skin and soft tissues infections

Skin and soft tissues infections

Classification of mycosesSuperficial and cutaneous

Subcutaneous

Deep (systemic)

Superficial mycoses

Caused by fungi living as

saprophytes

Hair, dead skin and lipids secretions

They don’t provoke any immune

response

No pain or itching

Pityriasis versicolor

Common, mild and chronic infection of stratum corneum

World-wideMore common in tropics and sub-

tropics In temperate regions more common

during summer

Pityriasis versicolor Caused by Malassezia

yeast, which is lipophilic dimorphic

fungus

KOH Parker ink staining

Tinea nigraTypical brown to black, non-scaling macules on

the palmar aspect of the hands. 

Note: there is no inflammatory reaction

Cutaneous mycoses Infections in the living parts of the body:

Skin Hair and nail Mucocutaneous membranes Genitalia

Tow types can be recognized Dematophytes infections Non-dermatophytes infections

Dematophytes infections(dematophytosis)

Ringworm (hair and skin)

Favus (hair)

Onychomycosis (nail)

Dermatophytosis(=Tinea = Ringworm)

Infections of the skin, hair and nails

due to a group of related

filamentous keratinophilic fungi

called dermatophytes

Dermatophytes

Microsporum Hair, skinEpidermophyton Skin, nailTrichophyton Hair, skin, nail

Digest keratin by their keratinasesResistant to cycloheximide

Epidemiology and natural habitat

Some have a world-wide distributionSome are restricted to particular

regions About 10 species are common

causes of human infectionClassified into three groups

depending on their usual habitat

Anthropophilic

Human is usual host T. rubrum (foot & nail infections)

E. floccosum (foot & nail infections)

T. tonsurans (scalp infections)

M. audouinii (scalp infections)

Geophilic

Normal habitat is soilCan cause infections in both humans

and animals Microsporum gypseum

Zoophilic

Often associated with a particular

animal

Microsporum canis: cats and dogs

Trichophyton verrucosum: horse and

cattle

Dermatophytosis

Skin: Circular dry lesions Slightly raised red scaly margins Surrounded by red itchy skin Fungus remain restricted to stratum corneum Metabolites provoke inflammation

Hair: Typical lesions → scarring + alopecia

Nail: Thickened, deformed, fragile, discolored Sub-ungual debris accumulation

Dermatophytosis clinical classification

Infection is named according to the anatomic location involved

Clinical manifestation (1) Ringworm

Tinea pedis (athlete's foot) Tinea manuum (hands) Tinea corporis (trunk, neck and back) Tinea cruris (hairy skin around the genitilia) Tinea barbae (hairy skin in the face) Tinea capitis (scalp and eyebrows)

Clinical manifestation (2)

Favus (scalp)

Onychomycosis (nail)

Athlete's foot

(Tinea pedis )

Tinea pedis

Tinea manuum

Tinea manuum

Tinea manuum

Tinea corporis caused by M. canisfollowing contact with infectious cat

Tinea corporis

Tinea of the groin showing typical erythematous lesions on the inner thighs

Tinea of the buttocks

Tinea cruris

Tinea barbae

Tinea capitis caused by M. canisfollowing contact with infectious cat

Tinea capitis showing extensive hair losscaused by M. canis

Favus and OnychomycosisFavus

Special form of tinea capitis

Onychomycosis Fungal infection of nail The term "tinea unguium" is used specifically to

describe dermatophytic onychomycosis

Favus

Tinea capitis showing alopecia

Tinea of the nails caused by T. rubrum

Laboratory diagnosis

50 % of suspicious materials may be negative Hyphae and/or arthrospores is diagnostic Culture is more reliable:

Determined species Source of infection Can be positive even if direct examination is

negative

Hyphal elements seen in skin scraping preparation

Management

Dependant on the clinical setting

Topical or oral antifungal

Infection Recommended Alternative

Tinea unguium[Onychomycosis]

Terbinafine 250 mg/day6 weeks for finger nails,12 weeks for toe nails.

Itraconazole 200 mg/day/3-5 months or 400 mg/day for one week per month for 3-4 consecutive months. Fluconazole 150-300 mg/ wk until cure [6-12 months].Griseofulvin 500-1000 mg/day until cure [12-18 months].

Tinea capitis

Griseofulvin 500mg/day[not less than 10 mg/kg/day]until cure [6-8 weeks].

Terbinafine 250 mg/day/4 wks.Itraconazole 100 mg/day/4wks. Fluconazole 100 mg/day/4 wks

Tinea corporis

Griseofulvin 500 mg/day untilcure [4-6 weeks], often combined with a topicalimidazole agent.

Terbinafine 250 mg/day for 2-4 weeks.Itraconazole 100 mg/day for 15 days or 200 mg/day for 1week.Fluconazole 150-300 mg/week for 4 weeks.

Tinea cruris Griseofulvin 500 mg/dayuntil cure [4-6 weeks].

Terbinafine 250 mg/day for 2-4 weeks.Itraconazole 100 mg/day for 15 days or 200 mg/day for 1week.Fluconazole 150-300 mg/week for 4 weeks.

Tinea pedis Griseofulvin 500mg/dayuntil cure [4-6 weeks].

Terbinafine 250 mg/day for 2-4 weeks.Itraconazole 100 mg/day for 15 days or 200 mg/day for 1week.Fluconazole 150-300 mg/week for 4 weeks.

Chronic and/orwidespread

non-responsivetinea.

Terbinafine 250 mg/dayfor 4-6 weeks.

Itraconazole 200 mg/day for 4-6 weeks.Griseofulvin 500-1000 mg/day until cure [3-6 months].

Oral management options

Non-dermatophytes cutaneous infections

Onychmycosis IntertrigoMucocutaneous candidiasis

Thrush Vulvo-vaginitis

Intertrigocaused by Candida albicans

Red macerated rash under pendulous breasts is a common presentation of cutaneous candidiasis

Candida diaper dermatitis

This condition should not

be considered a primary

Candida infection as it

preceded by an irritant

dermatitis

Subcutaneous Mycoses

Skin, subcutaneous tissues, fascia and bone

LocalizedTraumaMore in tropicsMycetoma, chromomycosis and

sporotrichosis

Mycetoma

Mycetoma

SporotrichosisA 60-year-old woman developed multiple subcutaneous

nodules and abscesses on her right hand and forearm 7 days after finger thorn prick

Sporotrichosis

ClassicalChromoblastomycosis:Fonsecaea pedrosoi

De Hoog, Centraalbureau voor Schimmelcultures

Nodulose chromoblastomycosis(Senegal): Fonsecaea pedrosoi

De Hoog, Centraalbureau voor Schimmelcultures

Management

Difficult

Surgical excision

Itraconazole and other antifungal