SUPERFICIAL MYCOSES

A. Akhtar AhmedDepartment of MicrobiologyIbrahim Medical College, Shahabagh, Dhaka

Elias Fries, Sweden

(1794-1878)“Father of Mycology"

OutlineOutline 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 – Dermatophytes – Trichophyton, Microsporum &

Epidermophyton Dermatophytes Differentiation TableDermatophytes Differentiation Table Classification of Dermatophytes on source Clinical classification of dermatophytosis Clinical manifestation of dermatophytosis – Dermatophytide (ide or id) reactions Diagnosis of dermatophytosis

Learning OutcomesLearning OutcomesLearners 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 mycosesSuperficial 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 mycosesSuperficial 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 Black piedra - Piedraia hortae White piedra - Trichosporon beigelii Pityriasis versicolor - Malassezia furfur Tinea nigra - Exophiala werneckii

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Malassezia furfur Exophiala werneckiiPiedraia hortaeTrichosporon beigelii

MicrosporumTrichophytonEpidermophyton

Superficial Mycoses

Dermatophytes

Superficial Mycoses And 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

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 versicolorCharacteristics: 

Occur at any age Higher sebaceous

activity (i.e., adolescence and young adulthood)

Oily skin

Predisposing factors: Malnutrition Burns Corticosteroid

therapy Immunosuppression Depressed cellular

immunity Excess heat Humidity

Tinea versicolorClinical

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 mal es

Associated with increased sweating Lesions fluoresce greenish yellow in Wood’s light Treatm.: Topical selenium sulphide

Oral ketaconazoleOral 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 versicolorDiagnosis:

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 furfur on Dixon's agar(contains glycerol

mono-oleate)

Microscopy shows clusters of round yeasts with

filaments by KOH mount of scraping

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 RequiredThree 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.

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

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

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 - DermatophytesIntroduction - 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 = 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).

DermatophytesDermatophytes

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

TrichophytonColony 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.

EpidermophytonColony 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.

Name of fungal species

Hair Perforation Test

Urease Test

Growth at 37°C

Macro-conidia Micro-conidia Distinguishing Characteristics

Trichophyton rubrum

Negative Negative

Positive Pencil shaped/cigar

shaped

Club shaped to pyriform, along the sides of the

hyphae

Red reverse pigment

Hair perf. test neg.

Club shaped microconidia

Trichophyton mentagrophytes

Positive Positive Positive Club shaped when present

Numerous

Unicellular to round in grape

like clusters

Round microconidia in grape like clusters

Spiral hyphae

Trichophyton tonsurans

Usually (-)

Occasionally +

Positive Positive Cylindrical to cigar shaped

and sinuous, if present

Numerous, varying in shape

and size, club shaped to

balloon shaped

Microconidia varying in shape and size

Growth enhanced by thiamine

Trichophyton verrucosum

Negative Negative

Positive “Rat-tailed” if present

Rare or Absent

Chlamydospores in chains

typically seen

Chlamydospores in chains

Growth better on media with thiamine

and inositol

Epidermophyton floccosum

Negative Positive Positive Club shaped, often in clusters

Absent Khaki colored colony with brown reverse

Microconidia absent

Microsporum

canis

Positive Positive NA Fusoid, thick, rough walled with recurved

apex

Typically absent

Club shaped if present

Fusoid, rough walled macroconidia with

recurved apex

Microsporum gypseum

Positive Positive NA Ellipsoidal to fusiform, thin, Rough walled

Moderately abundant Club

shaped

Thin walled macroconidia

Tawny-buff granular colony

Dermatophytes Differentiation Table:

Spores of Dermatophytes

Diagnosis - Diagnosis - DermatophytesDermatophytesDirect 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 dogsMicrosporum nanum: swine Trichophyton verrucosum: horse and swine…

Clinical Classification ofDermatophytosis

Infection is named according to the

anatomic location involved:a. Tinea barbae e. Tinea pedis

(Athlete’s foot)b. Tinea corporis f. Tinea manuumc. Tinea capitis g. Tinea unguiumd. Tinea cruris

(Jock itch)

DermatophytosisPathogenesis 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 ofDermatophytosis

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

sites1. 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**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

KERIONKERION

Tinea capitisRingworm 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 presentDifferential 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**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.

KOH mount of infected hairs showing ectothrix invasion by M. gypseum.

KOH mount of an infected hair showing anendothrix invasion caused by T. tonsurans3

Fungal infection of hairs showing ectothrix and endothrix invasion

Inflammatory and Non-inflammatory Tinea Capitis

Tinea Barbae Tinea Faciei

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 lesionsDifferential diagnosis - dermatitis

Tinea corporisTinea 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:

Any age Common in warm

climates Most common in

children Excessive

perspiration - most common predisposing factor

Etiology: Microsporum canis T. rubrum T. mentagrophytes

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 yeastalso.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 togetherRisk factors? – Obesity and wearing tight-fitting or

wet clothing or undergarments

Tinea cruris Tinea cruris (Jock itch, crotch (Jock itch, crotch itch )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:

T. rubrum T. mentagrophytes E. floccosum

Predisposing factor: Heat and humidity Tight jockey shorts

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 pustulesDiagnosis:•KOH (potassium hydroxide) test •Culture

Tinea CrurisTinea Cruris – Jock Itch – Jock Itch

Scrape at growing edge where mycelium is causing inflammation

Stained KOH MOUNT

Tinea Unguium

Ringworm of nails- anthrophilic speciesCharacteristic 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 Unguium: Nail Tinea Unguium: Nail InfectionInfection

Guidelines for referral

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:

MacerationSlight scalingOccasional

vesiculation and fissures

Hyperhidrosis

Tinea pedis Etiology:

T. rubrum – most frequent causative fungus

T. mentagrophytes E. floccosum

Diagnosis: Potassium hydroxide

(KOH) Sabouraud’s glucose

agar or Mycosel gel

Tinea pedisProphylaxis:

Dry the toes thoroughly after bathing

Antiseptic powder Tolnaftate powder

(Tinactin powder) or Zeasorb medicated powder

Plain talc, cornstarch, or rice powder

DERMATOPHYTOSISTransmission

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)

Dermatophytid Reaction

Diagnosis of Dermatophytosis

I. ClinicalAppearanceWood lamp (UV, 365 nm) II. Lab A. Direct microscopic examination(10-25% KOH)Ectothrix/endothrix/favic hairB. Culture Mycobiotic agar Sabouraud dextrose agar

Identification of Dermatophytes

A. Colony characteristicsB. Microscopic morphology Macroconidium

MicroconidiumMicrosporum---- 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

DERMATOPHYTOSISTreatment

Topical Miconazole, clotrimazole,

econazole, terbinafine...

OralGriseofulvinKetaconazoleItraconazoleTerbinafine

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