Superficial, cutaneous, and subcutaneous fungal infections

The organisms which participate in cutaneous mycoses infections are known as ______________

*Dermatophyte*

T or F: malassezia furfur is a lipophilic, opportunisitic yeast fungi that is not dimorphic.

*False*: M. furfur is lipophilic and it is opportunistic pathogen and it is dimorphic she said that the reason that M. furfur are normally located on areas that have lots of sebaceous glands is because they are lipophilic

What are the four major kinds of subcutaneous fungal infection?

1. Sporotrichosis 2. Chromoblastomycosis 3. Phaeohyphomycosis 4. Mycetoma

For each of these tinea give the location on the body 1. Tinea capitis 2. Tinea barbae 3. Tinea corporis 4. Tinea cruris 5. Tinea pedis 6. Tinea unguium (what is this also called) 7. Tinea manus 8. Tinea faciei

1. Tinea capitis of the scalp, eyebrow, and eyelashes 2. Tinea barbae of the beard 3. Tinea corporis of the smooth or glabrous skin 4. Tinea cruris of the groin 5. Tinea pedis of the food 6. Tinea unguium of the nails (also known as *onychomycosis* 7. Tinea manus of the hand 8. Tinea faciei of the face All of these tineas could also be called ringworm of the beard, scalp etc etc.

what is the world distribution of tinea nigra?

Africa, Asia, central and south america

When you do the laboratory diagnostic test of growing the fungus on specialized media, what are some general features that you are looking at to distinguish the fungi?

Characterized by a specific pattern of growth in culture and by production of macroconidia and micro condia

Sample question: A 30 year old woman has worked hard to create beautiful rose garden. She sustains a minor scratch on her forearm while working with her roses. A week later the wound develops papules that turn into nodules which have begun to ulcerate. Antibiotic therapy fails to treat the symptoms. Microscopic examination of the lesions reveals the presence of yeast cells that assume a cigar shape. which of the following is the most likely diagnosis? A. blastomycosis B. chromomycosis C. Coccidioidomycosis D. histoplasmosis E. sporotrichosis

E. sporotrichosis - I think but she didn't actually give the answer

T or F: tinea nigra infection is contagious

False: it is not contagious

Which parts of the body are more prone to subcutaneous fungal infections?

Feet, hands, arms and buttocks are more prone

______ nail infections are usually cured more quickly and effectively than ____nail infection

Finger nail is quicker than toenail

__________ __________ lesions: the fungus remains limited to the skin and does not involve the lymphatic. Other forms of sporotrichosis include primary, secondary pulmonary sporotrichosis and disseminated disease.

Fixed cutaneous lesions

Sporotrichosis: It is a ________ infection characterized by nodular lesions of the cutaneous or subcutaneous tissue and adjacent ___________ that _______, ________ and _________.

It is a chronic infection characterized by nodular lesions of the cutaneous and subcutaneous tissue and adjacent lymphatics that suppurate, ulcerate, and drain

The tineas can affect the skin on almost any are of the body. These infections are usually _________, they show what other signs and symptoms?

Itchy Redness, scaling, or fissuring of the skin, or a ring with irregular borders and a cleared central area may occur. See pictures of these lesions on different areas of the body on slide 15 Note: tinea cruis is infection of groin also known as "jock itch"

Likewise with hair and nails, being part of the skin, only the ________ layers are invaded by dermatophyte.

Keratinized

Which type of sporotrichosis is common in U.S.?

Lymphocutaneous sporotrichosis

Where geographically Is chromoblastomycosis most common?

Most common in tropical and subtropical regions

Where is the sporothrix shenkii fungus naturally found?

Naturally found in soil, hay, sphagnum moss, and rose bushes

S. Schenkii asteroid bodies represent what?

Represent the host's immune response

All the dermatophytes have in common the ability to invade the _______, ________, or ________. In each case, these fungi are keratinophilic and __________ and so are able to break down the keratin surfaces of these structures.

Skin, hair, and nails Keratinolytic

What is the etiologic agent of lymphocutaneous sporotrichosis?

Sporothrix schenckii

Which of the sporothrix species is common in the USA and what systems does this fungus affect?

Sporothrix shenkii is common in the USA and the fungus affect the skin and the lymphatic system

What are the treatments for phaeohyphomycosis?

Surgical resection of well-localized lesions Amphotericin B, oral ketoconazole and itraconazole

What is the treatment for sporotrichosis?

Treatment: potassium iodide (oral in milk) (cutaneous infection) Amphotericin B (disseminated infection)

What is the most common etiologic agent of tinea unguium? What is a simple test to detect this species?

Trichophyton rub rum most common etiologic agent Fluoresces yellow to green under wood's lamp

T or F: tinea capitis is highly contagious

True

T or F: cutaneous mycoses (tinea or ringworm) is very contagious

True - she just said this in lecture

Chromoblastomycosis infections are often seen in workers injured with _________

Woods

what are the diagnostic procedure for pityriasis versicolor?

although not usually necessary for establishing the diagnosis, culture may be performed using synthetic mycologic media supplemented with olive oil as a source of lipid. growth of yeast like colonies appear after incubation at 30 degrees celsius for 5 to 7 days. microscopically, the colonies are comprised of budding yeast like cells with occasional hyphae 1. direct microscopic examination of KOH treated skin scrapings reveals fungal elements demonstrating the presence of yeast cells in clusters and short hyphal elements classical "spaghetti and meat balls" appearance 2. Wood's lamp - lesions appear pale yellow to yellow-green 3. culture - not routinely done

what is the unique risk factor for Malassezia furfur infection (pityriasis versicolor)?

condition that reduces the rate of desquamation, that is shedding of epidermal cells, predisposing factors: poor nutrition, excessive sweating and pregnancy

Superficial mycoses are usually of __________ concern only and area easy to diagnose and treat.

cosmetic

what is the treatment for mycetoma?

difficult to treat with antimycotic drugs. Amputation is usually the final action

Tinea nigra most often affects children and young adults, with a higher incidence in which gender?

females

what are the general characteristics of Malassezia furfur? (what is its shape, what is its solubility, is it part of normal flora)

general characteristics: Malassezia furfur is a lipophilic, yeast like organism. It is a part of normal flora, found in areas of body rich in sebaceous glands

what is diagnosis of mycetoma based upon?

macrospically examination of sclerotia. Sclerotia are mounted in sterile saline and then crushed. microscopically fungal hyphae with many intercalary swollen cells can be seen.

Fungal mycetoma: __________, madura foot deforming infection on the foot of the hand may take years to develop.

maduromycosis

what is the causative agent of pityriasis versicolor?

malassezia furfur

what are the symptoms of mycetoma?

massive induration with draining sinuses

fungal mycetoma is a clinical syndrome characterized by _______, ________, and ________.

mycetoma is a clinical syndrome characterized by tumefaction, draining sinuses, and sclerotia (granules, grains)

her slide talks about a M. mycetomatis fungus and shows its KOH and culture as diagnosis for mycetoma, is this fungus dimorphic?

no, it is only hyphael form so the culture is fuzzy mold and the microscopy shows hyphal structure

what is the etiological agent of mycetoma?

petriellidium boydii is the most common eumycotic mycetoma in the United States and Europe

there is little to no host reaction in pityriasis versicolor, and the lesions are asymptomatic, with the exception of mild _________ in severe cases.

pruritis

Mycetoma the infections starts as a small ________________________________.

small indurated subcutaneous papule

what is a condition that has a similar presentation to pityriasis versicolor that you would need to differentiate it from?

the autoimmune condition vitiligo

Pityriasis versicolor has not been documented in animal. How is human infection thought to be transmitted?

thought to result from the direct or indirect transfer of infected keratinous material from one person to another

what is the method of transmission of the fungal infection to humans?

traumatic inoculation

What is the treatment for tinea nigra?

treatment: azole cream

The tissue exudates _______, ________, or ________ granules (sclerotia) (colors)

white, yellow or black granules

what are the clinical features of Pityriasis versicolor?

hyperpigmented or hypopigmented macular lesions that scale readily, giving it a chalkybranny appearance, that occur most frequently on the upper torso arms and abdomen (on the next slide she says that the shoulder, face, and neck are often involved as well but any part of the body may be affected) she then goes on to say that the lesions are irregular, well-demarcated patches of discoloration that may be raised and covered by a fine scale.

what are rare complications of the pityriasis versicolor disease?

infection of the hair follicles, resulting in folliculitis, perifolliculitis, and dermal abscesses, is a rare complication of this disease

M. furfur is also associated with what other dermatopathologic condition other than pityriasis versicolor?

seborrheic dermatitis and dandruff

Pityriasis versicolor is an asymptomatic colonization of the _____ _______.

stratum corneum

Tinea nigra is a superficial fungal infection of the _____ ______ (which skin layer?)

stratum corneum

Superficial fungal infections (mycoses) occur in which parts of the skin?

superficial fungal infections occur in outermost layers of skin and hair her notes say that superficial mycoses are fungi that colonize the keratinized outer layers of the skin, hair, and nails

what is the presentation of tinea nigra?

tinea nigra apperas as a solitary, irregular, pigmented (brown to black - her slides say gray to black) macule, usually on the palms or soles. It is asymptomatic, well demarcated macular lesions. nonscaly macules with well-defined borders (I think this fungus also interferes with melanin production; note, she gave the name of the fungus on the slide but didn't seem concerned with us knowing it)

what is the treatment for pityriasis versicolor?

treatment - preparation containing selenium disulfide, hyposulfite, thiosulfate, or salicylic acid, ketoconazole (1% in cream)

Pityriasis versicolor is a disease of healthy persons that occurs worldwide, but it is most prevalent in ________ and _________ regions.

tropical and subtropical regions

T or F: superficial mycoses do not elicit a host immune response

true; infections caused by these organisms elicit little or no host immune response and are nondestructive and thus asymptomatic

which age group is most commonly affected by pityriasis versicolor?

young adults

Phaeohyphomycosis are subcutaneous fungal infections characterized by the presence of what type of fungal elements?

"Phaeo" is the Greek word denoting "dark". They are a heterogenous group of infections characterized by presence of darkly-pigmented fungal elements.

What are the diagnostic tests for cutaneous mycoses?

1. KOH of hair or scalp scrapings 2. Growth on specialized media 3. Wood's lamp

What are the treatments for cutaneous mycoses (tineas)? And their mechanisms of action

1. Local - (topical), miconazole, clotrimazole and econazole. All of the azole derivatives appear to work by interfering with the cytochrome P-450-dependent enzyme systems in sterol synthesis and therefore increases membrane permeability and inhibits steroids synthesis 2. Systemic: griseofulvin, inhibits the initiation of infection but not established infection. It appears to work by affecting the microtubular system of fungi (note: there are other systemic agents listed in later notes - itraconazole, fluconazole, terbinafine)

Sporotrichosis can be separated into what five types of infection? What determines which type of infection develops?

1. Lymphocutaneous 2. Fixed cutaneous 3. Mucocutaneous 4. Disseminated 5. Pulmonary The portal of entry of the fungus, the dose, and the effectiveness of the host's response determine which type of infection develops

The clinical signs and symptoms of dermatophytosis vary according to the etiologic agents, the host reaction, and the site of infection. As well as the keratin they prefer. Give the keratin preferred by each of the different genera (and give the shape of their spores)

1. Microsporum - keratin of skin and hair (fusiform or spindle shape condia) 2. Epidermophyton - keratin of skin and nails (snow shoe or beaver's tail macroconidia with thin smooth walls) 3. Trichophyton - keratin of hair, skin, and nail (pencil or cigar shaped microconidia more in number than macroconidia) (She didn't seem too concerned with us knowing the sporulation patterns)

What are the two ways to categorize dermatophytes?

1. Morphological - depending on the sporulation patterns (microsporum, trichophyton, epidermophyton) *2. Clinical - depending on the location of the lesion* (remember that the lesion is referred to as ringworm or tinea) She said in class that we don't really need to focus on the genera or species, they typically don't culture these fungi but diagnose based on the annular appearance of the lesion but cultures of the different genera are on slide 11

What are the common features of subcutaneous mycoses infections?

1. They are associated with some form of trauma occurring at the site of infection before the lesions developed 2. The infections occur on parts of the body that are most prone to be traumatized (e.g. feet, legs, hands, arms, buttocks) 3. The etiological agents are usually organisms commonly found in the soil or on decaying vegetation 4. They all produce granuloma

what are the four types of superficial mycoses?

1. Two involve the skin A. pityriasis versicolor B. Tinea nigra 2. Two involve the hair A. black piedra B. white piedra she is focusing on the ones involving the skin

what is the diagnostic procedure for tinea nigra?

10 to 20% KOH-treated scraping: yeast like cells with hyphal fragments *do this to rule out the diagnosis for malignant melanoma and Nevi*

Clinically the tineas are classified according to the ________ site or __________ affected

Anatomical site or structure affected

How are dermatophyte infections spread? __________ - associated with humans ________ - associated with animals ___________ - found in the soil (Same types as before, for this slide she said the type home message was that they were very very contagious)

Anthropophilic - associated with humans Zoophilic - associated with animals Geophilic - found in the soil

what is the difference in presentation of pityriasis versicolor lesions between dark and light-skinned individuals?

Because M. furfur tends to interfere with melanin production, lesions are hypopigmented in dark-skinned individuals. In light-skinned individuals, the lesions are pink to pale brown and become more obvious when they fail to tan after exposure to the sunlight.

Phaeohyphomycosis infection include ________ or _________ infections (where the infections can occur). These fungi can also cause ___________, ______________, ____________, and _________________

Cerebral or subcutaneous These fungi can also cause chronic paranasal sinusitis, prosthetic valve endocarditis, keratomycosis and widely disseminated infections On her slide she has this listed "types of infections: abscesses; localized, cerebral, subcutaneous, paranasal sinusitis, prosthetic valve endocarditis"

What are the clinical features of chromoblastomycosis?

Characterized by the development of papules at the site of inoculation which over the years becomes verrucous (warty) crusted. At the progression of the lesion: appears to vegetate, "cauliflower like" appearance. It is characterized by the development of verrucous (warty) nodules at the site of inoculation. (Remember it is a chronic infection of the skin) Her PowerPoint says colored lesions that start out scaly and become raised, cauliflower-like lesions

What are the laboratory diagnostic procedures and results to confirm sporothrix shenki infection?

Culture, skin tissue specimen preserved in 10% KOH demonstrate the "cigar-shaped" budding yeast form of S. Schenckii. Asteroid bodies may be present, star shaped, with rays of eosinophilic material radiating from central yeast like cell or cells. The yeast like cell is basophilic, 3 to 5 micrometers in diameter. The entire complex may be 10 to 15 micrometers in diapers Her slide says rosette pattern of condia at 25 degrees celsius on Sabouraud's agar (The yeast form is in the body the hyphal form with conidia is outside the body)

What are cutaneous mycoses? (What do they affect?)

Cutaneous mycoses: infections that extend deeper into the epidermis, as well as invasive hair and nail disease

Immunity: Allergic reaction to the fungus of a cutaneous mycoses leads to lesions at different sites from the infection. These lesions are called __________ or ______. What type of hypersensitivity reaction is this?

Dermatophytids or ids Delayed type hypersensitivity

What are the diagnostic features of chromoblastomycosis?

Direct examination: Presence of pigmented fungi in tissue sections or pus. The thick-walled cells are called sclerotic bodies or medlar bodies*** - these are copper-colored spherical yeast called Medlar bodies in tissue (Looks like copper penny this is on a histology of the tissue)

What are the causative agents of Phaeohyphomycosis? (Generally speaking, and what are their shared characteristics)

Her slide simply says dematiaceous molds The etiologic agents of phaeohyphomycosis are numerous and varied in their generic classification. Majority of them belong to the dematiaceous hyphomycetes and they all produce melanin in the cell wall (subcutaneous infection with dark-walled hyphae)

Subcutaneous mycoses include a wide spectrum of fungal infections, which are introduced at the site of infection by what means?

Implanted at the site of trauma (E.g. splinter, rose bush thorn, or insect bite) all subcutaneous fungi have this common feature because they are not invasive so they have to be inoculated

In the case of skin infections, which layer(s) of the epidermis do the dermatophytes invade?

In the case of skin infections, the dermatophytes invade only the upper, outermost layer of the epidermis, the stratum corneum. Penetration below the granular layer of the epidermis is rare

Subcutaneous fungal infections involved what structures?

Infection involved deeper layers of dermis, subcutaneous tissue or bone

What are the signs of an onychomycosis? (She has these sets of notes under the slide showing toe nail infections with Candida albicans but don't know if it is specific to these)

Irregular border between the pink portion of the nail and the white outside edge of the nail when the nail has lifted from the nail bed. Larger portion of the nail is opaque, can be whitened or discolored to yellow or green. Discoloration underneath the nail may occur as a result of secondary infection

What are the clinical features of lymphocutaneous sporotrichosis?

It is characterized by nodular and ulcerative lesions that develop along lymphatics that drain the primary site of inoculation. Despite involvement of the lymph channel, it is localized without fever or malaise and without involvement of the regional lymph nodes - those in the axilla or groin

Lymphocutaneous sporotrichosis usually affects what population of people?

It usually affects farmers, horticulturists, rose gardners, plant nursery workers (This is rose gardener's disease)

Generally cutaneous mycoses affect _______ layers of the integumentary and its appendages. They can use _________ as a nitrogen source.

Keratinized Keratin

what is the etiologic agent of pityriasis versicolor?

Malassezia furfur (pityrosporum orbiculare)

Sporotrichosis is a chronic infection that ordinarily begins as a subcutaneous _________ at the site of injury and progresses to ___________ channels

Nodules Lymphatic channels *her slide had the word chronic emphasized*

For some reason I had delayed type hypersensitivity reaction written on the cutaneous mycoses slide n

Not sure why

Tinea unguium infection would have to be differentiated from an infection of the nail caused by which fungus? How would you differentiate these in the lab?

Onychomycosis can be caused by Candida albicans as well The Candida albicans would show germ tube formation, while the etiologic agent of tinea unguium (nail) would show hyphae with spores

What laboratory tests would you use to diagnos phaeohyphomycosis?

Periodic acid-Schindler (PAS) or methenamine silver stain: dark-walled hyphae

Which age range does tinea capitis more commonly affect?

Prepubescent children

The clinical manifestation fo these cutaneous mycoses are also referred to as __________ or _________

Ringworm or tinea

lymphocutaneous sporotrichosis is also known as what?

Rose Gardner's disease

All the fungi that cause subcutaneous infection in humans are found as _____________ throughout the world?

Saprobes (I think these are fungi that act as descomposers feeding on decaying organisms)

___________ is the principal agent of tinea capitis in the United States (Note: she didn't seem like she cared if we knew this genus and species info)

T tonsurans

The eosinophilic material of asteroid bodies is what?

The eosinophilic material of asteroid bodies is a complex of antigenic material from the fungus and the antibody protein from the host. (The three key features for diagnosis of sporothrix shenkii are cigar-shaped yeast, rosette, and asteroid bodies)

What are the signs of a tinea capitis infection?

Tinea capitis: scalp, hair, eyebrows Hair becomes grayish, dull and brittle due to ectothrix invasion of hair, hair breaks off near the base of the shaft

What is a common means of transmission that can result in tinea manum?

Tinea manum is ringworm of the hand Contact with another site of infection particularly the feet or groin Direct contact with an infected animal or soil

The various forms of dermatophytosis are referred to as _________ or __________.

Tineas or ringworm

What is the treatment for chromoblastomycosis?

Treatment: 1. Surgical excision in the early stages 2. 5-flucytosine (oral)

Laboratory diagnosis: A wood's lamp is a light that uses long wave _________ light. When an area of the scalp that is infected with tinea (a type of ringworm fungus) is viewed under a Wood's light, the fungus may ________. This test may be done to detect the presence of a _______ scalp or skin infection

Ultraviolet light Glow Fungal

what should be on your differential diagnosis along with tinea nigra?

because the lesion grossly may resemble a malignant melanoma, biopsy or local excisions may be considered. such invasive procedure may be avoided by a simple microscopic examination of skin scrapings of the affected area also could look similar to a nevus

Oral antifungal agents with systemic activity against dermatophytes include ___________, ________, _________, and ___________.

Griseofulvin, itraconazole, fluconazole, and terbinafine

What are some other types of infection that would need to be on your differential diagnosis for a case of sporotrichosis?

1. Atypical mycobacterial infection, especially M. Marinum 2. Nocardia infections, particularly N brasiliensis 3. Leishmania brasiliensis infection 4. Tularemia Because these have a similar presentation

What is the etiological agent of chromoblastomycosis? (What is the most common agent?)

Etiologic agent - is caused by dematiaceous (pigmented) fungi (phialophora and cladosporium). The most common agent is Fonsecaea pedrosi

Immunity: T or F: you get a classical humor but not a cell mediate protective immunity to cutaneous mycoses

False: no classical humoral or cell mediate protective immunity

T or F: sporothrix shenkii is monomorphic

False: sporothrix shenkii is a dimorphic fungi (converts at 35 degrees celsius from mold to yeast)

T or F: if you get a tinea or ringworm infection once you can't get it again

False: you don't build up an immunity to these so you can get ringworm over again after you have already been exposed once

Her slide shows three types of fungal hair infection of the cutaneous mycoses category but she didn't mention it ________ hair infection - inside hair and at the root of the hair shaft The other two types are ________ and _________.

Favic hair infection Ectohrix Endothrix

The term dermatophytosis refers to a complex of disease caused by any of several species of taxinomically related _________ fungi in the genera _________, _________ and __________. These fungi are known collectively as the __________, and all possess the ability to cause disease in humans and/or animals. (The first blank is the morphology)

Filamentous fungi Genera: trichophyton, epidermophyton, and microsporum (they vary based upon sporulation pattern) Dermatophytes

Different species of dermatophyte varies markedly from one ecological niche to another. 1. ___________ - soil 2. __________ - lower animals and bird 3. ____________ - humans only

Geophilic - soil Zoophilic - lower animals and bird Anthropophilic - humans only

All of the subcutaneous fungal infections produce ____________

Granuloma