Superficial, Cutaneous and Subcutaneous Fungal Infections
Jarrod Fortwendel, PhDDepartment of Microbiology and Immunology
[email protected] 2142
Nov. 18-22, 2013
Tinea Capitis in an Adult Woman
• 87 yo woman presents to her doctor with a 2-year history of puritic, painful, scaling scalp eruption and hair loss
• Previous treatment included numerous courses of systemic antibiotics and prednisone without success
• Social history: recently acquired several stray cats that she kept inside her home
• Physical exam: numerous pustules throughout the scalp, diffuse erythema, crusting, and scale extending to neck. Extremely sparse scalp hair and prominent posterior lymphadenopathy. No nail pitting.
• Wood light positive• Presumptive diagnosis: Tinea Capitis
Cutaneous (and Superficial) Mycoses
• Infections of the skin, hair, nail
• Invades keratinized layers• Tinea – latin for “worm”• Subgroups of infections
1. Dermatophytoses – “classical ringworm”2. Non-dermatophytic cutaneous mycoses…
“the other superficial group”
The Dermatophytes – Classical ringworm - #1 mould infection
• Epidemiology– Anthropophilic, zoophilic, geophilic– Transmissible– Invade skin, hair and nails– Collectively called “tinea”– 3 major Genera:• Trichophyton• Epidermophyton• Microsporum
The Dermatophytes – Classical ringworm - #1 mould infection
• Epidemiology– Anthropophilic, zoophilic, geophilic– Transmissible– Invade skin, hair and nails– Collectively called “tinea”– 3 major Genera:• Trichophyton• Epidermophyton• Microsporum
T. rubrumT. mentagrophytes
Cause 80-90% of cases worldwide
The Dermatophytes: Pathogenesis
• Virulence factors and pathogenesis:
– Infectious element• Arthroconidia
– Keratin utilization• Keratinophilic and keratinolytic
– Hair invasion/colonization• Endothrix, Ectothrix, Favic
Clinical: Classified by anatomical site affected
• Tinea capitis– Microsporum spp. –
• M. audouinii, gray patch ringworm• M. canis, M. gypseum
• Tinea corporis – point lesion centrifugal spread – anywhere on body from eyebrow and neck “southward”– Trichophyton spp., Epidermophyton, (Also Candida)
• Tinea pedis – cosmopolitan– Trichophyton spp., Epidermophyton
• Tinea unguium– Often as a secondary infected site– Almost any dermatophyte, esp Trichophyton rubrum, (Also Candida)
Tinea capitis
Tinea corporis
Tinea imbricataEtiology: Trichophyton concentricum
Tinea cruris
Tinea cruris
Tinea unguium - onychomycosis
Tinea barbae
Tinea manum
Dermatology Image Atlas: Dermatology Images - dermatlas.med.jhmi.edu
Tinea pedis
The Dermatophytes - Zoophilic
The Dermatophytes - Zoophilic
Laboratory Diagnosis
• Requires demonstrating hyphae/arthroconidia from skin, hair, nails
• Direct preparation:• Lesion scrapings/hair examined by calcofluor/KOH
• Alternatively - Wood’s Light: • UV irradiation of infected hair, false positive/negative
• Report: Hyphal fragments/arthrocondida seen
• Culture: SDA +; SDA-CC + LPCB
Direct KOH prep: Hyphal fragments seen
http://www.mycology.adelaide.edu.au/virtual/2009/ID2-Oct09.html
The Dermatophytes: Morphology
Epidermophyton spp. - Smooth walled macroconidia borne in clusters of 2 or 3; no microconidia
Trichophyton spp. - Rare, smooth, thin-walled macroconidia; numerous spherical or teardrop shaped microconidia
Microsporum spp. - Numerous, large, thick, rough-walled macroconidia; rare microconidia
Treatment of the dermatophytoses• Localized cutaneous - topical agents
– Clotrimazole (Lotrimim), Miconazole (micatin)– Tolnaftate (tinactin), terbinafine (lamisil)
• Hair, nails – oral therapy– Fluconazole, itraconazole, griseofulvin
• Griseofulvin – Concentrates in newly keratinized layers of cells– Virtually eradicated epidemic tinea capitis; used in tinea unguium
and extensive infections.
• Recurrences are common
Non-dermatophytic Onychomycosis:
• Candida spp.– Fluconazole
• Scopulariopsis spp.• Scytalidium spp.
– partial surgical nail removal + antifungal
• **Possible other nail pathogens:– Aspergillus spp.– Fusarium spp.– Acremonium spp. **nail pathogen vs. saprobe on abnormal nail material ** Must have: > 1 KOH positive!! > culture positive isolation of same agent!!
**R/O fungal contamination of the culture**
Case resolution…
• Wood Light – positive• Skin biopsy– Enterococcus spp. and Trichophyton tonsurans– Endothrix dermatophyte infection
• Treated with griseofulvin and Selsun• New hair growth and resolution of pustular
eruption at 2 week follow-up• Treatment continued for 8 weeks with complete
hair re-growth and no permanent alopecia
Superficial Mycoses
• Tinea versicolor – AKA pityriasis versicolor– Malessezia furfur
• Tinea nigra palmaris– Hortaea (Exophiala) werneckii
• Piedra – black– Piedraia hortai
• Piedra – white– Trichosporon beigelii
Superficial Mycoses
• Tinea versicolor – AKA pityriasis versicolor– Malessezia furfur• Very common – up to 60% infected population in
certain tropical environments• Most common in tropic and subtropics• Person-to-person transfer• Liopophilic fungus that degrades lipids to produce acids
that damage melanocytes = hypopigmented patches w/ dark skin, pink or brown w/ light skin• Little-to-no host immune reaction
Tinea (pityriasis) versicolorChest
Back
Skin Scraping – Direct Prep (KOH)
• Diagnosis made by direct exam• Does not culture routinely - lipophilic• Treatment: 2.5 % Selenium sulfide or topical cream
azoles – Severe cases: Oral ketoconazole
“collarette”
“Spaghetti and meatballs”
Superficial Mycoses• Tinea versicolor – AKA pityriasis versicolor– Malessezia furfur
• Tinea nigra–Hortaea (Exophiala) werneckii
• Piedra – black– Piedraia hortai
• Piedra – white– Trichosporon beigelii
Superficial Mycoses• Tinea versicolor – AKA pityriasis versicolor– Malessezia furfur
• Tinea nigra–Hortaea (Exophiala) werneckii– Superficial phaeohyphomycosis– Solitary, irregular, pigmented macule usually on palms
or soles– Tropic or subtropic– Traumatic inoculation– Not contagious– Can resemble a malignant melanoma
Tinea nigra – H. werneckii
http://www.mycology.adelaide.edu.au/virtual/2007/ID2-Feb07.html http://www.mycology.adelaide.edu.au/virtual/2007/ID2-Feb07.html
1. KOH prep = pigmented hyphae and yeast
2. Culture = dematiaceous, yeast-like colony in 3 weeks
3. Microscopic = two-celled, cylindrical, yeast-like cells
4. Treatment: Topical azoles
Superficial Mycoses• Tinea versicolor – AKA pityriasis versicolor– Malessezia furfur
• Tinea nigra palmaris– Hortaea (Exophiala) werneckii
• Piedra – black–Piedraia hortae
• Piedra – white– Trichosporon beigelii
Superficial Mycoses• Tinea versicolor – AKA pityriasis versicolor
– Malessezia furfur• Tinea nigra palmaris
– Hortaea (Exophiala) werneckii
• Piedra – black–Piedraia hortae• Tropical, poor hygiene, uncommon• Small, dark nodules surrounding hair shaft• Clumped together by cement-like substance with asci and
ascospores• Diagnosis = direct exam• Treatment = haircut, washing
Superficial Mycoses• Tinea versicolor – AKA pityriasis versicolor
– Malessezia furfur• Tinea nigra palmaris
– Hortaea (Exophiala) werneckii• Piedra – black
– Piedraia hortai
• Piedra – white– Trichosporon beigelii
– Tropical and subtropical, poor hygiene– Affects hairs of groin and axillae– Forms soft, white/brown swelling on hair shaft– Shaving and washing
Superficial Mycoses• Tinea versicolor – AKA pityriasis versicolor– Malessezia furfur
• Tinea nigra palmaris– Hortaea (Exophiala) werneckii
• Piedra – black– Piedraia hortai
• Piedra – white– Trichosporon beigelii
• Other non-dermatophytic (several)– E.g. Candida, Fusarium, and more…
Subcutaneous mycoses
• AKA: Inoculation Mycoses – normal soil inhabitants
• Primary infection in deep skin, muscle or connective tissue
• Slowly progressive and chronic, usually confined
• Not transmissible
• Subgroups of subcutaneous mycoses I. Sporotrichosis II. Chromoblastomycosis/PhaeohyphomycosisIII. MycetomaIV. Subcutaneous Zygomycosis
Sporotrichosis – Sporothrix schenkii
• Epidemiology : – Decaying vegetation, esp used for mulching– Enters via splinters, thorn pricks
-Occupational hazard• Clinical Aspects:
– Primary nodular lesion necrotic ulcer, suppurative– Proximal lymphatics may chronically infect (dissemination rare)
• Sporothrix schenckii: – Direct prep: RARE blastoconidia– Sporothrix is a thermal dimorph– At RT: DEMATIACEOUS colony, HYALINE septate hyphae, delicate lateral
conidiophores w/ delicate rosettes of conidia– At 37°C in vivo & in vitro: oval, cigar-shaped blastoconidia.
• Treatment:– Itraconazole
Chromoblastomycosis• Epidemiology:
– tropics – PR, Cuba, Costa Rica and Brazil– Soil saprobes; dematiaceous fungi– Trauma is required, occurs when shoes are rarely worn
• Clinical Manifestations: – Not contagious– Incubation unknown– Chronic skin and subcutaneous infections– Small raised papule, ulcerates & encrusts dry, raised lesion usually on foot/leg– Satellite lesions hyper-elevate - 10-15 yrs from onset
Chromoblastomycosis – Clinical Manifestations
Chromoblastomycosis
• Laboratory Diagnosis: – Direct Prep: Copper-colored, multiple dividing cells– Three major organisms: Cladosporium, Fonsecaea, Phialophora– Culture = differ by conidial structures– Can be considered dimorphs – yeast-like in vivo, mould in vitro
• Treatment: – Specific antifungals usually ineffective– Itraconazole, terbinafine, or posaconazole– Combined with 5-fluorocytosine in refractory cases
Phaeohyphomycosis• Epidemiology:
– Syndrome caused by more than 20 different saprobes– Fungi appear in tissue as irregular hyphae, not the sclerotic cells seen in
Chromoblastomycosis– Traumatic inoculation
• Clinical syndromes:– Solitary inflammatory cyst– Slow growing (months to years)
• Laboratory Diagnosis:– Surgical excision of cyst = inflammatory cyst with fibrous capsule, necrosis, fungal
elements• Treatment:
– Surgical excision– Itraconazole, posaconazole, voriconazole, terbinafine
Mycetoma
• Epidemiology :– tropical & subtropical– Soil saprobes– Trauma required for inoculation
• Clinical Manifestations: – Not contagious– Swollen deep seated lesion of hand or foot
Mycetoma – Clinical Manifestation
Mycetoma
• Laboratory diagnosis: – Caused by many diverse microbes– Eumycetoma (fungal mycetoma)
• Scedosporium (teleomorph Pseudallescheria)• Resistant to Amphotericin B!
– Actinomycetoma (actinomycotic mycetoma)• Actinomyces, Nocardia, Actinomadura, Streptomyces
• Treatment: – Bacterial – antibiotics– Fungal – surgery and long-term treatment
Subcutaneous Zygomycosis• Epidemiology:
– Africa, India, Latin America– Traumatic implanation
• Conidiobolus coronatus and Basidiobolus ranarum
• Clinical Syndromes:– B. ranarum – large, movable mass localized to shoulder, pelvis, hip and
thigh– C. coronatus – confined to rhinofacial area
• Laboratory diagnosis:– Biopsy = focal clusters of inflammation, eosinophils, zygomycete hyphae
• Treatment:– Itraconazole