tinea – the dermatophytes

8/4/2019 Tinea The Dermatophytes

1/67

Dr. James


2/67

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


3/67

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)


4/67

Classical Ringworm Lesion


5/67

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


6/67

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.


7/67

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


8/67

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)


9/67

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


10/67

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


11/67

Tinea Capitis Ringworm of the scalp, eyebrows and eyelashes


12/67

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


13/67

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


14/67

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


15/67

Tinea Capitis


16/67

Tinea CapitisSeborrheic type :

Common resembles dandruff

Close exam for broken hairs, black dots Lymphadenopathy

Frequently negative KOH (70%)

Culture often necessary for DX


17/67

Tinea CapitisKerion :

Inflamed, deep boggy swelling and tender.

M. Canis common etiologySystemic symp: Fever, Lymphadenopathy.

Scaring alopecia may occur

KOH often negativeMay look bacterial


18/67

Tinea Capitis - Kerion


19/67

Tinea CapitisPustular :

Discrete pustules and crusted areas

No significant hair loss or scale

Often KOH negative

Frequently treated as bacterial at first


20/67

Tinea Capitis


21/67

TINEA CAPITIS


22/67

Tinea barbae


23/67

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/Dermatophyte


24/67

Tinea barbae


25/67

Tinea Pedis

Athletes Foot Infection


26/67

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


27/67

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.


28/67

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.


29/67

Tinea Pedis

Differential:

Eczema, contact dermatitis

Psoriasis.

Erythrasma and Candida (esp in web spaces.)

Pitted keratolysis


30/67


31/67


32/67

Tinea manuum


33/67

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.


34/67

Tinea manuum


35/67


36/67


37/67


38/67

Tinea Unguium Nail Infection

( (Onychomycosis)


39/67

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


40/67

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


41/67

Candidaisis of nail


42/67

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


43/67

Tinea Corporis - body ringworm


44/67

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


45/67

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).


46/67


47/67

Tinea Corporis


48/67

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


49/67

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),


50/67

Tinea Cruris


51/67

Tinea Cruris


52/67


53/67

Tinea favosa

Ringworm infection of the scalp(crusty hair)


54/67

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)


55/67

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


56/67

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


57/67

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.


58/67

Treatment

Topical

Miconazole, clotrimazole, econazole, terbinafine...

Oral

Griseofulvin

Ketaconazole

Itraconazole

Terbinafine


59/67


60/67

QUIZ..


61/67

Tinea pedis


62/67

Tinea unguium


63/67

Tinea corporis


64/67

Tinea cruris


65/67

Tinea barbae


66/67


67/67

tinea – the dermatophytes

Documents