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Dr. James
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Definition Dermatophytes : 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
Although no living tissue is invaded (keratinized stratum
only colonized) the infection induces an allergic and
inflammatory eczematous response in the host
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Background 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 ringworminfections even though the etiology is known to be afungus rather than a worm
Dermatomycosis
Dermatophytosis (Cutaneous fungal infections)
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Classical Ringworm Lesion
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Three important genera
Trichophyton - Skin, hair, nail
Epidermophyton - Skin, nail Microsporum - Skin, hair
All 3 organisms infect /attack skin
Microsporum does not infect nails
Epidermophyton does not infect hair, they do not invade
underlying non-keratinized tissues
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Poor nutrition hygiene, a tropical climate,deblitatingdisease, atopy, & contact with infected animals,people,or fomites all predispose to fungal infection.
Acute infection tends to be associated with rapiddevelopment of a delayed hypersensitivity tointradermal Trichophyton antigen.
Protective cell mediated immunity is acquired by 80%of patients after primary infection.
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Possible Causes for These Lesions Direct contact with a person who has a fungal
infection
Direct contact with fungi contaminated items(bedding clothes, towels, brushes, etc.)
Direct contact with soil containing fungi
Contact with pets that have a fugal infection
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Possible Etiologic Agents Microsporum audouinii (scalp and body)
Microsporum gypseum (feet, hands, body, scalp, rarely nails)
Micropsorum canis (body in adults, scalp in children,rarely
nails)
Trichophytonmentagrophytes (feet, body, nails, scalp, hands,
groin, does not infect hair)
Epidermophytonfloccosum (groin, body, epidemic athletes
foot, occasionally nails, does not infect hair)
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Clinical Significance
DERMATOPHYTOSIS
Characterized by
Itching, scaling of skin patches that can become
inflamed and weeping
Infection in different sites may be due to differentorganisms but is given one name
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Clinical Classification Tinea corporis - ringworm infection of the body
Tinea pedis - ringworm infection of the foot
Tinea cruris - ringworm infection of the groin
Tinea unguium - ringworm infection of the nails
Tinea capitis - ringworm infection of the head, scalp,
eyebrows, eyelashes Tinea favosa - ringworm infection of the scalp
Tinea manuum - ringworm infection of the hand
Tinea barbae - ringworm infection of the beard
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Tinea Capitis Ringworm of the scalp, eyebrows and eyelashes
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Tinea Capitis Children most common cases. (3-7 yrs.)
Fungus grows into hair follicle
It always requires systemic medication - griseofulvin
Fungistatic agents are somewhat effective(miconazole, clotrimazole)
Alopecia in affected areas
Endothrix invasion of hair shaft
Using a Wood's lamp on hair Microsporum species tend to fluoresce green
Trichophyton species generally do not fluoresce
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Tinea Capitis Presentations of Tinea Capitis
1. Non-inflammatory black dot type
2. Seborrheic type
3. Pustular
4. Inflammatory (Kerion)
5. Favus is a distinctive infection with grey, crustinglesions
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Tinea Capitis Black Dot Type :
Large Areas of Alopecia without inflammation
Mild scaling Occipital lymphadenopathy
Black dot hairs.
At first glance may look like Alopecia areata
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Tinea Capitis
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Tinea CapitisSeborrheic type :
Common resembles dandruff
Close exam for broken hairs, black dots Lymphadenopathy
Frequently negative KOH (70%)
Culture often necessary for DX
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Tinea CapitisKerion :
Inflamed, deep boggy swelling and tender.
M. Canis common etiologySystemic symp: Fever, Lymphadenopathy.
Scaring alopecia may occur
KOH often negativeMay look bacterial
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Tinea Capitis - Kerion
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Tinea CapitisPustular :
Discrete pustules and crusted areas
No significant hair loss or scale
Often KOH negative
Frequently treated as bacterial at first
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Tinea Capitis
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TINEA CAPITIS
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Tinea barbae
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Tinea barbae ("Barber's itch, Ringworm of the beard, and "Tinea
sycosis ) is a fungal infection of the hair.
Tinea barbae is due to a dermatophytic infection around
the bearded area of men. Generally, the infection occurs asa follicular inflammation, or as a cutaneousgranulomatouslesion, i.e. a chronic inflammatory reaction. It is one of thecauses ofFolliculitis.
It is most common among agricultural workers, as thetransmission is more common from animal-to-human thanhuman-to-human. The most common causes are T.mentagrophytes and T. verrucosum
http://en.wikipedia.org/wiki/Dermatophytehttp://en.wikipedia.org/wiki/Beardhttp://en.wikipedia.org/wiki/Inflammationhttp://en.wikipedia.org/wiki/Cutaneoushttp://en.wikipedia.org/wiki/Granulomahttp://en.wikipedia.org/wiki/Folliculitishttp://en.wikipedia.org/wiki/Folliculitishttp://en.wikipedia.org/wiki/Granulomahttp://en.wikipedia.org/wiki/Cutaneoushttp://en.wikipedia.org/wiki/Inflammationhttp://en.wikipedia.org/wiki/Beardhttp://en.wikipedia.org/wiki/Dermatophyte8/4/2019 Tinea The Dermatophytes
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Tinea barbae
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Tinea Pedis
Athletes Foot Infection
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Tinea Pedis Most common of all fungal diseases
30-70% population having been infected at some time
Generally, a diease of adults Causative fungi may be found in shoes, flooring &
shoes. Occlusive footwear is a predisposing factor.
Simple contact is not sufficcient for infection.
Concomitant distruption of skin barrier is necessary. Groups: M > F. Young and middle aged
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Tinea Pedis T. Rubrum most common etiology
4th and 5th toes are most common
Pruritus is the most common symptom
Fissures may be painful & also predisposed to secondarybacterial infection. This is of particular importance inpatients with diabetes, chronic lymphedema, and venousstasis.
Patient is susceptible to reoccurrence
Onychomycosis and tinea pedis associated.
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Tinea pedis may take several forms.
Interdigital scaling & macceration with fissures is mostcommon.
Widespread fine scaling in a moccasin distribution is alsofrequent. The scaling usualy extends up onto the sides ofthe feet & lower heel, where it exhibits a characteristic ,
well defined , polycyclic scaling border.
A highly inflammatory, vesicular, or bullous eruption isuncommon.
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Tinea Pedis
Differential:
Eczema, contact dermatitis
Psoriasis.
Erythrasma and Candida (esp in web spaces.)
Pitted keratolysis
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Tinea manuum
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Tinea manuum Ringworm infection of the hand
Most often a mild erythema with hyperkeratosis &scaling over the palmer surfaces.
Hand infection almost always accompanies footinvolvement.
Unilateral involvement of one hand & both feet is socharacteristic that it immediately suggests this
diagnosis. Inflammatory lesions on the feet may cause a sterile
vesicular id reaction on the hands, which may beconfused with primary fungal infection.
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Tinea manuum
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Tinea Unguium Nail Infection
( (Onychomycosis)
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Onychomycosis Seen in 40% of patients with fungal infections in other
locations.
No Spontaneous remissions
General Appearance: Typically begins at distal nail corner
Thickening and opacification of the nail plate
Nail bed hyperkeratosis
Onycholysis
Discoloration: white, yellow, brown
Edge of the nail itself becomes severely eroded.
Some or all nails may be infected (fingernail
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Onychomycosis4 Types:1. Distal Subungal (most common)
2. White superficial T. Mentagrophytes and molds
Chalky white patches
3. Proximal Subungal May indicate HIV infection
4. Candidaonychomycosis Normally hands with accompanying paronychia
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Candidaisis of nail
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Onychomycosis Differential Diagnosis: (50% of thick nails not classic fungus.)
Allergic contact (nail polish, food items)
Psoriasis
Lichen Planus
Molds
Nail dystrophies (ex nephrogenic)
Drugs
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Tinea Corporis - body ringworm
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Affects all ages , but children are most susceptible.
Most prevalent in hot, humid climate & in rural areas.Tinea corporis resolves itself in several months
Symptoms result from fungal metabolites such astoxin/allergens
Concentric or ring-like lesions on skin
Generally restricted to stratum corneum of the smooth
skin In severe cases these are raised and may become
inflamed
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Typical lesion start as eryththematous macules or
papules that spread outward and develop into annular
& arciform lesions with well defined scaling or
vesicular borders and central clearing.
Most common on face, arms & shoulders.
Transfer form on area to the body to another (from
tinea pedis to tinea corporis).
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Tinea Corporis
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Tinea Cruris Jock Itch More common in men than women.
Infection seen on scrotum and inner thigh, the penis
is usually not infected.
Predisposing factors include persistent perspiration, high
humidity, irritation of skin from clothes, such as tight
fitting underwear or athletic supporters, pre-existing
disease such as diabetes and obesity
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Tinea Cruris Epidemics associated with grouping of people
into tight quarters - athletic teams, troops, shipcrews, inmates of institutions.
Several causes of tinea cruris include T. rubrum(does not normally survive long periods outsideof host), E. flocossum (usually associate withepidemics because resistant arthroconidia in skinscales can survive for years on rugs, shower stalls,locker room floors),
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Tinea Cruris
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Tinea Cruris
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Tinea favosa
Ringworm infection of the scalp(crusty hair)
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Clinical manifestations
Skin: Circular, dry, erythematous, scaly, itchy
lesions
Hair: Typical lesions, kerion, scarring,
alopecia
Nail: Thickened, deformed, friable, discolored
nails, sub-ungual debris accumulation
Favus (Tinea favosa)
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Lab Diagnosis
Nail clippings, skin scrapings, hair /follicle
Placed in sterile container preferably, or between2 slides
No role for swabs
KOH ( 10-25% ) will be added in the lab to dissolvetissue material
Lactophenol blue stain to see if fungal hyphae
seen
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For full identification culture on selective mediarequired
Sabouraud dextrose agar (SDA)
SDA with cycloheximide or chloramphenicol
Low pH 5.0
May require 10-14 days for growth
Macroscopic and microscopic identification ofcolonies
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Prophylactic measures Interdigital areas should be dried thoroughly after
bathing, & talc or antifungal powder should then beapplied.
Footwear should fit well & be nonocclusive (avoidsneakers & plastic or rubber footwear).
Patient with hyperhidrosis should wear absorbentcotton socks & avoid wool and nonwicking syntheticfibres. (control of hyperhidrosis is vital)
Clothes & towels should be changed frequently andlaundered in hot water.
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Treatment
Topical
Miconazole, clotrimazole, econazole, terbinafine...
Oral
Griseofulvin
Ketaconazole
Itraconazole
Terbinafine
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QUIZ..
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Tinea pedis
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Tinea unguium
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Tinea corporis
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Tinea cruris
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Tinea barbae
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