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
BY FAR THE MOST COMMON FUNGAL DISEASE
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 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 Outcomes10. 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►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
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 MalasseziaMicroscopy shows clusters of furfur on Dixons agarround 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/Seborrheicdermatitis; (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. 2http://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 PiedraPiedraia 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 mycosesThe 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 topyriform and found in grape like clusters. Spiral hyphaeare often present.Macroconidia are multiseptate, club-shaped and oftenabsent.Lab tests: hair perforation test positive, ureasepositive, growth at 37°C.Infection is typically found on the feet, hands, or groin,but can also be associated with inflammatory lesions ofthe 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.
MicrosporumColony growth is rapid, downy,becoming powdery to granular,cream, tawny-buff, or pale cinnamonon the surface with a beige to red-brown reverse.Microconidia are moderately abundant and club-shaped.Macroconidia are abundant, ellipsoidal to fusiform, sometimesverrucose, 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 ismore frequently isolated from the soil and from the fur of smallrodents.
EpidermophytonColony growth is slow, powdery,with a yellow to khaki surface colorand chamois to brown reverse.Macroconidia are club shaped, with thin smooth walls andcan be solitary or grouped in clusters. Chlamydospores areoften 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 thegroin or feet.
Dermatophytes Differentiation Table:Name of fungal Hair Urease Growth Macro-conidia Micro-conidia Distinguishingspecies Perforation Test at 37°C Characteristics TestTrichophyton Negative Negative Positive Pencil Club shaped to Red reverse pigmentrubrum shaped/cigar pyriform, along the Hair perf. test neg. shaped sides of the hyphae Club shaped microconidiaTrichophyton Positive Positive Positive Club shaped when Numerous Round microconidia in present grape like clustersmentagrophytes Unicellular to round Spiral hyphae in grape like clustersTrichophyton Usually (-) Positive Positive Cylindrical to cigar Numerous, varying Microconidia varying in shaped and in shape and size, shape and sizetonsurans Occasionally + sinuous, if present club shaped to Growth enhanced by balloon shaped thiamineTrichophyton Negative Negative Positive “Rat-tailed” if Rare or Absent Chlamydospores in present chainsverrucosum Chlamydospores in chains typically seen Growth better on media with thiamine and inositolEpidermophyton Negative Positive Positive Club shaped, often Absent Khaki colored colony with in clusters brown reversefloccosum Microconidia absentMicrosporum Positive Positive NA Fusoid, thick, Typically absent Fusoid, rough walled rough walled with macroconidia withcanis Club shaped if recurved apex recurved apex presentMicrosporum Positive Positive NA Ellipsoidal to Moderately Thin walled macroconidiagypseum fusiform, thin, abundant Club Tawny-buff granular Rough walled shaped colony
Diagnosis - DermatophytesDirect ExaminationTreating 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 - manTrichophyton 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 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 of ringworm infections are called different names on basis of location of infection sites1. Tinea capitis - ringworm infection of the head, scalp, eyebrows, eyelashes2. 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 nails6. Tinea barbae - ringworm infection of the beard7. Tinea manuum - ringworm infection of the hand8. Tinea pedis - ringworm infection of the foot (athletes 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 capitisRingworm of the head, scalp, eyebrows, eyelashes – zoophilic and anthrophilic speciesSings 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 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 invasionKOH 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 corporisRingworm infection of body - trunk, face, neck and limbs (smooth skin) - zoophylic and anthrophilic speciesSigns 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 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 crurisRingworm 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 (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 ItchScrape at growing edge wheremycelium is causing inflammation Stained KOH MOUNT
Tinea UnguiumRingworm 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 Pedis (Athlete’s foot)Adult disease-fungal infection characterised by itching, burningand stinging of interdigital webs (releasing of clear fluid) - 4thand 5th toes are most common – anthrophilic speciesSigns 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)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
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)
Diagnosis of DermatophytosisI. ClinicalAppearanceWood lamp (UV, 365 nm)II. LabA. Direct microscopic examination(10-25% KOH)Ectothrix/endothrix/favic hairB. Culture Mycobiotic agar Sabouraud dextrose agar
Identification of DermatophytesA. Colony characteristicsB. Microscopic morphology Macroconidium MicroconidiumMicrosporum---- fusifor--- (+)Epidermophyton clavate----- (-)Trichophyton-- - (few)cylindrical/ --- (+) clavate/fusiform single, in clusters
Diagnosis of DermatophytosisC. 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/lightThis light is a long-waveultraviolet rays passing through aglass containing nickel oxide.Certain fungi fluoresce whenexamined by Wood’s light e.g.Microsporum canis gives brightgreen fluorescence andTrichophyton schoenleinii givesdull green fluorescence. Infected hair fluoresces bright green, beads on hairs contrasting strongly with dark field.
Fluorescing hair (under Woodslamp) Ectothrix and EndothrixSeen in dogs and cats infectedwith some dermatophytes
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 mountDermatophytosis: KOH mount