Transcript Dermatophytes

Fungal Infections of the Skin
Dermatophytes and Yeasts
Rich Callahan MSPA, PA-C
ICM I – Summer 2009
We’ll review the 3 most common fungal skin
infections seen clinically
• Tinea, or dermatophyte infection. “Ringworm.”
• Tinea Versicolor, a cutaneous yeast infection
with malassezia furfur. (They renamed tinea
versicolor to pityriasis versicolor a few years ago,
but in everyday practice most everyone still calls it
tinea versicolor)
• Cutaneous Candidiasis, a cutaneous yeast
infection with candida species.
Superficial Fungal Infections
Break down into 2 Categories:
1.) Yeasts
• Single cells with asexual
budding
• Candida Albicans –
causes cutaneous
candidiasis. Affects skin,
oropharynx, genitalia –
likes humidity
• Malassezia furfur –
causes tinea versicolor –
likes moisture and lipidrich environment
2.) Molds, or
“dermatophytes”
• The “tineas” or
“ringworm”
• Active growth phase
forms filaments, or hyphae
which infiltrate
keratinized skin
• Infect skin, hair and nails
• Caused by
epidermophyton,
trichophyton,
microsporum spp.
Cutaneous Candidiasis
• Basically a “yeast infection” affecting moist, warm
occluded skin anywhere on the body
• Like groin creases, genitals, axillae,
inframammary, perianal, interdigital spaces,
occasionally presents as folliculitis
Candida is same species causing classic “yeast
infection” affecting reproductive tract of female
patients
Predisposing Factors
• Immunosuppression
-AIDS
-Malignancy
-chemo
• Environment
-Occlusion, heat
-Moisture, maceration
• Diabetes
• Infants
• Medications
-antibiotics
-oral/systemic steroids
• Pregnancy
Cutaneous Candidiasis – Clinical
Presentations
•
•
•
•
Intertrigo
Angular Cheilitis
Balanitis
Vulvovaginitis
Candida Intertrigo – Clinical
Presentation
• Brightly erythematous, moist, macerated
skin
• Often has milky, whitish, adherent film and
characteristic yeasty odor
• Main areas of skin change often have
surrounding “satellite” lesions – small
papules and pustules with areas of normalappearing skin in between
Cutaneous Candidiasis Diagnosis
• KOH preparation yields classic
appearance of budding yeast
pseudohyphae and spores
• Can be confirmed by fungal culture
when necessary
Candida Intertrigo - Treatment
•
•
•
•
Must dry out chronically moist area
Showers, baths, soaks
Use powders sparingly
Helps to try and cool the affected
environment
• Topical anti-yeast medications
• Systemic: Diflucan; Sporanox
Angular Cheilitis
• As we age skin starts to sag over lateral oral
commissures creating environment of
moisture and occlusion.
• Presents as erythematous, cracked, crusted,
itchy/painful lesions at corners of mouth.
• Treatment consists of low-potency topical
steroids, topical anti-yeast medications
Candidal
Balanitis/Vulvovaginitis
• “Yeast” infection of the genitals
• Can follow sexual activity and many other
activities altering various microenvironments
around the body
• Usually represents overgrowth of pre-existent
flora
• Characterized by burning, itching, pain, discharge,
dysuria, dyspareunia
• Topical/systemic anti-yeast medications.
Dermatophytes
aka “Ringworm”
• Many species can infect skin, hair and nails (any
non-viable keratin)
• Trichophyton Rubrum by far the most common
• Can infect hair follicle unit and become
trichomycosis
• When confined to skin, is called epidermomycosis
• Nail infection = onychomycosis
The Tineas – Occur from Head to
Toe
•
•
•
•
•
•
•
T. Capitis – hair/head
T. Faciale – face
T. Barbae – beard
T. Manus – hands
T. Corporis – body
T. Cruris – groin
T. Pedis – foot
The Tineas – Clinical
Presentations
The Tineas - Diagnosis
• KOH preparation
• Fungal Culture
• KOH Prep most often used in clinical practice:
Skin scrapings from affected area placed on glass
slide w/KOH solution + heated. In 5-10 minutes
keratin in specimen broken down to reveal fungal
hyphae and spores.
• Dermatopathology: Skin biopsy with PAS stain
can yield fungal forms on histologic analysis
The Tineas - Treatment
• Topical Antifungals – the azoles
(econazole, sertraconazole, clotrimazole,
etc.
• Terbinafine
• Ciclopirox
• Naftifine
• Systemics: Terbinafine, Itraconazole,
fluconazole, griseofulvin
Tinea Versicolor, aka Pityriasis
Versicolor
• Name of causative organism has changed –
formerly known as pityrosporum ovale,
now called malassezia furfur
• Lipophilic yeast – colonized skin, hair and
follicles roughly around puberty
• Has been implicated in terms of having a
role in the development of seborrheic
dermatitis – as of yet to be clearly defined
Tinea Versicolor
• Epidermomycosis with m.furfur yeast on children
and younger adults
• Prefers areas of high sebum production on trunk:
chest/back/axillae
• Presents as scaling pink macules and patches on
fair skin and scaling, hypopigmented patches on
tan skin.
• Often mildly pruritic or asymptomatic
• Normal resident of skin flora – more opportunistic
than contagious
T. Versicolor - Diagnosis
• Often a clinical diagnosis based on classic
history/appearance
• KOH prep yields classic “spaghetti and
meatballs” appearance of budding yeast forms
and spores
• Dermatopathology: Skin biopsy with PAS stain
often shows budding yeast forms
• Patients with chronic TV over many years often
spotted with hypopigmented macules
T. Versicolor – Treatment
• Topicals: Selenium sulfide/ketoconazole shampoo,
topical azole antifungals/terbinafine.
• Systemics: Ketoconazole pulse dosing,
itraconazole, fluconazole
• Often chronic course requiring periodic
maintenance/suppressive therapy
• Chronic, severe TV recalcitrant to treatment can
be presenting sign of HIV