| Fungi
and Human Disease |
 |
 Under
good sanitary conditions, Humans generally
have a reasonable level of innate immunity
to fungi and most of the infections
they cause may be mild and self-limiting.- However, fungi do pass the resistance
barriers of the human body and establish
infections.
- Fungal infections can be very resistant
and may require prolonged & persistent
treatment.
Natural Resistance
Depends on
- Fatty acid content of the skin.
- pH of the skin.
- Mucosal surfaces and body fluids.
- Epithelial cell turnover.
- Normal flora.
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| Introduction
to Fungi |
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Fungi grow in irregular masses and can
be broadly divided into two basic forms:
- Moulds:
Moulds are made up of long, multinucleated
filaments, or hyphae, that grow continuously
at the apical tip.
- Yeasts:
Yeasts spend the main phase of their
life cycle as a unicellular organism,
and they usually reproduce by budding.
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| Fungal
Skin Disorders |
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- Fungal skin disorders are common and
involve people of all ages.
- Fungi are ubiquitous organisms capable
of colonizing almost any environment,
including virtually all humans.
- When fungi do pass the resistance
barriers of the human body and establish
infections, the infections are classified
according to the tissue levels initially
colonized.
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| Fungal
Infections |
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Fungal infections
are classified according to the tissue levels
initially colonized:
- Superficial mycoses-
infections limited to the outermost
layers of the skin and hair.
- Cutaneous mycoses- infections
that extend deeper into the epidermis,
as well as invasive hair and nail
diseases.
- Subcutaneous mycoses-
infections involve the dermis,
subcutaneous tissues, muscle,
and fascia. These infections are
chronic and are initiated by trauma
to the skin. These infections
are difficult to treat and may
require surgical intervention.
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| Superficial
Mycoses |
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- Warm, moist conditions
can promote growth of numerous organisms
or allow fungal infection to develop
over another disorder of the skin or
nails especially in warm, moist areas
of body.
- Superficial fungal
infections are usually caused by yeasts
(e.g, Candida, Malassezia) or dermatophytes
(e.g, Trichophyton, Microsporum, Epidermophyton).
- Dermatophytes can
be acquired from people (anthropophilic),
animals (zoophilic), or soil (geophilic)
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| Superficial
Mycoses Types: |
- Candidiasis (Monilia)
- Dermatophytosis (Tinea)
- Pityriasis versicolor
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| I)
Candidiasis |
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Most Common Candida Species are:
- Candida albicans
- Candida tropicalis
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| Candida albicans, Spore Production |
Candida albicans, Yeast Colony |
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| Candidiasis
Body Regions |
- Skin
- Mucous membranes:
- Urinary tract
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| Candidiasis
Clinical Manifestations |
| Cutaneous and Subcutaneous |
Severe diaper rash |
- Oral
- Vaginal
- Onychomycosis
- Dermatitis
- Diaper rash
- Balanitis
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| II)
Dermatophytosis |
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- Dermatophytes are infection of the
skin, hair or nails caused by a group
of keratinophilic fungi.
- Dermatophytosis-causing species belong
to 3 genera of fungi:
- Microsporum
- Epidermophyton
- Trichophyton
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| Typical Mould |
Microsporumgypseum |
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| Trichophyton spp. |
Epidermophyton Floccosum |
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| Dermatophytosis
(Tinea) |
- Dermatophyte infections are commonly
referred to as ringworm, or tinea.
- Dermatophytes infect and survive on
dead keratin and persist in the stratum
corneum epidermidis. Rarely do they
penetrate below the surface of the epidermis.
- The skin responds to this superficial
infection by increased proliferation,
which leads to scaling and epidermal
thickening.
- The most common dermatophyte in the
world, Trichophyton rubrum, causes the
majority of skin infections that do
not involve the scalp.
About 10% to 20% of the world's population
is infected by a dermatophyte.
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| Tinea Infection
Locations: |
- Microsporum:
- Epidermophyton:
- Trichophyton:
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Hair, skin
Skin, nail
Hair, skin, nail |
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| Tinea Classification: |
| Tinea is further
classified according to its location on
the body |
- Tinea Corporis (Body) : Including
- Tinea Faciei (Face)
- Tinea Manuum (Hands)
- Tinea Pedis (Foot) "athlete's
foot"
- Tinea Cruris (Groin) "jock
itch"
- Pityriasis (Tinea) Versicolor
- Tinea Capitis (Scalp)
- Tinea Unguium (Nails) (Onychomycosis).
- Tinea Barbae "barber's itch"
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| Tinea Epidemiology |
- Contact and trauma
- Moisture & warmth
- Crowded living conditions
- Cellular immunodeficiency -> (chronic
infection)
- Re-infection is possible (larger inoculum
is needed, course is shorter).
- Antimicrobial use disturbing normal
flora
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| Tinea Transmission |
- Close human contact
- Sharing clothes, combs, brushes, towels,
bed sheets... (Indirect)
- Animal-to-human contact.
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| Tinea Clinical
Manifestations |
- Skin: Circular, dry, erythematous,
scaly, itchy lesions
- Hair: Typical lesions, "kerion",
scarring, "alopecia"
- Nail: Thickened, deformed,
friable, discolored nails, subungual
debris accumulation
- Favus on hair follicles
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| Tinea Corporis
Manifestations |
- The key characteristic of Tinea Corporis
is that the fungus involves the glabrous
(relatively hairless) skin.
- The infection is limited to the stratum
corneum of the epidermis.
- Vellus hair (the fine hair present
on glabrous skin) may be invaded, and
the hair follicle may serve as a reservoir
for the fungus.
- Infection is usually limited to the
stratum corneum of the epidermis (as
shown in the image).
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Tinea Manuum (Hands) |
Tinea Cruris (Groin) |
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Tinea Pedis (Athelete's foot)
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Tinea Unguium (Nails) |
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Tinea Capitis (Scalp) |
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| III)
Tinea Versicolor |
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- Superficial chronic infection of Stratum
corneum
- Etiology : Malassezia FURFUR (Pityrosporum
orbiculare) (Lipophilic yeast)
Malassezia Furfur yeast in skin |
Stained skin scale showing M. furfur
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| Clinical
Findings |
| Hyper-pigmented
or de-pigmented maculae (patches) on: |
- Neck.
- Chest.
- Back.
- Arms.
- Abdomen.
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| Treatment
of Fungal Infections |
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| Treatment of
Cutaneous Fungal Infections May Consist
of: |
- Topical Agents.
- Systemic Agents.
- Used Singly or in Combination.
- Usually, treatment is not started
until the diagnosis has been confirmed.
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| Topical
Agents |
- Topical treatment alone may be sufficient
for noninflammatory tinea corporis,
tinea cruris, tinea faciei, tinea manuum,
and tinea pedis.
- Topical agents can be divided into
three major categories:
- Imidazoles,
- Imidazole derivatives act
by binding to the cytochrome
P-450 system and blocking synthesis
of ergosterol, a vital component
of cell membranes.
- At higher concentrations,
imidazoles can have bactericidal
as well as fungicidal action.
- Major imidazoles iclude :
Miconazole, Econazole 1%, Ketokenazole
2%, Clotrimazole
- Allylamines
- Polyenes.
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| What
we offer: |
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 Miconaz
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