Fungi - Cutaneous Mycoses

Question 1

Malessezia furfur (Pityriasis versicolor)

lab tests

Answer 1

Malassezia’s Italian Restaurant

Spaghetti and Meatball appearance on KOH prep of skin scrapings.

Stratum corneum (top layer of skin) is the layer that is damaged.

Question 2

Malessezia furfur (Pityriasis versicolor)

source

Answer 2

Malassezia’s Italian Restaurant

• Hot and humid conditions!

The fungus will convert to the disease form with humidity.

• Neonates can get furfur from TPN (total parental infusions), since the fungus will grow in catheters of lipid transfusions.

Question 3

Malessezia furfur (Pityriasis versicolor)

signs and symptoms

Answer 3

Malassezia’s Italian Restaurant

• Patches of hypo AND hyper pigmentation on chest and back.

(Lipid degradation → builds up acid → damages melanocytes → loss of pigmentation)

• In neonates (NICU) with TPN (total parental infusion) furfur can grow in the catheter of lipid transfusions, causing sepsis and thrombocytopena

Question 4

Malessezia furfur (Pityriasis versicolor)

Treatment

Answer 4

Malassezia’s Italian Restaurant

Selenium sulfate (selsum blue) topical

Question 5

Sporothrix schneckii

lab tests

Answer 5

Shanked by a rose

Dimorphic fungus

Branching hyphae of sporothrix at 25°

Cigar shaped yeast under microscope.

Biopsy will yield cigar shape budding yeasts, multinucleated giant cells, and granules of histocytes.

Question 6

Sporothrix schneckii

source

Answer 6

Shanked by a rose

“Rose buds (or Rose gardeners) disease”

Commonly found on rose thorns, tree bark, bushes, and plants.

Usually introduced into the skin by a local trauma (stuck by thorn!).

Question 7

Sporothrix schneckii

signs and symptoms

Answer 7

Shanked by a rose

Usually introduced into the skin by a local trauma (stuck by thorn!) that leads to a pustule, ulcer, or nodule.

It then develops an ascending pattern along the lymphatics → causing red bumps along the skin (Sporotrichosis)

Question 8

Sporothrix schneckii

Treatment

Answer 8

Shanked by a rose

For lymphocutaneous sporotrichosis: itraconazole

Older tx: Potassium solution of potassium iodide

Question 9

Dermatophytes T, E, M

(Trichophyton, Epidermophyton, Microsporum)

lab tests

Answer 9

Tinea Tin Man (cause Tinea disease)

Hyphae seen on KOH prep of skin scrapings

Can diagnose microsporum strain (not others!) with Woods lamp (the microsporum will illuminate)

Question 10

Dermatophytes T, E, M

(Trichophyton, Epidermophyton, Microsporum)

source

Answer 10

Tinea Tin Man (cause Tinea disease)

Dermatophytes live on skin.

Athletes are most at risk (swimming / wrestlers)

Animals are also a source of infection.

Question 11

Dermatophytes T, E, M

(Trichophyton, Epidermophyton, Microsporum)

signs and symptoms

Answer 11

Tinea Tin Man (cause Tinea disease)

Ringworm!

Itchy.

Question 12

Dermatophytes T, E, M

(Trichophyton, Epidermophyton, Microsporum)

Name of infection by location / region

Answer 12

Tinea Tin Man (cause Tinea disease)

• Head = Tinea capitus
• Body = Tinea corpus
• Groin = Tinea cruris (crura connects base of penis to ischeal pubic rami)
• Foot = Tinea pedis
• Nails = Onchomycosis

Question 13

Dermatophytes T, E, M

(Trichophyton, Epidermophyton, Microsporum)

Treatment

Answer 13

Tinea Tin Man (cause Tinea disease)

For general inf: -azoles

Terbanifine

For more serious inf: Griseofulvin (GI side effects!)