Transcript fungal infections of the skin (1)x

Fungal Infections of The
Skin
Skin fungal infections are clinically divided into:
Superficial
 Tinea versicolor, Piedra (Trichosporosis), and
Tinea nigra.
Cutaneous
 Dermatophytosis, Candidiasis of skin and
mucosa, nails and others.
Subcutaneous
 Mycetoma, Sporotrichosis,
Chromoblastomycosis, and others.
Superficial Mycoses
o Infections in which a pathogen is restricted to the
stratum corneum, with little or no tissue reaction.
o Affect the upper dead layers of skin or hair shaft.
o Painless and usually do not provoke immune
response.
o They include:

Tinea versicolor

Tinea nigra

Piedra
Tinea Versicolor
o Tinea versicolor is a chronic fungal infection of the
skin. More common in teens and young adults.
o The fungus interferes with the normal pigmentation of
the skin resulting in small, discolored patches (white,
pink, tan or dark brown, slow-growing, scaly and
mildly itchy)
o Common sites: the back, upper arms, chest, and neck.
o Sun exposure make tinea versicolor more apparent.
o Tinea versicolor often recurs, especially in warm,
humid weather.
o Causative agent: Malassezia furfur, and
Malassezia globosa. Lipophilic yeasts.
o Both are normal flora of skin cause disease when
overgrow. (not contagious)
o Triggering factors: Hot, humid weather, excessive
sweating, oily skin, hormonal changes and
weakened immune system.
o Diagnosis:
 Skin scraping: potassium hydroxide (KOH). which
dissolves keratin and make it easier to see the fungi.
 Culture: add oil to the media Sabouraud dextrose
agar (SDA).
Pityriasis versicolor
commonly causes
hypopigmentation in people
with dark skin.
Microscopy: Tinea versicolor
Positive for short hyphae and yeast cells:
Spaghetti and meatballs.
Tinea nigra
o Dark brown to black painless patches on the
palms of the hands and the soles of the feet.
o Causative fungi: Hortaea werneckii (acquired
from soil or wood)
o Diagnosis:
o Skin scrapings: in 10% or 20% KOH, brown
septate hyphae.
o Culture on Sabouraud dextrose agar (SDA) &
Mycobiotic agar, growth of dematiaceous
fungus (produce melanin in their cell walls).
Agar plate with the black yeast Hortaea werneckii
Skin scrapings in 10% KOH: dark
olivaceous (dematiaceous) hyphal
elements and 2-celled yeast cells of
Hortaea werneckii
Piedra (Spanish; stone or rock)
o Asymptomatic infection of the hair shaft, causing
nodules on the hair shaft (scalp hair, mustache, and
beard) leading to weakness and break of the hair.
o Black piedra:
Piedraia hortae. Dark nodules hard and firmly
attached to hair shaft.
o White piedra:
Trichosporon beigelii. Lightly pigmented, white to
brown nodules soft, loosely attached.
o Diagnosis:
Direct Microscopy: test the hair using 10% KOH.
Culture on Sabouraud's dextrose agar (SDA).
Hair with black Piedra
white piedra
Treatment of Superficial infections
o
2% salicylic acid or 3% sulfur ointments or
Whitfield's ointment.
o
Anti fungal: Ketoconazole topically or
systemically.
o
Piedra: clipping or shaving the hair or apply 2%
salicylic acid or 3% sulfur ointment or nizoral
shampoo (contains Ketoconazole)
Cutaneous fungal infection:
- Dermatophytosis.
- Candidiasis.
Dermatophytosis
• Fungal infections of the Keratinized tissues of
the body : scalp, glabrous skin, and nails
• caused group of fungi known as
dermatophytes which are primary
pathogens.
Transmission:
• Geophilic species: soil saprophytes.
• Zoophilic species: animals (goats, sheep, camel,
cows, horses) .
• Anthropophilic species: humans.
• From one body area to another.
Dermatophytes Etiology (filamentous mold like
fungi):
• Microsporum: infections on skin and hair.
• Epidermophyton: infections on skin and nails.
• Trichophyton: skin, hair, and nails.
• Clinically: Tinea or ringworm
T. capitis
T. corporis
T. pedis
T. cruris
scalp
skin
foot (Athlete’s foot)
groin
Diagnosis: KOH and culture on SDA. (skin scraping,
hair, or nail).
Microsporum canis
Trichophyton mentagrophytes
Epidermophyton floccosum
Tinea Capitis
 Ringworm of the scalp and hair shafts.
 Most common in toddlers and school-age children.
 Highly contagious infection: by direct contact or
by sharing objects like combs or from animals.
 Slow growing, scaly, gray or red round patches
(ring). The hair is fragile and break off at or just
above the scalp (black dots).
 Severe inflammation may cause scarring or
permanent hair loss.
 Diagnosis: Woods lamp, KOH & culture.
 Treatment: oral or topical (shampoo). Griseofulvin
Tinea capitis
Complications: Kerion result from host's response to the
fungal infection of the hair follicles of the scalp and beard
accompanied by secondary bacterial infection(s)
Tinea Corporis (body ringworm)
 Itchy, red circular or irregular rash with healthylooking skin in the middle (ring). It can be flat or
slightly raised. Mainly on the trunk or the face.
 Transmission: from human, animal, objects or soil.
 Predisposing factors: humid or crowded
conditions, excessive sweating, sports such as
wrestling or football, wearing tight clothing.
 Immunocompromised: widely disseminated and
may invade the dermis. Difficult treatment
 Diagnosis: ?????
 Treatment: Topical or oral (Griseofulvin, azoles or
terbinafine)
Ringworm in healthy & immunocompromised
Tinea unguium & Tinea pedis
Candidiasis (Yeast Infection)
• Candida is a yeast that is a normal flora.
Candida albicans is the most common spp.
• Candidiasis: Over growth of candida on skin
(particularly warm & moist areas), genitalia, throat,
mouth or blood.
• Oral candidiasis (thrush), diaper rash, yeast
infection of genital area (vulvovaginal candidiasis),
invasive candidiasis, candidemia.
• Symptoms and treatment depend on which part of
the body is infected.
Oral Candidiasis (Thrush):
• Candidal infection of the mouth or throat.
• White batches in the mouth and tongue with
redness, cracking at corners of the mouth, sore
throat and difficult swallowing.
• Most often seen in: Infants, elderly, antibiotics
treatment, immunocompromised (e.g. AIDS,
steroid treatment, diabetes, chemotherapy
patients……..).
• Treatment depends on: immune status, age and
severity of the infection.
Antifungals: mouthwash, dissolvable pills.
Angular cheilitis: mouth corners
•
Yeast Infection of the Genitals
Vaginal candidiasis: Common symptoms:
o Extreme itching in the genital area.
o Soreness and redness in the genital area.
o White, clumpy vaginal discharge.
o Painful intercourse.
•
•
Symptoms in men include (candidal balanitis):
red rash on genitalia and penis with itching or
burning.
Sexual partner should be treated as well.
•
Diaper Rash
o Some diaper rashes can be caused by candida.
o Symptoms: Dark red patches on the diaper area,
especially in the folds near the thighs or yellow,
fluid-filled spots that open and become flaky.
o Treatment: topical antifungal (cream, ointment,
or powder).
•
Invasive candidiasis & candidemia: risk factors:
weak immunity, hospitalization esp. in ICU, recent
surgery, central line (catheter), low birth weight.
o Vague symptoms, no response to antibiotics,
treat with IV antifungal.
Subcutaneous Fungal Infection:
- Mycetoma: endemic in different parts of KSA.
- Chromoblastomycosis.
Chromoblastomycosis
Madura Foot (Mycetoma)