Superficial Fungal Infections Flashcards
dermatophytosis is a
superficial mycotic infection of the skin
tinea is the latin word for
fungus
dermatophytes are
a group of filamentous fungi that require keratin for growth- survive on dead keratin
most superficial fungal infections are caused by which 3 genera of dermatophytes
(trichophyton, Epidermophyton, microspore)
how are superficial fungal infections generally transmitted
direct contact, fomites, environment (soil), animals
what are some predisposing host factors that may increase the chance of a superficial fungal infection
moisture (occlusive clothing/ shoes, warm humid climates), genetic susceptibility, impaired immunity (ex- diabetes, HIV, chemo)
tinea pedis is most commonly caused by ___________ and _________
dermatopytes
gram - bacteria that are ulcerative
which of the following is false about athletes foot
1. females are more likely to get it than males
2. prevalence increases with age
3. 70% will acquire it in their lifetime
4. marathon runners have a 30% prev rate
5. all of the above are true
1- males 4x more likely
what are the 4 variations of athlete’s foot
chronic interdigital infection
mocassin type infection
vesicular
ulcerative
what is the most common variant of athlete’s foot
chronic interdigital infection
describe the sx of chronic interdigital infxn
often between 4th and 5th toe
scaling, fissuring, whitened, thickened
burning, itching, malodorous
describe the sx of moccasin type infection
typically both feet
mild inflammation + diffuse scaling
toenails may be affected
describe the sx of vesicular type tinea pedis
Small vesicles near instep + mid anterior plantar surface
Typically with skin scaling
describe the sx of ulcerative type tinea pedis
Weeping and inflamed
Often malodorous due to secondary bacterial infxn
in tinea pedis fungus invades the __________, there is __________ initially or the patient may be ____________
outermost layer of the skin
drying and scaling initially
pt may be asymptomatic
what promotes fungal growth
moisture + increase temp by hot sweaty feet
list 2 differential dx for tinea pedis
Contact dermatitis, eczema, psoriasis, or bacterial infxns
list 2 nonpharm measures for tinea pedis
Mainly focused on prevention of recurrence + avoiding transmission
Avoid standing barefoot in public spaces, manage hyperhidrosis (antiperspirants or absorbent powders - talc/ aluminum Cl), allow shoes to dry thoroughly, avoid tight fitting shoes, breathable shoes- leather/ canvas allow feet to breathe
Personal hygiene: wash feet and dry thoroughly, change socks daily (avoid nylon materials), launder items used by infected person often + don’t share towels
what are the 4 classes of pharm tx for tinea pedis
allylamines
imidazoles
misc
hydroxypyridone
list the drug that is an allylamide that treats tinea pedis
terbinafine
what 3 topical imidazoles may be used to tx tinea pedis
miconazole, clotrimazole, ketoconazole
what 2 topical hydroxypyridones may be used to tx tinea pedis
ciclopirox
undecylenic acid
what is the 1 drug that is topical in misc for tx of tinea pedis
tolnaftate
how should terbinafine topical be used?
app 1-2x/d F4wks, 1-2wks if mild
rank the following topical TP tx from most to least pref: clotrimazole, tolnaftate, terbinafine, miconazole
terbinafine > clotrimazole/ miconazole > tolnaftate
what class of topical agents is pref in TP
allylamines
T or F: tea tree oil is effective for TP tx
F- but no harms
T or F: recurrence of TP is common
T- tx failure in 30% cases often d/t poor adherence- need to assess cause
product selection in TP should be based on
individual preference
what is a major downside of topical ointments for TP
remain on skin longer = can occlude + cause maceration = slowed skin healing
how should you apply topical TP products
Apply to clean dry area
Affected area including 2-3cm beyond border
Most products (Ex- creams, lotions, etc) = apply/ massage into area BID F4wks (should be used for ~1wk after infxn cleared to prevent recurrent infxn)
Sprays/ powders - apply to dry footwear and skin (check directions)
you should refer for TP if there is no improvement in _____________ or sx are not completely resolved by __________
no improvement after 2wks
not completely resolved after 6wks of tx
systemic tx for TP should be considered in pts with
immunocomp, DM, tx failure, mocassin type presentaion
prior to using systemic tx for TP, a _________________ should be done
microscopy/ culture growth (to confirm presence of dermatophyte)
what allylamide may be used for systemic tx of TP
terbinafine
what azoles may be used for systemic tx of TP
itraconazole
fluconazole
T or F: topical antifungal/ CS combinations may be more efficacious than single entity antifungal agents for TP
F- rec to aviod due to reduced eff + incr cost + SEs
jock itch involves the ___________ area and occasionally the _________
groin, medial and upper pts of thight, pubic area, occasionally anal cleft
(may also include buttocks)
T or F: tinea cruris often spares the penis and scrotum
T
3 principle dermatophytes for jock itch
T. rubrum (most common), T. mentagrophytes, E. floccosum
how is tinea cruris transmitted
Contagious- transmitted by contaminated towels, hotel bed sheets, or autoinoculation from reservoir on hands or feet (caution- pts with tinea pedis- can spread from infected feet to groin when putting on underwear)
list 2 RFs for tinea cruris
Moist conditions including tight fitting/ wet clothing/ undergarments
Humid climates
Genetic predisposition
Immunocompromised (DM, HIV, chemo)
Males- esp in summer months
tinea cruris is often _____________ due to inner thigh contact. it leaves __, __________ lesions with ___________ margin
bilateral/ symmetrical
round, well defined bordered lesions with raised erythematous margin
which of the following applies to tinea cruris
1. dry scaling is common
2. may be asymptomatic
3. can become macerated + infected
4. all of the above
4
list 2 differential dx for tinea cruris
Candidiasis (v red with poorly defined borders),
seborrheic dermatitis (usually also involves scalp, face, etc)
psoriasis (symmetrical erythematous plaques)
bacterial infections
list 2 nonpharm tx for tinea cruris
Avoid tight fitting clothes to reduce moisture at affected area
Wear clothes made out of breathable fibers (cotton)
Dry all areas completely (use separate towel to dry groin area)
Laundering of contaminated clothing separately
Drying powders- no evidence + concern that cornstarch could encourage fungal growth by acting as food source for yeast (may help reduce moisture + rubbing)
T or F: you should recommend a drying powder for tinea cruris to keep the area less moist
F- no evidence + concern that cornstarch could encourage fungal growth by acting as food source for yeast (may help reduce moisture + rubbing)
what are the 3 imidazole, 1 hydroxypyridone, and 1 allylamine topical tx for tinea cruris
clotrimazole, miconazole, ketoconazole
ciclopirox olamine
terbinafine
what are the 3 systemic tx for TCruris
oral terbinafine, fluconazole, itraconazole
what 2 drying powders are there for TC
Tolnaftate 1% cr/spray (Tinactin)- BID F2-4wks
Undecylenic acid (Fungicure) BID F2wks
tinea corporis infects the _____________, less commonly can affect the ______
hairless skin of trunk and arms (excludes face, hands, feet, groin)
less commonly face
what are teh 3 possible organisms for TCorporis
T. rubrum (most common), M. canis, T. mentagrophytes
describe TCorprois presntation
starts as flat, circular, scaly spots with central clear portion
raised vesicular red border - may have pustules within active border
occurs on upper body and extremities
usually asymptomatic, occasionally pruritic
how is TCorporis transmitted
Direct skin to skin contact (ex- wrestlers), animal contact, fomite, environment
RFs for TCorporis
Humid climates, impaired immune states, occlusive clothing, genetic predisposition
how is TCorporis tx
Similar to Tinea cruris
Usually used for longer tx period (~4wks)- exception = topical terbinafine F1wk
the prev of tinea unguium increases in
elderly, DM, immunocomp
what organisms may cause tinea unguium
T. rubrum (50-70%), T. mentagrophytes (5-17%), E. floccosum, many other dermatophytes
Rarely caused by candida or molds (ex- aspergillosis)
how is tinea Unguium transmitted
1/3 causes associ wtih TP
describe the presentation of tinea unguium
Usually toenails but can affect fingernails
Nail plate may separate from nail bed (onycholysis)
Subungual area thickens (subungual hyperkeratosis)
Nail plate turns yellowish/ brown or white
Needs physician to diagnose via nail clipping: culture, direct microscopy (KOH exam), biopsy
Hallmark sx: thickening, discoloration, separation
what are the 3 hallmark sx of tinea unguium
thickening, discoloration, separation
what are the 3 types of tinea unguium
Distal lateral subungual onychomycosis (DLSO) - most common type
Superficial white onychomycosis (SWO)- 10%
Proximal subungual onychomysosis (PSO)- least common - may be a sx of immunocomp = refer
list 2 times when you should refer the pt for tinea unguium
Pt has not been previously dx
>3 nails affected or involvement of >50% nail- PO tx rec
Suspected drug or disease induced
Pt immunosuppressed
Poorly controlled diabetes or pts with peripheral vascular disease
<18yrs
Nail presentation: trauma to nail, pitting, lifting
what is preferred in tx of tinea unguium? topical, oral, or surgical tx?
oral- 1st line esp for more extensive nail involvement
surgery = last resort + not always successful
topical = less eff than systemic tx due to poor penetration, recurrence after stopping, poor adherence
what are 5 pharm tx for tinea unguium
topical efinaconazole
topical propylene glycol, urea, lactic acid
oral terbinafine
itraconazole
fluconazole
efinaconazole MOA
blocks production of ergosterol (important pt of fungal membrane) = loss of fxn, death, reduction in infxn
efinaconazole is mostly used for __________ TU cases
mild-mod
what are the directions on using topical efinazonazole
Apply 1 application to the dry toenail, preferably at bedtime for up to 48 weeks. (Big toenail 2 applications (see next slide). Afterwards, ensure to use the brush to spread around the entire toenail (cuticle, folds of nail and sides/underside of toenail and on the end of toenail and surrounding skin). Allow to dry for 30 seconds
No need to remove the medication weekly due to lack of medication build up
No need to debride or remove diseased nail
Monitor for application site vesicles and dermatitis (redness, itching, burning, stinging in surrounding areas)
T or F: jublia is only for toenails
T- not indicated for fingernail onychomycosis
tropical propylene glycol, urea, lactic acid is used in _________ cases of TU and has ______ systemic absorption
mild
minimal
what are the directions for emtrix use
applied daily to infected nail + under free edge, cover nail with thin layer + allow to dry for few min
Used up to 24wks
which can be used on fingernails- jublia or emtrix
emtrix
AEs of emtrix include
transient irritation of skin next to affected nail, whitening of nail, nail may become loose and detach
what is the drug of choice in TU
oral terbinafine (lamasil)
why is oral terbinafine the drug of choice in TU
best efficacy, tol, lower risk of DDI comp other PO options
oral terbinafine remains in nails ____ mths after stopping
8mths
what labs must be monitored with use of oral terbinafine
baseline LFTs + wks 4-6
oral terbinafine inhibits _________
CYP2A6
itraconazole is detectable in nails within _______ of tx
1-2wks
intraconazole is a strong ______ inhibitor
CYp3A4
what are the 2 types of itraconazole dosing for TU
pulse dosing: 200mg BID F1wk/mth, repeat 2-3 cycles
continuous dosing: 200mg daily F6-8wks 9fingernails), 12wks (toenails)
what type of itraconazole dosing is most commonly prescribed
continuous
what labs must be ordered for itraconazole
liver enzymes qmth
what is a 3rd line tx for PO tx of TU + useful in peds or DDI
fluconazole
describe the efficacy of the following for tinea infections
- bitter orange
- garlic
- tea tree oil
- vick’s vaporub
Bitter orange- T. corporis, T. cruris, T. pedis- insuff reliable evidence
Garlic - T. pedis - possibly effective (garlic gel cont 0.6% ajoene) but insuff reliable evidence
Tea tree oil: possibly ineffective
Vick’s vaporub- T. unguium- no proven benefit
growth of diseased area of nail should stop in _______ for toenails, nails should appear normal in _____
12wks
12-18mths
when should u FU with tinea pts
12wks
