CUTANEOUS MYCOSES.pdf

cutaneous mycoses details
types of cutaneous mycoses

1. CUTANEOUS
MYCOSES
SUBMITTED TO
DR. POONAM
DR. SHIKHA
DEPARTMENT OF
MICROBIOLOGY
SUBMITTED BY
ANCHAL THAKUR
MMB-22-2502
MSC. MICROBIOLOGY
SEMESTER 2ND

2. INDEX
CUTANEOUS MYCOSES CLINICAL MANIFESTATIONS
LABORARTORY DIAGNOSIS
TREATMENT
PREVENTIONS
CAUSITIVE ORGANISM
CAUSITIVE AGENTS
CAUSITIVE ORGANISM
PATHOGENESIS

3. A fungal disease also called dermatophytosis that infect
only the keratinized tissue( skin, hair and nails)
They stimulate cell mediated immune response that
damage deeper tissues.
No living tissue is invaded, however a variety of
pathological changes occur in the host because of the
presence of the infectious agent and its metabolic products.


CUTANEOUS MYCOSIS

4. CAUSITIVE ORGANISMS
1.
2.
3.
Microsporum species
- infect skin and hair

Trichophyton species
- infect skin, hair and nail

Epidermophyton floccosum
-infect skin and hair

5. DERMATOPHYTOSIS
Dermatophytosis (tinea or ringworm) of the scalp, glabrous skin, and nails is caused by a
closely related group of fungi known as dermatophytes which have the ability to utilise
keratin as a nutrient source, i.e. they have a unique enzymatic capacity [keratinase].
The disease process in dermatophytosis is unique for two reasons:
Firstly, no living tissue is invaded the keratinised stratum corneum is simply colonised.
However, the presence of the fungus and its metabolic products usually induces an
allergic and inflammatory eczematous response in the host.
The type and severity of the host response is often related to the species and strain of
dermatophyte causing the infection. Secondly, the dermatophytes are the only fungi that
have evolved a dependency on human or animal infection for the survival and
dissemination of their species.

6. PATHOGENESIS
ADHERENCE
Arthroconidium (asexual spores produced by dermatophytes) adheres to the surface of the
tissue.
At the skin surface, long and sparse (thin) fibrils connect fungal arthroconidia to keratinocytes.
The arthroconidium then germinates into hypha, and hypha enters into the stratum corneum.
PENETRATION
After the adherence, dermatophytes need to obtain the nutrients for their survival. To use the
nutrients, the proteins, starch, cellulose, and lipids are degraded into smaller compounds.
Dermatophytes then secrete various enzymes like proteases, lipases, elastases, collagenases,
phosphatases, and esterases to degrade the complex compounds into simple ones.
Keratinases degrade the keratin present in the host tissues into oligopeptides or amino acids.
Proteolytic enzymes degrade the proteins of the skin. It helps in the penetration of the stratum
corneum.

7. DEVELOPMENT OF HOST RESPONSE
Dermatophytes have mannan, which suppresses the inflammatory response.
It also inhibits the proliferation of the keratinocytes, which allows for establishing the
persistent infection.

8. Clinical manifestations:
The common anthropophilic species are primarily parasitic on man.
They are unable to colonise other animals and they have no other
environmental sources. On the other hand, geophilic species normally
inhabit the soil where they are believed to decompose keratinaceous
debris.
Some species may cause infections in animals and man following
contact with soil. Zoophilic species are primarily parasitic on animals
and infections may be transmitted to humans following contact with the
animal host.
Zoophilic infections usually elicit a strong host response and on the skin
where contact with the infective animal has occurred ie arms, legs, body
or face.

9. TINEA PEDIS (ATHLETE'S FOOT)
Infections by anthropophilic dermatophytes are usually caused by
the shedding of skin scales containing viable infectious hyphal
elements [arthroconidia] of the fungus.
Desquamated skin scales may remain infectious in the
environment for months or years. Therefore transmission may
take place by indirect contact long after the infective debris has
been shed.
Toe web spaces are the major reservoir on the human body for
these fungi and therefore it is not practical to treat infections at
other sites without concomitant treatment of the toe web spaces.
Individuals with chronic or subclinical toe web infections are
carriers and represent a public health risk to the general
population, in that they are constantly shedding infectious skin
scales.

Trichophyton rubrum,
Trichophyton interdigitale and
Epidermophyton floccosum

10. TINEA CRURIS ( JOCK ITCH )
Tinea cruris refers to dermatophytosis of the proximal
medial thighs, preum and buttocks. It occurs more
commonly in males and is usually due to spread of the
fungus from the feet.
All ages can develop tinea cruris, adolescents and adults
more commonly than children and the elderly. Tinea cruris
can affect all races, being particularly common in hot
humid tropical climates.
Spread of the infection to the groin is commonly from the
feet (Tinea pedis) or nails (Tinea unguium) by scratching or
use of contaminated towels or bed sheets.
Trichophyton rubrum,
Trichophyton interdigitale and
Epidermophyton floccosum

11. TINEA UNGUIUM ( ONYCHOMYCOSIS )
Dermatophyte onychomycosis may be classified into two
main types;
(1) Superficial white onychomycosis in which invasion is
restricted to patches or pits on the surface of the nail.
(2) Invasive, subungual dermatophytosis in which the lateral,
distal or proximal edges of the nail are first involved,
followed by establishment of the infection beneath the nail
plate.
Distal subungual onychomycosis is the most common form
of dermatophyte onychomycosis.
The fungus invades the distal nail bed causing
hyperkeratosis of the nail bed with eventual onycholysis,
and thickening of the nail plate.
Trichophyton rubrum,
Trichophyton
interdigitale

12. TINEA CORPORIS ( RINGWORM )
Tinea corporis is a superficial fungal infection of the skin
that can affect any part of the body, excluding the hands
and feet, scalp, face and beard, groin, and nails. It is
commonly called ‘ringworm’ as it presents with
characteristic ring-shaped lesions.
Tinea corporis is found in most parts of the world, but
particularly in hot humid climates. It is most commonly
seen in children and young adults, however all age groups
can be infected including newborns.
Tinea corporis is spread by the shedding of fungal spores
from infected skin. Transmission is facilitated by a warm,
moist environment and the sharing of fomites including
bedding, towels, and clothing.
Trichophyton rubrum,
Microsporum gypseum
Microsporum canis

13. TINEA CAPITIS ( RINGWORM OF SCALP )
Tinea capitis refers to dermatophytosis of the scalp.
Three types of in vivo hair invasion are recognised:
ECTOTHRIX INVASION :-
Characterised by the development of arthroconidia
on the outside of the hair shaft. The cuticle of the
hair is destroyed and infected hairs usually fluoresce
a bright greenish yellow colour under Wood's
ultraviolet light.
Common agents include Microsporum canis, Nannizzia
gypsea, Trichophyton equinum and Trichophyton
verrucosum .
1.
Trichophyton equinum,
Trichophyton tonsurans
Microsporum canis
Trichophyton schoenleineii

14. Characterised by the development of
arthroconidia within the hair shaft
only. The cuticle of the hair remains
intact and infected hairs do not
fluoresce under Wood's ultraviolet
light.
All endothrix producing agents are
anthropophilic eg Trichophyton
tonsurans and Trichophyton violaceum.
Produces favus-like crusts or scutula
and corresponding hair loss.
Favus usually caused by Trichophyton
schoenleinii.
2.ENDOTHRIX HAIR INVASION:-
3.FAVUS:-

15. CLINICAL MATERIAL:-
LABORATORY DIAGNOSIS
Skin Scrapings, nail scrapings and epilated hairs.
In patients with suspected dermatophytosis of
skin [tinea or ringworm] any ointments or other
local applications present should first be
removed with an alcowipe. Using a blunt scalpel,
tweezers, or a bone curette, firmly scrape the
lesion, particularly at the advancing border.
In patients with suspected dermatophytosis of
nails [onychomycosis] the nail should be pared
and scraped using a blunt scalpel until the
crumbling white degenerating portion is
reached. Any white keratin debris beneath the
free edge of the nail should also be collected.

16. DIRECT MICROSCOPY:-
LABORATORY DIAGNOSIS
Skin Scrapings, nail
scrapings and epilated
hairs should be
examined using 10%
KOH and Parker ink or
calcofluor white mounts
ECTOTHRIX TINEA
CAPITIS
ENDOTHRIX TINEA
CAPITIS

17. CULTURE:-
LABORATORY DIAGNOSIS
Specimens should be inoculated
onto primary isolation media,
like Sabouraud's dextrose agar
containing cycloheximide
(actidione) and incubated at 26-
28C for 4 weeks. The growth of
any dermatophyte is
significant.
Specimen can also be
inoculated onto Potato
Dextrose Agar.
Culture of Trichophyton rubrum

18. IDENTIFICATION
Characteristic clinical, microscopic and culture features:-
TRICHOPHYTON
Trichophyton is a fungus that causes tinea, including
athlete’s foot, ringworm, jock itch, and similar
infections of the nail, beard, skin, and scalp.
It also develops smooth-walled macro- and
microconidia.
Macroconidia occurs directly on the hyphae or on
short pedicels.
They contain thin to thick cell walls that are clavate
to fusiform and 4 to 8 by 8 to 50 μm in size.
Macroconidia are absent or few in most species of
Trichophyton.
Microconidia are spherical, pyriform to clavate, or
irregular in shape. In addition, they are 2 to 4 μm in
size.

19. DERMATOPHYTES
COLONY
MORPHOLOGY
Microscopic
observation
Trichophyton rubrum
Velvety, red pigment on
reverse
Tear-drop, microconidia, a few long,
pencil-shaped macroconidia
Trichophyton
mentagrophytes
White to tan, cottony or
powdery, pigment variable
Clusters of microconidia cigar-shaped
macroconidia with terminal rat-tail
filaments
Trichophyton
tonsurans
Powdery to cream or yellow
with central furrows
Abundant microconidia, thick-walled,
irregular macroconidia
Trichophyton
schoenleinii
Smooth, waxy, brownish
Hyphal swellings, chlamydopsores,
favic chandelier
Trichophyton
violaceum
Very slow growing, waxy,
violet to purple pigment
Distorted hyphae, conidia rare

20. MICROSPORUM
'
Microsporum is a fungus that causes fungal
infections in the skin called tinea capitis, tinea
corporis, ringworm, etc.
Microsporum contains both macroconidia and
microconidia.
Macroconidia are large asexual reproductive
structures, while microconidia are small asexual
reproductive structures.
They occur on short conidiophores.
Macroconidia are hyaline and multi-septate. They
are also spindle shape or obovate. The size of the
macroconidia is 7–20 by 30–160 um. The cell walls of
the macroconidia are thin or thick and echinulate to
verrucose.
In comparison, microconidia are hyaline, single-
celled, smooth-walled, and 2.5–3.5 by 4–7 um in size.

21. DERMATOPHYTES COLONY MORPHOLOGY
Microscopic
observation
Microsporum audouinii Velvety, brownish, slow growing
Thick-walled chlamydospores,
conidia rare and irregular
Microsporum canis
Cottony, orange pigment on
reverse
Abundant, thick-walled spindle-
shaped macroconidia with up to
15 septa
Microsporum gypseum
Powdery, buff-colored Yellowish-
green
Abundant, thin-walled
macroconidia with 4-6 septa

22. EPIDERMOPHYTON


Epidermophton is genus of fungi that cause
fungal infections. It also causes superficial
and cutaneous mycoses, including E.
floccosum, and causes tinea unguium (fungal
infection of the nail bed), tinea corporis
(ringworm), tinea cruris (jock itch), and tinea
pedis (athlete’s foot).
Epidermophyton contains smooth, thin-
walled, club-shaped macroconidia and does
not contain microconidia.
Epidermophyton is an anthropophilic
dermatophyte that prefers infecting humans.
In comparison, zoophilic dermatophytes
prefer infecting animals rather than humans.

23. DERMATOPHYTES COLONY MORPHOLOGY
Microscopic
observation
Epidermatphyto floccosum
Slow growing, powdery, greenish-
brown
Slow growing, powdery, greenish-
brClub-shaped macroconidia in
clustersown
E. floccosum

25. TREATMENT
Anti fungal drugs
Topical Drugs; Clotrimazole,
Miconazole and Ketoconazole
Oral Drugs ; Griseofulvin,
Terbinafine and
Amphotericin B

26. PREVENTIONS
Keep the skin clean and dry.
Maintain good hygiene will help larger
topical mycoses.
Wash after touching other people or
animals.