Superficial & dermatophyte 2

SUPERFICIAL MYCOSES

A. Akhtar Ahmed
Department of Microbiology
Ibrahim Medical College, Shahabagh, Dhaka

Elias Fries,
Sweden
(1794-1878)
“Father of
Mycology"

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

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.

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

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

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

Superficial Mycoses
And Dermatophytes

Malassezia furfur
Exophiala werneckii
Piedraia hortae
Superficial Mycoses
Trichosporon beigelii

Microsporum
Trichophyton
Epidermophyton Dermatophytes
Candida albicans

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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

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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)

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

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

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

Tinea versicolor

 Sites of Predilection:
 Upper trunk
 Face
 Forehead
 Back of the hands
 Legs
 May itch if it is inflammatory

Sites of Pityriasis versicolor and showing
hyperpigmented lesions

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”

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)

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.

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

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)

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

Tinea nigra

 Micr.: Septate hyphae and yeast
cells (brown in color)
 Culture: Black colonies

 Treatm.: Topical salicylic acid,
tincture of iodine

Typical brown to black, non-scaling macules
on the palmar aspect of the hands.
Note there is no inflammatory reaction.

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http://www.mycology.adelaide.edu.au/Mycoses/Superficial/Tinea_nigra/index.h

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

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

Black Piedra

Piedraia hortae forms a hard superficial pigmented nodule
around the hair shaft

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

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

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

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).

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

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.

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

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.

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.

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.

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.

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.

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

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.

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

DERMATOPHYTES

 Digest keratin by their
keratinase
 Resistant to cycloheximide
 Classified into three groups
depending on their usual habitat

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…

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)

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 )

Clinical manifestations of
Dermatophytosis
 Skin: Circular, dry, erythematous,
scaly, itchy lesions
 Hair: Typical lesions, ”kerion”,
scarring, “alopecia”
 Nail: Thickened, deformed, friable,
discolored nails, subungual debris
accumulation
 Favus (Tinea favosa)

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)

**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

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

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

**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.

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

Inflammatory and Non-inflammatory
Tinea Capitis

Tinea Manuum (hand fungal infection)

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

Tinea corporis

 Sites of predilection:
 Neck
 Upper and lower
extremities
 Trunk

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”

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

Tinea corporis
 Diagnosis:
 KOH (potassium
hydroxide) test
 Skin lesion biopsy

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

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

Tinea cruris
 Etiology:  Predisposing factor:
 T. rubrum  Heat and humidity
 T. mentagrophytes  Tight jockey shorts
 E. floccosum

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

Tinea Cruris – Jock Itch

Scrape at growing edge where
mycelium is causing inflammation
Stained KOH
MOUNT

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

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

Tinea Pedis (Athlete’s foot)

Tinea pedis (athlete’s
foot)
Characteristics:
 Fungal infections of the
feet
 Common in men
 Primary lesions:
 Maceration
 Slight scaling
 Occasional
vesiculation and
fissures
 Hyperhidrosis

Tinea pedis
 Etiology:  Diagnosis:
 T. rubrum – most  Potassium hydroxide
frequent causative fungus (KOH)
 T. mentagrophytes  Sabouraud’s glucose agar
 E. floccosum or Mycosel gel

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

DERMATOPHYTOSIS
Transmission
 Close human contact
 Sharing clothes, combs, brushes,
towels, bed sheets... (Indirect)
 Animal-to-human contact
(Zoophilic)

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.

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.

Id reactions to fungal infection under foot.
(No fungus seen or cultivatable from id)

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

Identification of Dermatophytes

A. Colony characteristics
B. Microscopic morphology
Macroconidium Microconidium
Microsporum---- fusifor--- (+)
Epidermophyton clavate----- (-)
Trichophyton-- - (few)cylindrical/ --- (+)
clavate/fusiform
single, in clusters

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

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.

Fluorescing hair (under Wood's
lamp) Ectothrix and Endothrix

Seen in dogs and cats infected
with some dermatophytes

DERMATOPHYTOSIS
Treatment

 Topical
Miconazole, clotrimazole,
econazole, terbinafine...
 Oral
Griseofulvin
Ketaconazole
Itraconazole
Terbinafine

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

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

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

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

KERATOMYCOSIS

 Micr.: Hyphae in corneal
scrapings
 Treatm.: Surgery (keratoplasty)
Topical pimaricin
Nystatin
Amphotericin B

Malassezia furfur: KOH mount

Dermatophytosis: KOH mount

Superficial & dermatophyte 2

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