fungal skin infections Flashcards
what are tinea ?
fungal nail or skin infectionsd
what are dermatophytes ?
fungi that require keratin for growth
in what form do the dermatophytes natrually exist in ?
molds with hyphae
what anti fungal drug is not effective against dermatophytes ?
nystatin
how is a dermatophyte infection diagnosed ?
usually clinical diagnosis
if not KOH prep test , the KOH dissolves epidermal keratinocytes
what is tinea unguium and what is the treatment ?
also called onchomycosis
terabinifine or itracanazole oral
what is tinea pedis and how does it occur ?
athletes foot
feet in sweaty warm environments
classically between toes
what is the treatment and if left untreated what can athletes foot lead to ?
scaling
treatment is topical anti fungals , ay 7aga azole
what is ringworm and what is the presentation ?
tinea corpis
itchy circular or oval red patch
red border with a central clearing
what is tinea capitis ?
dermatophyte infection of the scalp
occurs in children may be associated with hair loss in the affected area
how is tinea capitis treated ?
oral antifungals either by terbainifine or itraconazole
what is tinea cruris ?
jock itch
more common in men
occurs after physical activity
red patch on inner thigh
what is the cause of tinea versicolor and what is the other name for it?
also called pityrasis versicolor
caused by the species malassezia
how does malassezia cause tinea versicolor ?
malassezia is part of the normal skin flora but since it is dimorphic it can transform to the mycelial form and cause disease
what are the triggers for transformation of the malassezia species ?
hot humid weather
sweating
topical skin oils
what is the pathophysiology associated with tinea versicolor ?
there is degradation of lipids turning them into acids , this causes damage to the melanocytes and results in hypopigmented patches ( does not consume keratin )
what is the classic patient associated with tinea versicolor ?
patient that has just come back from a beach vacation that is tanned but with hypopigmentd patches
what does the KOH prep test show with tinea versicolor ?
shows hyphae and yeast cells
spaghetti and meatballs appearance
what is the treatment for tinea versicolor ?
topical azoles
selenium sulfide
what is the mechanism of action of selenium sulphide ?
promotes shedding of the stratum corneum
what is the causative agent of sporotrichosis ?
sporothrix schenckii
where is sporothrix schenkii usually found ?
exists as a dimorphic yeast that lives on plants
what is the other name for spoptrichosis ?
rose gardeners disease
what is the presentation of sporotrichosis and how does it happen ?
papules at the site of trauma days to weeks later
spores travel up the arm via lymphatics by ascending lymphaginitis
what is the treatment of sporotrichosis ?
itraconazole
saturated solution of potassium iodide SSKI
