Basic Civil Engineering first year Notes- Chapter 4 Building.pptx
Superficial & dermatophyte 2
1. SUPERFICIAL MYCOSES
A. Akhtar Ahmed
Department of Microbiology
Ibrahim Medical College, Shahabagh, Dhaka
2. Elias Fries,
Sweden
(1794-1878)
“Father of
Mycology"
3. Outline
Learning outcome
Introduction to Superficial Mycoses
Classification of Superficial Mycoses and Dermatophytes
Superficial mycoses - Pityriasis versicolor, Seborrheic
Dermatitis, Tinea Nigar (plamalis), Black Piedra and White
Piedra
Introduction to Dermatophytes
Dermatophytes – Trichophyton, Microsporum &
Epidermophyton
Dermatophytes Differentiation Table
Classification of Dermatophytes on source
Clinical classification of dermatophytosis
Clinical manifestation of dermatophytosis –
Dermatophytide (ide or id) reactions
Diagnosis of dermatophytosis
4. Learning Outcomes
Learners will be able to solve following problem after attending this
session.
1. Classify superficial fungus. Enumerate superficial fungal diseases.
2. What are the dermatophytes and dermatophytosis?
3. Give lab diagnosis of superficial fungal infection.
4. How would you diagnose in lab a case of suppurative fungal skin
infection?
5. How would you diagnose in lab a case of a ring worm?
6. How would you diagnose in lab a case of fungal nail infection?
7. Write down the lab diagnoses of tinea capitis /pedis (athlete’s foot)/
unguium
(onychomycoses)/manum/corporis/cruris(jock itch)/barbae(facial tinea).
8. How will you collect specimen for diagnosing a case of tinea capitis
/pedis (athlete’s foot)/unguium
(onychomycoses)/manum/corporis/cruris (jock itch)/barbae (facial
tinea).
9. Classify dermatophytes.
5. Learning Outcomes
10. Write in detail about a lab test that can be carried out in thana health
complex to diagnose a case of dermatophytoses.
11. What is dermatophytid reaction/ “id” reaction?
12. Write in short about pathogenesis of ring worm.
13. Write down the clinical features/pathogenesis/lab diagnosis of
Pityriasis versicolor/Saborrheic dermatitis.
14. Short Note –
i) Tinea nigra
ii) White/black piedra
iii) Onychomycoses/ otomycoses/mycotic keratitis
iv) Oral/vaginal Candidiasis/moniliasis/pseudomembranous
candidiasis/chronic mucocutaneous candidiasis
6. Introduction
Superficial mycoses
Mycoses of skin, hair, and nails are grouped according
to which layers are affected and clinical
manifestations
Superficial mycoses are fungal infections of the
outermost keratinized (cornfield?) layers of the skin
or hair shaft resulting in essentially no pathological
changes. No cellular immune response is elicited &
minimal humoral host response - IgA
These mycoses are largely cosmetic involving skin
pigmentation or forming nodules along distal hair
shafts – often asymptomatic & host is unaware
7. Superficial mycoses
Superficial mycoses are limited to the outermost
layers of the skin and hair.
Superficial Mycoses include the following fungal
infections and their etiological agent:
Black piedra - Piedraia hortae
White piedra - Trichosporon beigelii
Pityriasis versicolor - Malassezia furfur
Tinea nigra - Exophiala werneckii
9. Superficial mycoses
►Tinea versicolor causes mild scaling, mottling
of skin
►White piedra is whitish or colored masses on
the long hairs of the body
►Black piedra causes dark, hard concretions on
scalp hairs
White & black piedra
►Transmission is often mediated by shared hair brushes or combs
►Several members of a family are usually infected at the same time
►Infected areas must often be shaved to remove the fungi
9
10. Pityriasis versicolor
Normal flora of the superficial epidermis and
clusters around the openings of hair follicles
Saprophytic on normal skin of trunk, head, neck
and appears in highest numbers in areas with
increased sebaceous activity
Systemic infection (parenteral lipid solution)
Superficial chronic infection of Stratum
corneum
Etio: Malassezia furfur (Pityrosporum
orbiculare) - Lipophilic yeast
• Micr.: Short hyphae, yeast cells
• Culture: Yeast (suppl.: olive oil)
11. Tinea versicolor
Characteristics: Predisposing factors:
Occur at any age Malnutrition
Higher sebaceous activity Burns
(i.e., adolescence and Corticosteroid therapy
young adulthood) Immunosuppression
Oily skin
Depressed cellular
immunity
Excess heat
Humidity
12. Tinea versicolor
Clinical presentation:
Multiple small, circular
macules
Red to fawn-colored
macules, patches, or
follicular papules
Hypopigmented lesions
Tan to dark brown
macules and patches
13. Clinical features
The lesions are small hypopigmented or
hyperpigmented macules
Most common site : back, underarm, upper arm,
chest, neck and occasionally on face
Most common in adolescent and young adult males
Associated with increased sweating
Lesions fluoresce greenish yellow in Wood’s light
Treatm.: Topical selenium sulphide
Oral ketaconazole
Oral itraconazole
14. Tinea versicolor
Sites of Predilection:
Upper trunk
Face
Forehead
Back of the hands
Legs
May itch if it is inflammatory
16. Tinea versicolor
Diagnosis:
Wood’s light
yellowish or brownish
extent of involvement
or the achievement of a
cure
KOH
short, thick fungal
hyphae and large
numbers of variously
sized spores
“spaghetti and meatballs”
17. Culture of Malassezia
Microscopy shows clusters of furfur on Dixon's agar
round yeasts with filaments by (contains glycerol mono-
KOH mount of scraping oleate)
18. Seborrheic Dermatitis
More common than psoriasis
Regions with a high density of sebaceous glands, (scalp,
forehead (especially the glabella), external auditory canal,
retroauricular area, nasolabial folds & beard skin)
Not a disease of the sebaceous glands
Macules and papules with extensive scaling and crusting
Fissures- behind the ears
Dandruff is the common
Infants-presents as cradle cap
also be part of Leaner disease (with diarrhoea and failure to thrive)
It is more often seen in AIDS, CHF, Parkinson disease, and in
immunocompromised premature infants.
19. Seborrheic Dermatitis
Features
Both spongiotic dermatitis and psoriasis
Parakeratosis containing neutrophils and serum are
present at the ostia of hair follicles (so-called follicular
lipping)
HIV-apoptotic keratinocytes and plasma cells
Etiology: Three Factors are Required
Yeast fungus - Malassezia furfur
Sebum
Susceptible individuals
20. Range of visible flakes along dandruff (altered stratum corneum)
/Seborrheic dermatitis disease spectrum.
(a) ASFS=20, mild dandruff; (b) ASFS=30, moderate dandruff/Seborrheic
dermatitis; (c) ASFS=42, severe dandruff/Seborrheic dermatitis.
(ASFS = adherent scalp flaking scale)
21. Tinea Nigar (plamalis)
Superficial chronic infection of Stratum
corneum located most often on the palms
Caused by a black yeast Hortae (Exophiala)
werneckii (pigmented)
Clinical findings: Brownish non scaling
macules and asymtoptomatic on palms,
fingers, face
Most often in tropical or semitropical areas
of Central and South America, Africa, and
Asia
22. Tinea nigra
Micr.: Septate hyphae and yeast
cells (brown in color)
Culture: Black colonies
Treatm.: Topical salicylic acid,
tincture of iodine
23. Typical brown to black, non-scaling macules
on the palmar aspect of the hands.
Note there is no inflammatory reaction.
2
http://www.mycology.adelaide.edu.au/Mycoses/Superficial/Tinea_nigra/index.h
24. Black Piedra
Asymptomatic fungal infection of the scalp
hair shafts
Caused by Piedraia hortae
Clinical findings: Discrete, hard, dark
brown to black nodules on the hair
Frequent in tropical areas
25. Black piedra
Micr. Septate pigmented hyphae,
and asci; unicellular and fusiform
ascospores with polar filament(s)
Culture: Brown to black colonies
Treatm.: Topical salicylic acid,
azol cremes
27. White piedra
Asymptomatic fungal infection of the
hair shafts
Caused by Trichosporon beigelii (yeast)
Produces light-colored, soft nodules that
are attached to the hairs and may cause
the hair shafts to break
Fungal infection of facial, axillary or
genital hair
Frequent in tropical and temperate zones
29. White piedra
Clinical findings: Soft, white to
yellowish nodules loosely
attached to the hair
Micr.: Intertwined septate
hyphae, blasto- and arthroconidia
Culture: Soft, creamy colonies
Treatm.: Shaving, azoles
30. Introduction - Dermatophytes
Cutaneous fungi are called Dermatophytes which are
keratinophilic fungi – they possess keratinase allowing them to
utilize keratin as a nutrient & energy source
They infect the keratinized (horny) outer layer of the scalp,
glabrous skin, and nails causing tinea or ringworm by secreting
keratinase- which degrades keratin with varied clinical
manifestations and are caused by species of the fungal genera
Trichophyton, Epidermophyton, and Microsporum (in order of
commonality).
Although no living tissue is invaded (keratinized stratum only
colonized) the infection induces an allergic and inflammatory
eczematous response in the host
Lesions on skin and sometimes nails have a characteristic circular
pattern that was mistaken by ancient physicians as being a worm
down in the tissue
These lesions are still today called ringworm infections even
though the etiology is known to be a fungus rather than a worm
31. Dermatophytes = Skin Plants
Fungal agents of skin are called dermatophytes -
"skin plants". Three important anamorphic genera,
i.e., Microsporum, Trichophyton, and Epidermophyton
are involved in ringworm.
Dermatophytes are keratinophilic - "keratin loving".
Keratin is a major protein found in horns, hooves,
nails, hair, and skin.
Ringworm - disease called ‘herpes' by the Greeks,
and by the Romans ‘tinea' (which means small insect
larvae).
32. Dermatophytes
Dermatophytes are mold fungi which grow in tissues
containing keratin; Thus, they are limited to skin, hair
and nails.
Cellular immune response to the presence of fungi in
the skin evokes an inflammatory response often
described as “ ringworm” or “tinea”
Infections are often classified by the area affected;
such as tinea capitis, tinea pedis, tinea manus, tinea
ungium, etc.
Dermatophytes are diagnosed by finding septate
hypha and asexual (anamorphic) spores in the scraping
of infected tissue.
specific identification of the fungi is made by
culture
33. Cutaneous mycoses
The stratum corneum of the epidermis and its
keratinized appendages are infected.
Classification:
Dermatophytoses are caused by the agents of
the genera Epidermophyton, Microsporum, and
Trichophyton.
Dermatomycoses are cutaneous infections due
to other fungi, the most common of which are
Candida spp.
34. Dermatophytes
Taxonomic classification
They belong to the phylum Deuteromycota (Fungi
Imperfecti)
They are hyaline moulds (transparent / white)
Three genera comprise this group
Microsporum
Trichophyton
Epidermophyton
35. Trichophyton
Colony growth is moderately rapid,
powdery to granular, white to
cream colored on the surface with
a yellowish, brown or red-brown reverse.
Microconidia are numerous, unicellular, round to
pyriform and found in grape like clusters. Spiral hyphae
are often present.
Macroconidia are multiseptate, club-shaped and often
absent.
Lab tests: hair perforation test positive, urease
positive, growth at 37°C.
Infection is typically found on the feet, hands, or groin,
but can also be associated with inflammatory lesions of
the scalp, nails, and beard.
36. Trichophyton
Colony growth is slow to
moderate, downy, white on the
surface with a red to brown reverse.
Microconidia are club-shaped to pyriform and are formed
along the sides of the hyphae.
Macroconidia are pencil-shaped to cigar-shaped.
Lab tests: hair perforation test negative, urease negative,
growth at 37°C.
Infection is typically found on the feet, hands, nails, or groin.
37. Microsporum
Colony growth is rapid, downy to
wooly, cream to yellow on the
surface with a yellow to yellow- orange reverse.
Microconidia are club-shaped but typically are absent.
Macroconidia are fusoid, verrucose, and thick walled.
They have a recurved apex and contain 5-15 cells.
Lab tests: hair perforation test positive and urease
positive.
Infection in humans occurs on the scalp and glabrous skin.
It is also a cause of ringworm in cats and dogs.
38. Microsporum
Colony growth is rapid, downy,
becoming powdery to granular,
cream, tawny-buff, or pale cinnamon
on the surface with a beige to red-brown reverse.
Microconidia are moderately abundant and club-shaped.
Macroconidia are abundant, ellipsoidal to fusiform, sometimes
verrucose, and thin walled. They typically contain 3-6 cells.
Lab tests: hair perforation test positive and urease positive.
Infection in humans is found on the scalp and glabrous skin; it is
more frequently isolated from the soil and from the fur of small
rodents.
39. Epidermophyton
Colony growth is slow, powdery,
with a yellow to khaki surface color
and chamois to brown reverse.
Macroconidia are club shaped, with thin smooth walls and
can be solitary or grouped in clusters. Chlamydospores are
often produced in large numbers.
Microconidia are absent.
Lab tests: hair perforation test negative, urease positive,
growth at 37°C.
Infections are commonly cutaneous, especially of the
groin or feet.
40. Dermatophytes Differentiation Table:
Name of fungal Hair Urease Growth Macro-conidia Micro-conidia Distinguishing
species Perforation Test at 37°C Characteristics
Test
Trichophyton Negative Negative Positive Pencil Club shaped to Red reverse pigment
rubrum shaped/cigar pyriform, along the Hair perf. test neg.
shaped sides of the hyphae
Club shaped microconidia
Trichophyton Positive Positive Positive Club shaped when Numerous Round microconidia in
present grape like clusters
mentagrophytes Unicellular to round Spiral hyphae
in grape like clusters
Trichophyton Usually (-) Positive Positive Cylindrical to cigar Numerous, varying Microconidia varying in
shaped and in shape and size, shape and size
tonsurans Occasionally +
sinuous, if present club shaped to Growth enhanced by
balloon shaped thiamine
Trichophyton Negative Negative Positive “Rat-tailed” if Rare or Absent Chlamydospores in
present chains
verrucosum Chlamydospores in
chains typically seen Growth better on media
with thiamine and
inositol
Epidermophyton Negative Positive Positive Club shaped, often Absent Khaki colored colony with
in clusters brown reverse
floccosum
Microconidia absent
Microsporum Positive Positive NA Fusoid, thick, Typically absent Fusoid, rough walled
rough walled with macroconidia with
canis Club shaped if recurved apex
recurved apex
present
Microsporum Positive Positive NA Ellipsoidal to Moderately Thin walled macroconidia
gypseum fusiform, thin, abundant Club Tawny-buff granular
Rough walled shaped colony
43. Diagnosis - Dermatophytes
Direct Examination
Treating skin and nail scrapings and “snippets” of hair with
potassium hydroxide (KOH dissolves keratin but not chitin -
hyphae) is usually very effective in detecting dermatophyte
hyphae in clinical specimens.
The addition of calcofluor white (1,4 polymer specific
fluorochrome dye) and dimethylsulfoxide (DMSO) to the
KOH and viewing with a fluorescent microscope is
recommended. DMSO is a non-polar surfactant (wetting
agent) which aids in clearing of the keratin by making KOH
more soluble in the sample.
44. DERMATOPHYTOSIS
(=Tinea = Ringworm)
Infection of the skin, hair or nails
caused by a group of keratinophilic
fungi, called dermatophytes
¨ Microsporum Hair, skin
¨ Epidermophyton Skin, nail
¨ Trichophyton Hair, skin, nail
45. DERMATOPHYTES
Digest keratin by their
keratinase
Resistant to cycloheximide
Classified into three groups
depending on their usual habitat
46. Classification of
Dermatophytes on source
Antropophilic - man
Trichophyton rubrum...
Geophilic - soil
Microsporum gypseum...
Zoophilic - animal
Microsporum canis: cats and dogs
Microsporum nanum: swine Trichophyton
verrucosum: horse and swine…
47. Clinical Classification of
Dermatophytosis
Infection is named according to the
anatomic location involved:
a. Tinea barbae e. Tinea pedis
(Athlete’s foot)
b. Tinea corporis f. Tinea manuum
c. Tinea capitis g. Tinea unguium
d. Tinea cruris
(Jock itch)
48. Dermatophytosis
Pathogenesis and Immunity
Contact and trauma
Moisture
Crowded living conditions
Cellular immunodeficiency
(chronic inf.)
Re-infection is possible (but, larger
inoculum is needed, the course is
shorter )
50. Clinical manifestations of ringworm
infections are called different names on
basis of location of infection sites
1. Tinea capitis - ringworm infection of the head, scalp,
eyebrows, eyelashes
2. Tinea favosa - ringworm infection of the scalp (crusty hair)
3. Tinea corporis - ringworm infection of the body (smooth
skin)
4. Tinea cruris - ringworm infection of the groin (jock itch)
5. Tinea unguium - ringworm infection of the nails
6. Tinea barbae - ringworm infection of the beard
7. Tinea manuum - ringworm infection of the hand
8. Tinea pedis - ringworm infection of the foot (athlete's foot)
51. **KERION
Inflammatory reaction of tinea capitis caused by
Microsporum canis or Trichophyton
mentagrophyte
Felt to be a delayed type hypersensitivity reaction to
fungal elements
presented as boggy indurated swellings with crusting and
loose hairs.
Follicles may be seen discharging pus.
In extensive lesions, fever, pain and regional
lymphadenopathy is present
Kerion may be followed by scarring and alopecia in areas
of inflammation and suppuration
53. Tinea capitis
Ringworm of the head, scalp, eyebrows, eyelashes
– zoophilic and anthrophilic species
Sings and symptoms
Round, gray, flaky, semi-bald patches on scalp
Mild inflammatory reaction but may vary from
ltd flakiness to thick, suppurating crust
Broken lustreless hair
Slight itching may be present
Differential diagnosis – Dandruff, Seborrheic
eczema and Psoriasis
54. Tinea Capitis (scalp ringworm)
Three main patterns of hair invasion
Endothrix infections, in which arthrospores are
formed within hair shaft
Ectothrix infections, in which sporulation occurs
outside the hair
Favic, in which the hyphae do not survive well in
hair keratin and cause encrustation or scutula
around the hair follicle
55. **Favus
Tinea favosa - ringworm infection of the scalp
(crusty hair)
It is caused by Trichophyton schoenleinii and
is characterized by the presence of yellowish,
cup-shaped crusts known as scutula. Each
scutulum develops round a hair, which
pierces it centrally. The scutula have a
distinctive mousy odour. Cicatricial alopecia
is usually found in long-standing cases.
56.
57. Fungal infection of hairs showing ectothrix
and endothrix invasion
KOH mount of infected hairs showing KOH mount of an infected hair showing an
ectothrix invasion by M. gypseum. endothrix invasion caused by T. tonsurans3
61. Tinea corporis
Ringworm infection of body - trunk, face, neck and limbs
(smooth skin) - zoophylic and anthrophilic species
Signs and symptoms
Annular lesions with raised borders and central clearing
Exposed surfaces of body
Intense itching-distinguishes it from other ringed
lesions
Differential diagnosis - dermatitis
63. Tinea corporis
Characteristics:
One or more circular,
sharply circumscribed,
slightly erythematous
Dry, scaly
hypopigmented patches
May be slightly elevated
More inflamed and
scaly at the borders
than at the central
part [clearing]
“Ringworm”
64. Tinea corporis
Epidemiology: Etiology:
Any age Microsporum canis
Common in warm T. rubrum
climates T. mentagrophytes
Most common in children
Excessive perspiration -
most common
predisposing factor
66. Tinea cruris
Ringworm of the groin, perineum or perianal area.
inguinal area (jock itch)
Anthrophylic species. Can be caused by yeast
also.
Signs and symptoms
Red lesions confined to groin
Eruption affects groin, perineum, perianal and upper
inner thigh symmetrically
Clearly defined, raised borders
Include pruritis
Discomfort due to inflamed intertriginous tissues rubbing
together
Risk factors? – Obesity and wearing tight-fitting or wet
clothing or undergarments
67. Tinea cruris (Jock itch, crotch itch )
Characteristics:
Tinea of the groin
Occurs often in the summer
months
Common in men
Small erythematous and
scaling or vesicular and
crusted patch
Spreads peripherally and
partly clears in the center
Curved, well-defined border,
particularly on its lower edge
Extend down on the thighs
and backward on the
perineum or about the anus
68. Tinea cruris
Etiology: Predisposing factor:
T. rubrum Heat and humidity
T. mentagrophytes Tight jockey shorts
E. floccosum
69. Tinea cruris
Signs and symptoms:
causes itching or a burning
sensation
red, tan, or brown, with flaking,
peeling, or cracking skin
raised red plaques (platelike areas)
scaly patches with sharply defined
borders that may blister and ooze
advancing edge
redder
more raised
scaly
border turns a reddish-brown
border may exhibit tiny pimples or
even pustules
Diagnosis:
•KOH (potassium hydroxide) test
•Culture
70. Tinea Cruris – Jock Itch
Scrape at growing edge where
mycelium is causing inflammation
Stained KOH
MOUNT
71. Tinea Unguium
Ringworm of nails- anthrophilic species
Characteristic properties
Toenail involvement is common in long-standing tinea
pedis
Fingernail infection –less common
Nails discolour, become thickened and lustreless-debris
accumulates under the free edge
Nails become brittle, may lift and separate from nail bed
Sometimes entire nail is destroyed.
Differential diagnosis - Differential diagnosis
74. Tinea Pedis (Athlete’s foot)
Adult disease-fungal infection characterised by itching, burning
and stinging of interdigital webs (releasing of clear fluid) - 4th
and 5th toes are most common – anthrophilic species
Signs and symptoms
Mild to severe interdigital scaling, maceration with fissures-
most common form
Widespread fine scaling distribution very frequent-scaling
extends to side of foot and lower heel
Vesicular or bullous eruption with large blisters
76. Tinea pedis (athlete’s
foot)
Characteristics:
Fungal infections of the
feet
Common in men
Primary lesions:
Maceration
Slight scaling
Occasional
vesiculation and
fissures
Hyperhidrosis
77. Tinea pedis
Etiology: Diagnosis:
T. rubrum – most Potassium hydroxide
frequent causative fungus (KOH)
T. mentagrophytes Sabouraud’s glucose agar
E. floccosum or Mycosel gel
78. Tinea pedis
Prophylaxis:
Dry the toes thoroughly
after bathing
Antiseptic powder
Tolnaftate powder
(Tinactin powder) or
Zeasorb medicated
powder
Plain talc, cornstarch, or
rice powder
79. DERMATOPHYTOSIS
Transmission
Close human contact
Sharing clothes, combs, brushes,
towels, bed sheets... (Indirect)
Animal-to-human contact
(Zoophilic)
80. Dermatophytide (ide or id)
reactions
It is an allergic rash caused by an inflammatory
fungal infection (tinea) at a distant site. Patients
infected with a dermatophyte may show a lesion,
often on the hands, from which no fungi can be
recovered or demonstrated. It is believed that these
lesions, which often occur on the hand are secondary
to immunological sensitization to a primary (and
often unnoticed) infection located somewhere else
(e.g. feet). These secondary lesions will not respond
to topical treatment but will resolve if the primary
infection is successfully treated.
81. CLINICAL MANIFESTATIONS OF RINGWORM
SYMPTOMS AND TREATMENT
Allergic reactions are sometimes associated with tinea pedis and
other ringworm infections.
Dermatophytide - an "id" allergic reaction.
Toxins get into blood stream and reaches a site other than the site of
infection and blistering occurs on fingers and hands.
In diagnosis, rule out allergic reaction to poison ivy, detergents or
other substances.
During diagnosis, look for tinea (pedis, often) on the body.
Treat the primary site of infection where the antigen is being
produced.
Treat secondary site - blisters.
82. Id reactions to fungal infection under foot.
(No fungus seen or cultivatable from id)
84. Diagnosis of Dermatophytosis
I. Clinical
Appearance
Wood lamp (UV, 365 nm)
II. Lab
A. Direct microscopic examination
(10-25% KOH)
Ectothrix/endothrix/favic hair
B. Culture
Mycobiotic agar
Sabouraud dextrose agar
85. Identification of Dermatophytes
A. Colony characteristics
B. Microscopic morphology
Macroconidium Microconidium
Microsporum---- fusifor--- (+)
Epidermophyton clavate----- (-)
Trichophyton-- - (few)cylindrical/ --- (+)
clavate/fusiform
single, in clusters
86. Diagnosis of Dermatophytosis
C. Physiological tests
In vitro hair perforation test
Special amino acid and vitamin
requirements
Urea hydrolysis
Growth on BCP-milk solids-glucose medium
Growth on polished rice grains
Temperature tolerance and enhancement
87. Wood’s lamp/light
This light is a long-wave
ultraviolet rays passing through a
glass containing nickel oxide.
Certain fungi fluoresce when
examined by Wood’s light e.g.
Microsporum canis gives bright
green fluorescence and
Trichophyton schoenleinii gives
dull green fluorescence.
Infected hair fluoresces bright green, beads on hairs
contrasting strongly with dark field.
88. Fluorescing hair (under Wood's
lamp) Ectothrix and Endothrix
Seen in dogs and cats infected
with some dermatophytes
90. Otomycosis
Fungal infection of the external auditory
canal
Caused by several species of Aspergillus
(most often A. niger), but Candida albicans
is also capable of infecting this site.
The major symptoms are
itching and feeling of
fullness in ear
91. Otomycosis
Risk Factors
Extremely moist, hot environments
Chronic Bacterial Otitis Externa
Symptoms
Significant Ear canal pruritus more than pain
Sensation of ear fullness
Protracted course of Otitis Externa
Signs
Whitish-grey, yellow or black canal exudate
Looks like a Fungal Cave
Lab diagnosis
Potassium Hydroxide (10% KOH) - Fungal hyphae on slide
92. Keratomycosis
(=Mycotic keratitis)
This is an infection on the surface
of cornea with usually follows an
injury to the eye.
Etio: Saprophytic fungi (Aspergillus,
Fusarium, Alternaria, Candida),
Histoplasma capsulatum
Clinical findings: Corneal ulcer
93. Mycotic keratitis (Infection of the
eye)
Infection of the eye caused by many different fungi.
2006 outbreak associated with Fusarium - a mold
growing in contact lens solution held for long periods
Anamorph shows sporulation
Characteristic of Fusarium
94. KERATOMYCOSIS
Micr.: Hyphae in corneal
scrapings
Treatm.: Surgery (keratoplasty)
Topical pimaricin
Nystatin
Amphotericin B
Elias Fries was born 1794 in the village Femsjö in the western part of the province Småland in southern Sweden. According to Fries himself his great interest in fungi started when he as a twelve years old boy came across a magnificent specimen of Hericium coralloides. Already as a school-boy he knew between 300 and 400 species of fungi, to which he gave provisory names. He started his university studies in Lund in 1811 and obtained his doctor's degree there in the year of 1813.
Wood lamp evaluation: Pityriasis versicolor showes blue-green fluorescence of macular dyschromic lesions if irradiated by ultraviolet light with wavelength of approximately 365 nm (black light). However, the test findings may be negative in individuals on antimycotic therapy of those who have recently showered because the fluorescent is water soluble.
Potassium hydroxide preparation: In this test, the physician uses a sharp blade or glass slide to scrape off dead skin cells from the edge of the suspect lesion. The dead skin cells are collected onto a microscope slide, treated with a solution of potassium hydroxide and heated to digest the cells, then examined under a microscope. Sometimes, a dye is added to the potassium hydroxide solution to facilitate visualization of the fungal elements. The physician examines the slide, looking for branching, septated fungal hyphae ( Figure 7 ). This is the most rapid and inexpensive test for dermatophyte fungi, although it occasionally gives false negative results when an individual has already partially treated their ringworm and few fungal cells are still present. Fungal culture: The physician scrapes dead skin cells from the edge of a suspect lesion and sends them to a microbiology laboratory. There, the material is applied to several culture media known to support growth of dermatophyte fungi. By the appearance of the fungal colonies that grow and their growth characteristics, it is possible not only to show that a fungus was present, but also to determine the species. However, this method takes 2-3 weeks to give results and also frequently gives false negative results. Furthermore, it is not usually necessary to know the exact species in order to treat ringworm. Skin biopsy: When a case of ringworm looks very similar to other skin diseases and a potassium hydroxide preparation is negative or inconclusive, physicians will sometimes take a small sample of skin for pathologic examination. Under local anesthesia, a small plug of skin called a punch biopsy is removed and fixed in formalin. Pathologists examine the skin after slicing it into thin sections and staining it with dyes that highlight fungal elements. This method is most expensive (and slightly uncomfortable for the patient), but it does usually give definitive diagnostic results. *Itraconazole (INOX, SPORANOX) *Fluconazole ( SYSCAN, REFLUCAN, ODAFT, FUNZELA, FLUZOCAN, FLUCORAL, FLUCANDIA, DYZOLOR, DIFLUCAN