Dermatophyte fungal infections Flashcards
(25 cards)
Hair invasion types
Endothrix meaning fungal hyphae inside the hair shaft vs. exothrix meaning fungal hyphae inside the hair shaft and on the hair itself
Classification of dermatophyte infections
All ringworm fungi: Microsporum, Trichophyton, and Epidermophyton
Wet mount prep
For skin sample: heat up and then can look at it
For nail: can be left with KOH for 24hrs prior to examining
For hair: no need to prep it, just look under scope
Mosaic artifact
lipid droplets in a line between cells that can look like hyphae, will disappear with more heat and presssure
What type of hyphase in dermatophyte infection
branching hyphae
Wood’s light examination
On hair:
- microsporum infection and trichophyton floresce blue-green to pale green
On skin:
- tinea versicolor turns white-yello
- Bacterium infection Corneybacterium minuteissiumum causing erythrasma turns bright coral
Two-feet one hand syndrome
Usually caused by trichophyton rubrum
Treatment of tinea pedis
- Lamisil (terbinafine) is very effective
- 2/2 ID reactions may need topical steroids
- if entire plantar surface affected, more difficult to tx
Pitted keratolysis
Disease mimicking tinea pedis but Bacterial in etiology
on weight bearing part of soles of feet (slimy skin)
Pitted keratolysis clinical presentation
circular pits &/ furrows
Pitted keratolysis tx
Keep feet dry and antibacterial washing of feet
Tinea cruris vs. candida of the groin
Tinea cruris typically presents as unilateral hald moon shaped plaque that does not extend onto scrotum.
DDx of tinea cruris
Candida, intertrigo, erythrasma (scaly throughout not just at advancing border and a more red/brown)
Erythrasma tx
Topical azole (but not ketoconazole) or PO erythromycin/clarithromycin
Special fungal infections
Tinea verrucosum (very red and inflammed, caught from barn animals) Tinea rubrum (granulomatous rxn)
Is tinea capitis contagious
Yes, it can be spread by direct contact/through contaminated clothes unlike other fungal infections
Kerion
severe inflammatory version of tinea capitis with a boggy, tumor like mass
Lab medium for tinea capitis dx
Mycosels medium
Clinical patterns of tinea capitis
Diffuse scale (DDx: seb/atopic derm, psoriasis) Gray patch (DDx: seb/atopic derm, psoriasis) Black dot (DDX: alopecia areata, trichotillomania) Diffuse pustular (bacterial/dissecting folliculitis) Kerion (DDx: abscess/neoplasia)
Tineal capitis tx
Need oral antifungals (griseo is drug of choice in kids for 8-10 weeks)
MCC of scalp ringworm
Trichophyton tonsurans (does not flouresce)
Tinea amiantacea
Form of seb derm in kids with localized 2-8cm patches of large, brown polygonal shaped scale that adheres to the head and hair as it grows out
Tinea barbae tx
oral antifungals
Tinea barbae differentiation from bacterial folliculitis
Tinea usually starts in small area and grows, folliculitis outbreaks widely after shaving. And hair removal is easy and painless in tinea infection but difficult in folliculitis
