superficial and cutaneous mycoses

Question 1

mycoses

Answer 1

superficial mycoses: Malassezia furfur, hortaea werneckii/exophiala werneckii, piedraia hortae, trichosporon

Cutaneous mycoses: dermatophytes (Trchophyton rubrum, T. mentagrophytes)

Subcutaneuous mycoses: sporothrix schneckii

Question 2

Malassezia furfur

Answer 2

infection: Pityriasis (Tinea) versicolor
Morphology: lipophilic yeast
epidemiology:passed by humans by direct or indirect transfer of material
clinical: small pigmented macules, affected areas dont tan
Lab: direct microscope in a KOH prep of epidermal scales
Treatment: topical azoles or selenium sulfide shampoo, or oral azole if bad

Question 3

Hortaea werneckii/Exophiala Werneckii

Answer 3

Infection: Tinea nigra
Morphology:dematiaceous (dark mold)
Epidemiology: inoculation into superficial layers of epidermis
Clinic: Solitary, pigmented, irregular macule, on palms or soles, can look like malignant melanoma, infection is not contagious
Treatment: topical azole or terbinafine

Question 4

Piedraia Hortae

Answer 4

infection: black piedra
Morphology: asci/ascospores
Epidemiology: poor hygiene in hair
Clinical syndrome: Presence of hard dark nodules that surround hair shaft
Treatment: can be cured w/ haircut and antifungal agents

Question 5

Trichosporon, T. inkin, T asahii, and T. mucoides

Answer 5

Infection: white piedra, remerging as a systemic mycoses in HIV
epidemiology: poor hygiene
Clinical Syndromes: affects hair of grain and axillae, fungus surrounds the hair shaft and forms white/brown swelling of hair strand
Lab: cyclohexamide inhibits growth
Treatment: can be cured by hair cut, topical azole

Question 6

Dermatophytes/ Dermato phytoses

Answer 6

Trichophyton, Epidermophyton, and Microsporum are the dermatophytes:

The big species are Trichopyton rubrum, and Trichopyhton mentagrophytes

Infection: superficial keratinized tissue (skin, hair, nails) called tenias
Tinea capitis- scalp, lashes and brows (endo thrix in hai ecto out of hair)
Tinea pedis- foot (athletes foot)
Tinea barbae- beard
Tinea corporis- smooth or glabrous skin
tinea cruris- groin (jock itch)
tunea unguium (nails

Morphology: restricted to skin unable to grow at 37 c and serum
Ecology: zoophilig- live on animals, geophilic- live in soil. anthropophillic- live in humans
Clinical syndrome- pin point then expand out (worm like appearance)
Lab tests: direct microscope, Wood lamp (if green- fungus, if red erythrasma, caused by bacteria), dermatophyte test media, coccidiodes imitis can resemble a dermatophyte and grow on test media
Treatment: infections that dont involve the hair or nails (topical) chronic oral griseofulvin, azoles and terbinafine

Question 7

Subcutaneous Mycoses

Answer 7

Sporothrix Schenckii
infection disease: lympho cutaneous sporotrichosis, trauma introduction thru dermis, most common in US
morphology: thermally dimorphic, room temp: mold. body temp, yeast

Clinical: primary site, mild infection, then travels thru lymphatics

Lab diagnosis: need to culture at two temps,
Treatment: itraconazole, long term