonsurans is most common cause of tinea capitis in Aus
False
M canis most common in Aus (75%),
T tonsurans second (10%)
T/F
The asymptomatic carrier state for tinea capitis often occurs in children
False
rarely in children
but common in adults esp after exposure to T tonsurans
T/F
People who are asymptomatic carriers of dermatophyte on their scalp do not need to be treated
False
need to treat as can spread infection
topical may surface - need repeat culture after Rx
If not treated use orals
What are the microscopic patterns of tinea capitis infection?
endothrix
ectothrix
favus
T/F
Ectothrix infections may fluoresce
Favus should fluoresece
Endothrix never fluoesce
True
What are the features of endothrix infections?
what are the main organisms?
Non-fluorescent arthroconidia within hair shaft
Anthropophilic species
Nearly always Trychphyton
esp Tonsurans and Violaceum also Soudanense (esp in Africa)
remember ‘TVSets are IN houses’
Clinically can be; scale only/ black dots /alopecia
What are the features of ectothrix infections?
what are the main organisms?
Hyphae and arthroconidia grow outside hair shaft – cause destruction of cuticle
Mostly Microsporon
Mostly zoophilic (M. ferrugineum and audouinii are exceptions)
May fluoresce under Wood’s lamp
Clinically can be scaly and patchy alopecia up to kerion
T/F
black dot tinea capitis is often caused by endothrix infections
True
The hairs are weakened from fungi growing inside so easily breaks off
What are the features of Favus?
what are the main organisms?
Hyphae and air spaces within hair shaft (no conidia)
Most severe form of tinea capitis
Mostly caused by T schoenleinii – blue-white fluorescence on Wood’s lamp
Clinically thick yellow crusts called ‘scutula’ composed of hyphae and keratin skin debris which develop around follicular orifi
Can lead to scarring alopecia (without a kerion)
Not seen in Aus unless in o/s traveller
what are scutula?
thick yellow crusts seen in Favus composed of hyphae and keratin skin debris which develop around follicular orifi
What are common/important causes of tinea capitis in Aus
Cash Allows Very Many TV Sets
M. Canis (cats, dogs)
M. Audouinii (anthropothilic)
M. Verrucosum (from cattle, very slow growing, kerion)
T. Mentangrophytes (quite common, guinea pigs, kerion)
T. Tonsurans
T. Violaceum
(T. Soudanense rare in Aus unless refugee etc)
(T. Schoenleinii rare, favus - rare in Aus unless refugee)
*CAVM are ectothrix, TVS are endothrix
What are the species of dermatophyte which fluoresce?
FACDs T ferrugineum (yellow) M audouinii (green-yellow) M canis (green) M distortum (yellow) T schoenleinii (blue-white/pale-dull green) T triple M T
What are the clinical patterns of tinea capitis infection?
6 types;
Grey patch – patchy alopecia with fine grey scale – esp ectothrix microsporum infections
Black dots - + mild scale - esp endothrix as weakens hair esp Trichophyton esp T. tonsurans
Diffuse scale with minimal alopecia - (resembles dandruff) eg. T. tonsurans
Diffuse pustular variant – patchy alopecia and scattered pustules or folliculitis, can be tender regional lymphadenopathy
Kerion Celsi - severe inflammation in a chronic tinea case; painful boggy mass, solitary or multiple, regional adenopathy common – can cause scaring alopecia esp if antibiotics given which can worsen the condition. Esp zoophilic, large spore ectothrix e.g. T mentagrophytes, T verrucosum
Favus
T/F
scalp hairs should be clipped to send for fungal MCandS for tinea capitis
False
pluck hairs, dont cut
if fluoresces can send hairs that fluoresce
take brushings from scalp but need to be vigorous (toothbrush, cytobrush, damp gauze) and can only be used to inoculate culture so no microscopy. Best yield is from edges of lesions
T/F
pts being treated for tinea capitis may develop an itchy papular dermatophytid reaction esp around helix of ears
True
Treat with TCS
What are the types of tinea pedis?
Soles;
Non-inflammatory moccasin type
Inflammatory vesicular type
Interdigital webspaces;
Interdigital athletes foot type
Ulcerative type
T/F
The feet are the most common site of dermatophyte infection
True
Interdigital type is most common
T/F
Tinea pedis rare in Kids
True
but higher insidence if downs syndrome
T/F
Tinea pedis rare in cultures where shoes are not worn
True
What are the common dermatophytes which cause tinea pedis?
T rubrum, tonsurans and mentagrophytes var interdigitale
E. floccosum
What non-dermatophyte organisms cause tinea pedis – like infections?
Scytalidium dimidiatum and S. hyalineum (moccasin & interdigital)
Candida spp. (interdigital)
Fusarium spp. (interdigital)
Cause the interdigital type
What is the dermatophytosis complex?
Means secondary infection of a tinea; usually bacterial
Often inflammation, maceration, and odour
Often occurs with interdigital tinea pedis esp ulcerative type
T/F
Trichophyton mentag var interdigitale commonly causes moccasin tinea pedis
False
T interdigitale can cause all the other 3 types of tinea pedis including vesicular dermatophyte of the sole (only cause of this) but not simple moccasin type
T/F
T rubrum and E floccosum can cause all types of tinea pedis except the vesicular sole type
True
Only Trichophyton mentag var interdigitale causes vesicular dermatophyte of the sole
T. interdigitale can also cause ordinary and ulcerative interdigital types
T/F
vesicular dermatophyte of the sole often causes an Id reaction
True
T/F
vesicular dermatophyte of the sole usually needs oral Rx
False
Responds to topicals
T/F
Interdigital type tinea pedis often needs antibacterial as well as antifungal Rx
True As often secondary bacterial infection = ‘dermatophytosis complex’ Condys bactroban sometimes oral ABs \+ topical antifungal
T/F
Moccasin tinea pedis responds to topicals alone
True
but may need keratolytic as well as antifungal
eg. lactic acid, glycolic acid or urea cream
same for tinea manuum
What are the indications for systemic antifungals in tinea pedis?
Recalcitrant disease
diabetes
immunosuppression
T/F
Onychomycosis is always due to dermatophyte spp?
False
onychomycosis can be caused by non-dermatophyte fungi (mould) and by candida
Tinea unguim is dermatophyte onychomycosis
dermatophytes cause 90% of onychomycosis
T/F
>50% of nail dystrophy is due to onychomycosis
True
T/F
Onychomycosis accounts for >50% of all nail disease
False
15-40%
T/F
approx 15% of nail dystrophy in children is due to onychomycosis
True
Risk factors for onychomycosis?
Male
Older age
Occlusive footwear
Repeated nail trauma
Genetic predisposition (T rubum in particular may be seen in AD pattern)
Other nail disease e.g. psoriasis
Co-morbidities – hyperhidrosis, diabetes(3x increase), PVD, HIV(often all nails), other immunosuppression
T/F
The feet and nails should always be inspected when dermatophyte is found elsewhere on the body
True
even kids with tinea capitis - dont forget!
T/F
Up to 2/3 of cases of tinea unguim of toenails also have tinea pedis
False
up to 1/3
Which toenails are most commonly affected by tine unguim?
1st and 5th toenails most commonly affected
? Due to trauma from shoes
What are the common cause if tinea unguim?
Mostly anthopophilic
T rubrum>T mentag var interdigitale>E floccosum
rarely microsporum
T/F
Epidermophyton spp are geophilic
False
E floccosum is only member of the genus and it is anthropophilic
Both the geophilic dermatophytes are types of microsporum
T/F
tinea unguim affects finger nails more than toe nails
False
toe nails more
T/F
tinea unguim affects multiple nails more often than a single nail
True
T/F
tinea unguim is always asymptomatic
False
Can cause discomfort and pain on walking, activity and when trimming nails
What are the complications of tinea unguim?
Tinea elsewhere – other nails (often), pedis (often), crura, manuum etc Cellulitis Osteomyelitis gangrene e.g. diabetics, immunocompromised etc Pseudomonas pyoderma paronychia Dermatophytid reaction EAC Urticaria EN Asthma/resp tract sensitization Psychosocial effects, work discrimination, poor sex life Damaged socks and stockings
What are the clinical types of onychomycosis?
DSTEP Distal and/or lateral subungual (DLSO) Superficial white (SWO) – 3 types Total dystrophic onychomycosis (TDO) Endonyx oychomycosis Proximal subungual (PSO)
T/F
Oral antifungals may be started based on a clinical diagnosis of tinea unguim
False
If positive fungal KOH prep in rooms can start systemic while awaiting culture. Otherwise should wait until results confirm fungus before starting oral antifungals
T/F
samples of tinea infection from the skin are likely to culture the same organism that is infecting the nails in concurrent tinea unguim
True
T/F
Distal and/or lateral subungual onychomycosis (DLSO) is the most common pattern of tinea unguim
True
can be any dermatophyte
Can also be caused by Scopulariopsis brevicaulis
T/F
In Distal and/or lateral subungual onychomycosis (DLSO), the organism invades via hyponychium and progresses proximally
True
distal or lateral nailfold is point of infection
proximal progression is reason clippings often negative
T/F
In Distal and/or lateral subungual onychomycosis (DLSO), there is often nail bed (subungual) hyperkeratosis, thick yellow nail plate & onycholysis
True
May progress to total nail dystrophy = total dystrophic onychomycosis (TDO)
What are the 3 types of Superficial white onychomycosis (SWO)?
Discrete white patches
Diffuse white change
Transverse striate white bands
T/F
Superficial white onychomycosis (SWO) is due to direct invasion of the dorsal nail plate
True
T/F
Superficial white onychomycosis (SWO) is a more common type in children
True
T/F
Superficial white onychomycosis (SWO) is only caused by dermatophytes
False
Esp T mentagrophytes var. interdigitale
also can be T. rubrum, tonsurans
Also Fusarium spp., Aspegillus spp., Acremonium, S, hyalinum, + S. dimidiatum (causes black discolouration of nail)
T/F
Scytalidium dimidiatum can cause black version of Superficial white onychomycosis
True
T/F
Superficial white onychomycosis (SWO) is more likely to respond to topicals than other types of onychomycosis
True
except if Transverse striate white bands
T/F
Superficial white onychomycosis (SWO) with Diffuse white change is often resistant to topicals
False
Transverse striate white bands type is resistant to topicals
T/F
Onychomycosis usually invovles both the nail bed and nail plate
True
except for endonyx onychomycosis - no real nailbed involvement
T/F
In endonyx onychomycosis there is no real nailbed involvement so no onycholysis or subungual hyperkeratosis
True
Nail plate turns white
Can look like diffuse WSO or leukonychia
T/F
total dystrophic onychomycosis (TDO) is the endpoint of other types of oncyhomycosis
True
T/F
Promary total dystrophic onychomycosis (TDO) is more often Non-dermatophyte environmental fungi than dermatophytes
False
More often candida than dermatophyte
T/F
In Proximal subungual (PSO) the organism invades under the proximal nailfold
True
T/F
In Proximal subungual (PSO) always think of HIV/AIDS or other causes of immunosupression
True
T/F Proximal subungual (PSO) is often caused by T mentagrophytes var. interdigitale
False
usually with T rubrum or non-dermatophyte fungi
T/F
chronic paronychia or chronic mucocutaneous candidiasis predispose to candidal onychomycosis
True
Otherwise kids >3 and adults rarely get primary candidal nail disease
T/F
Candida are common cause of onychomycosis in children under 3
True
T/F
Non-dermatophyte fungi (mould) onychomycosis affects toenails more than finger nails
True
often only one nail, esp great toenail
What makes you suspect Non-dermatophyte fungi (mould) onychomycosis?
isolated nail resistant to Rx positive microscopy but neg culture no tinea elsewhere May be Hx of walking barefoot outdoors
T/F
Dermatophytes are superficial mycoses and never cause invasice disease
False
Rarely dermatophytes can proliferate and become disseminated
Esp if immunocompromised and if chronic untreated tinea infection
T rubrum most commonly
Can cause ulcerating/draining dermal nodular lesions
Can also be tender nodules on extremeties
Rx is by surgical excision and systemic Rx – terbinafine, itraconazole, griseo, amphotericin B
T/F
It is unecessary to retest hair/scalp samples after a course of treatment for tinea capitis
False
Must retest
mycological cure is the endpoint NOT clinical cure
How long do fungal infcetions need to be treated for if using oral Rx?
Depends on site and agent Guide for terbinafine use; 1 wk for skin (corporis/faceii/cruris) 2-4 wks for manuum/pedis 4 wks for Capitis 6 wks for fingernails 12-16 wks for toenails
What is the dose of terbinafine?
250mg daily in adults (1 tablet) Wt based dose in kids; Under 20kg – 62.5mg/day (Qtr tab) 20-40kg – 125mg/day (Half tab) 40kg+ – adult dose Can do pulsed therapy for tinea unguim; 500mg daily for 1 week per month for 3 mnths for fingernails and 4 mnths for toenails
What is the dose of Griseofulvin for tinea capitis?
Adults 500mg-1g daily for 8-12 wks
Kids;
20mg/kg/day (up to 500mg) for 6-8 or even 12+ weeks
BAD guideline says if Wt >50kg should use 1g per day in single/divided dose
Same dose for other indications but last line agent as poor efficacy
T/F
terbinafine is first line for tinea capitis unless M Canis cultured
True
Aus Ther guidelines 2015
T/F
Fluconazole is weekly dosing except in tinea capitis as it accumulates in tissues
True
and rarely used in tinea capitis
T/F
It is not necessary to use a topical agent in addtion to systemics for tinea capitis
False
use alternate day antifungal shampoo – Nizoral 2% or selenium sulphide 2.5% (selsun gold) - daily for first wk then alternate days
To reduce shedding of organisms
T/F
Household contacts should be treated in cases fo tinea capitis
True
Examine all household contacts and treat if infected – esp if T tonsurans as highly infectious
Treat with systemic if clinical infection
Send samples in all cases even if clinically clear
If +ve treat with topical and retest – oral Rx if still +ve
What cases of tinea unguim can be treated topically?
Topical monotherapy suitable for:
- Distal subungual onychomycosis if under 50% of nail and no matrix involvement
Or;
- White superficial onychomycosis
What are topical treatments for tinea unguim?
Amorolfine 5% (Loceryl) nail lacquer once a week up to 12 months – effective in up to 50% of distal cases. Can prevent recurrence. Can cause itch, burning, redness
Miconazole (Daktarin) tincture
Bifonazole (Canestan) kit available with urea to lyse the nail – 6 wk treatment
What general measures should be advised in cases of tinea unguim?
Breathable footwear and cotton socks
Avoid/discard/wash old thongs/sandals etc
Can put naphthalene mothballs in shoes and tie up in plastic bag for 3 days
Keep feet clean and dry
Use antifungal or absorbent powder
Keep nails trimmed short and free of undernail debris, don’t share clippers
Treat household members if infected/ clean damp areas/ avoid locker-rooms, swimming etc
How can tinea unguim treatment be monitored?
After a few months should see normal nail growing through from prox fold. Make a mark w/ scalpel for pt to watch. If dystrophy stays distal until all grown out then cured. Need to retreat if dystrophy progresses proximal to mark
What can be done for tinea unguim if topical and systemic Rx failed?
Chemical or surgical destruction/removal of the nail followed by topical treatment
some reports of success with lasers or PDT but not standard care
How is mould-onychomycosis treated?
can use terbinafine or itraconazole but may be better cure rate from surgical avulsion + topical Rx
T/F
terbinafine has a 70-80% cure rate for tinea unguim
True
terbinafine is first line in adults and kids
T/F
Itraconazole has a 50% cure rate for tinea unguim
False
Both Itra and Flu -conazole have 70% cure rates
Itraconazole second line after terbinafine (but most expensive)
T/F
Tinea manum and moccasin tinea pedis can be significantly hyperkeratotic and should be considered in DD for acquired palmar/plantar keratodermas
True
What are risk factors for candidal infections?
Antibiotic use Diabetes Xerostomia Local or systemic steroid use Occlusion Hyperhidrosis Immunosuppression inc HIV
What are particular risk factors for candidal angular cheilitis?
Overlap of skin at angles – if no teeth or elderly Dentures/braces etc Drooling Eczema B12 deficiency
What are the types of candidal oral infection?
Pseudomembranous form (thrush) – thick white exudate
Chronic atrophic form – patch of erythema
Chronic hyperplastic form – adherent white plaques
Glossitis – painful inflammation/atrophy of dorsal surface of tongue
Denture stomatitis
Angular cheilitis (perleche)
What is the cause of erosio interdigitalis blastomycetica ?
Candidal web space infection
T/F
erosio interdigitalis blastomycetica is particularly likely to affect the webspace between the 2nd and 3rd fingers in those doing wet work
False
between 3rd & 4th digits most likely
T/F
granuloma gluteale infantum is caused by candida
False
Complication of primary irritant napkin dermatitis
But candidal napkin infection can look quite red and juicy so is DD
What are the types of candidal onychomycosis?
4 types;
- Chronic paroncyhia with secondary nail dystrophy
- Wet work or thumb-sucking children - Distal nail infection - Uncommon, often on steroid Rx or have Raynaud’s
- Total dystrophic onychomycosis
- due to chronic mucocutaneous candidiasis
- gross thickening and hyperkeratosis - Secondary candidosis - in ps with tinea unguim or psoriatic nail disease etc
What are the KOH prep findings of candida spp?
budding yeast and pseudohyphae
T/F
Itraconzole is first line for candidal onychomycosis
True
azoles work best
4 wks for fingernails, 12 wks for toenails
T/F
It is important to address risk factors when treating candida infections
True Eg. check for diabetes r/o B12 def in perleche Treat hyperhidrosis, xerostomia, drooling, eczema etc
What is Chronic mucocutaneous candidiasis?
How is it treated?
Resistant chronic candidosis of infection of skin, nails and mucosae
usually associated with immunodeficiencies
Need high dose systemic therapy - fluconazole;
400-800mg OD for 4-6 months (eradication)
Then 200mg daily (suppression)
Must monitor LFTs closely
T/F
Candida spp live in gut
True
Increased numbers if had course of antibiotics
- can trigger napkin candidiasis in infants
Which immunodeficiencies are associated with recurrent/resistant candida or Chronic mucocutaneous candidiasis?
SCID HyperIgE syndrome esp STAT3 (Job) and PGM3 types (less in DOCK8) APECED Autoimmune polyendocrinopathy type 1 MST1 deficiency disease Also Mucocutaneous candidiasis can be an immunodeficiency syndrome in itself with AD or AR inheritnece and various mutations described e.g. STAT1 gain of function mut Dectin1 mut CARD9 def IL-17 RA def IL-17F def ACT1 def
What is the organism responsible for Sporotrichosis?
Sporothrix schenckii
dimorphic fungus (can exist as mold/hyphal/filamentous form or as yeast)
present in soil worldwide
How is Sporotrichosis acquired?
Classically acquired from cutaneous inoculation e.g. via a prick from a rose thorn also orchids
Can also be carried by cats in skin ulcers and transmitted to humans (esp in Rio de Janeiro)
Can be multiple inoculation sites simultaneously
several wks incubation time
T/F
After innoculation by Sporothrix schenckii disease presentation depends on host factors
True
If no existing immunity to S. schenckii infection spreads to local nodes
If existing immunity no spread – forms a fixed ulcer or plaque
If immunocompromised can develop extensive cutaneous disease +/- systemic disease
How does Sporothrix schenckii spread to local LNs?
sporotrichoid spread over several weeks
starts as painless papule at innocualtion site - ulcerated and becomes purulent
Involved lymphatics become fibrosed - need to diagnose and treat early
What is histo of Sporotrichosis?
Suppurative and granulomatous inflammation in dermis and subcutis
Asteroid bodies often seen + may have may have Splendore-Hoeppli phenomenon
Yeast forms are cigar-shaped - hard to until stained; PAS or GMS
Which fungal infections may have Splendore-Hoeppli phenomenon on histo?
sporotrichosis, pityrosporum folliculitis, zygomycosis, candidiasis, aspergillosis and blastomycosis
T/F
Sporothrix schenckii will grow in different forms at either 25 or 37 degrees
True
What is treatment of Sporotrichosis?
Itraconazole 100-200mg daily for 3-6 months
Amphotericin B if severe disseminated disease
KI (saturated solution of potassium iodide – SSKI) has been used
What is Chromoblastomycosis?
slow growing verrucous plaque on an extremity
caused by one of several types of dematiaceous (pigmented) fungi
Characterised by histological finding of Medlar bodies (copper pennies) - round pigmented bodies
Most common in tropical / sub-tropical climates
What organisms cause Chromoblastomycosis?
Fonsy Cuddles Philippa
Fonsacea spp
Cladophialophora (Cladosporium) carrionii
Phialophora verrucosa
found in soil and decaying plants and wood
T/F
Chromoblastomycosis frequently ulcerates
False
Does not ulcerate
T/F
Chromoblastomycosis may have central resolution resulting in a annular lesion
True Usually a varrucous or granulomatous-looking plaque Can be annnular can be subcutaneous mass No constitutional symptoms
What is histo of Chromoblastomycosis?
Suppurative and granulomatous inflammation in dermis
– neuts, histiocytes, plasma cells, multinucleated giant cells
Pseudoepitheliomatous hyperplasia + intraepidermal abscesses
pathognomonic Medlar bodies (copper pennies) are round pigmented bodies found in histiocytes/giant cells and in interstitium in clusters or chains
May also see hyphae but unusual
How is Chromoblastomycosis treated?
Difficult to treat – involve ID specialist
Can excise small lesions + oral antifungals
Itraconazole 200mg/day for at least 6 months – cure in 80-90%
Terbinafine 250mg/day for at least 7 months 2nd line
Heat and cryosurgery have been used
Antibiotics if secondary bacterial infection
What is Phaeohyphomycosis?
Infection caused by any one of a group of demitaceous fungi which produce brown-black hyphae (due to melanin in cell wall) seen in the tissue sections
found in plants and soil
Can be considered a ‘subcutaneous’ mycosis and an opportunistic infection
What fungi cause Phaeohyphomycosis?
ABC most common; Alternaria, Bipolaris or Curvularia Spp Also; Exophiala jeanselmei and E. dermatitidis. Exserohilum or Phialophora spp
T/F Organisms responsible for Phaeohyphomycosis can cause infections classiifed as o Superficial o Cutaneous o Subcutaneous o Systemic
True
T/F
men have higher risk of Phaeohyphomycosis if outdoor work/activities
True
men more often affected
T/F
implanted material e.g. splinter is ofetn seen in histo of Phaeohyphomycosis
True
T/F
Pigmented hyphae in the dermis/subcutis are characterisitic of subcutaneous Phaeohyphomycosis
True
But are seen in the SC in superficial forms - tinea nigra and black piedra
and in SC/upper epi/nail in cutaneous forms - Scytalidium dimidiatum or S. hyalineum causing infection of palms, soles (moccasin type) or interdigital spaces or onychomycosis mimicking dermatophytosis
What is treatment of subcuatneous Phaeohyphomycosis?
excise completely if possible
6-12 months itraconazole for extensive localised or systemic disease
T/F
cutaneous cryptococcosis causes lesions resembling keloid scars
False
Lobomycosis does this
seen in Central and S America
T/F
chains of thick-walled yeast-like cells – ‘brass knuckles’ are characteristic feature of histo of Lobomycosis
True
What causes cryptococcosis? How is it acquired?
encapsulated yeast Cryptococcus neoformans
found in bird droppings (pigeons)
Most common disease is primary lung infection which disseminates to CNS, bones and skin(15%)
Primary cutaneous cryptococcosis can occur by direct inoculation but is very unusual and systemic disease needs to be ruled out
T/F
extra-pulmonary Cryptococcus is AIDS-defining illness
True
disease is mainly seen in setting of AIDS
T/F
cutaneous cryptococcosis can be treated with itraconazole
True
Must r/o HIV and assess for systemic disease - CT chest, MRI brain, bone scan
What is Mycetoma?
AKA Madura foot
Granulomatous infection of dermis and subcutis which forms draining sinuses containing characteristic grains called sulphur granules or sclerotia
What are the types of Mycetoma?
Actinomycotic mycetoma – caused by actinomycetes; esp Central & S America
Eumycotic mycetoma – caused by true fungi; esp Africa
Botryomycotic mycetoma – caused by true bacteria (rare)
What organisms cause Eumycotic mycetoma?
Madurella spp., Pseudallescheria boydii, acremonium spp., Fusarium spp
What is the management of Eumycotic mycetoma?
Must excise en mass with large margin of normal tissue before bone becomes involved
Then use systemic antifungal Rx for long period
NB bacterial types can usually be treated with long term antibiotics only
What are the categories of systemic mycoses?
endemic mycoses (true pathogens) and opportunistic systemic mycoses
What are the dimorphic fungi?
What disease do they cause?
can exist as mold/hyphal/filamentous form or as yeast; Sporothrix schenckii (sporotrichosis) Histoplasma capsulatum var. capsulatum (histoplasmosis) Blastomyces dermatitidis (blastomycosis) Coccidioides immitis (Coccidiomycosis) Paracoccidioides brasiliensis (Paracoccidiomycosis)
All except Sporothrix schenckii (sporotrichosis) are endemic systemic mycoses. S schenckii is in the subcutaneous mycoses group
T/F
Dimorphic fungi can change between mould and yeast forms which help them evade the immune system
True
T/F
Endemic mycoses most often cause pulmonary disease through inhalation of conidia
True
Skin lesions can be primary through traumatic inoculation into the skin or secondary from dissemination of disease which has originated elsewhere in the body (usually pulmonary)
Where is Histoplasma capsulatum found?
In soil in warm climates. Africa + C & S America
Carried by birds and bats + in their feaces – caves, chicken coops, old buildings etc
T/F
Endemic mycoses can cause EN
True
esp Coccidiomycosis
T/F
There are 4 patterns of skin manifestation of disseminated Coccidiomycosis
True
- Papule, pustule, plaques, abscesses esp on face
- Ulcers
- Diffuse macular eruption (toxic erythema)
- Hypersens rcn- EM, EN
T/F
Endemic mycoses are mainly found in soil in Central and South America
True
Blastomyces dermatitidis most widespread; Eastern USA & Canada. Africa, India
Only Histoplasmosis is found in Australia
T/F
Histoplasma spp is found in Australia and infections (histoplasmosis) have been reported from most states
True
esp in caves where bats live
T/F
Tissue samples sent for culture for suspected Endemic mycoses should be cultured at 32 and 37 degrees
False
25+37˚C
Can do PCR on tissue for histoplasmosis
NB Sporothrix schenckii isolates grow best at 35 degrees
T/F
IV amphotericin B and/or iraconazole are the treatment for Endemic mycoses
True
T/F
Localised skin Sporotrichosis responds well to potassium iodide
True
4-6 ml three times a day for 2-4 months
T/F
Oral ulcers are seen in systemic histoplasmosis
True
What are skin findings of histoplasmosis
Non-specific cutaneous nodules or vegetative plaques
Pathology shows Intracellular yeast with rim of clearing (in histiocytes & giant cells)
T/F
A serology test is available for histoplasmosis
True
can alos do PCR on blood for disseminated disease
T/F
Amphotericin B active against all opportunistic fungal pathogens
True
Voriconazole also works well but not for zygomycosis
T/F
All dimorphic fungi can cause sporotrichoid spread
True
T/F
some opportunisitc fungi and those that cause phaeohyphomycosis can cause lesions with sporotrichoid spread
True
e.g Fusarium spp., Alternaria spp
T/F
examples of opportunisitic fungal pathogens include
Aspergillus spp
Zygomycosis (Rhizomucor spp., Rhizopus spp., Absidia spp.)
Hyalohyphomycosis; Fusarium (fusariosis), Penicillium, paecilomyces
Trichosporon spp.
Penicillium marneffei
Pneumocystis jirovecuii (PCP)
and candida spp
True
The endemic mycoses pathogens and those causing Phaeohyphomycosis are often also considered opportunisitic
