skin 8: fungi

Question 1

Malassezia furfur causes ??

Answer 1

Pityriasis versicolor (aka tinea versicolor aka Pityrosporum obiculare)
A chronic, mild, generally asymptomatic infection of the *stratum corneum* (cornified layers of the epidermis).

Question 2

Malassezia furfur: NF?

Answer 2

ubiquitous saprophyte is considered normal flora when present in the yeast phase alone.
It is lipophilic and lipid dependent. *ubiquitous
It is not known what causes the transition to the hyphal phase: responsible for disease

Question 3

Malassezia furfur: is it common?? where does it occur? seasonality?

Answer 3

Very common. Tropical areas can have a prevalence as high as 40% and the frequency is higher during summer months in temperate climates. (when wearing less clothes, skin looks like not tanning evenly)

Question 4

Malassezia furfur: transmission/reservoir

Answer 4

only found on humans. It can be part of the normal flora.

Question 5

Malassezia furfur: age?

Answer 5

Young adults are most frequently affected.

There is no sex or race predilection.

Question 6

known EXogenous risk factors for Malassezia furfur

ENdogenous risk factors??

Answer 6

high temperatures, high relative
humidity

application of oily preparations, creams, greasy skin malnutrition; steroid usage; hyperhidrosis; abx tx; DM; immunosuppression, and slow rate of epithelial cell turnover (vitamin A deficiency?)

Question 7

Malassezia furfur clinical manifestations: Pityriasis versicolor (synonym: tinea versicolor).

Answer 7

commonly involves: upper trunk, scalp, face and flexural areas
lesions are reddish-brown or, more often, *hypopigmented, sometimes with a very fine scale.
-substance produced by the organism that inhibits melanosome production and transfer of melanin. (ddx vitiligo)

In *hyperpigmented areas, production of larger, unpackaged and heavily melanized melanosomes has been demonstrated.
Erythema is absent and there is no pruritus.

Question 8

additional manifestations of Malassezia furfur:

Answer 8

Pityrosporum folliculitis
Seborrheic dermatitis
Dandruff (especially pruritic dandruff. Itchy flakey scalp)
Atopic dermatitis
Septicemia/pneumonia

Question 9

M. furfur

Pityrosporum folliculitis

Answer 9

(Often associated with pityriasis versicolor in the
same patient)
The organism initiates a hyperkeratosis that plugs the follicle and leads to rupture and produces granulomatous inflammation.
The result is minute, perifollicular papules and pustules, usually on the upper trunk and upper arms. These may resemble acne

Question 10

M. furfur

Seborrheic dermatitis

Answer 10

red scaly lesions predominantly located on the scalp, face and upper trunk. Some individuals are immune hyper-responders and even the normal number of Malassezia will start an inflammatory reaction.

Question 11

M. furfur

Atopic dermatitis

Answer 11

Atopic dermatitis (AD) is a chronic pruritic dermatitis that has unknown etiology. There is a growing association between M. furfur and other Malassezia sp. and induction of atopic dermatitis in adults
seems to be related to induction beta-defensins in the skin.

(dandruff)
use shampoo that contains selenium sulfide or ASA

Question 12

M. furfur Septicemia/pneumonia

Answer 12

Increasingly recognized cause of septicemia and death in stem cell transplant patients.

Question 13

M. furfur Seborrheic dermatitis tx

Answer 13

Antifungals vs. steroids are now recommended as primary treatment. Data suggest that once-daily ketoconazole gel 2% is an effective treatment for seborrheic dermatitis and a viable alternative to the ketoconazole cream 2% formulation.

Toll-like receptor 2 modifiers (decreases the topical IL-8 expression) are also showing promise in decreasing the M. furfur- associated seborrheic dermatitis relapse rate
(if think acne and try abx–>ineffective)
(if tx with corticosteroids: may go away then come back)

Question 14

M. furfur dx

Answer 14

Topical lesions exhibit pale fluoresce with Wood’s lamp.
KOH preparation of skin scrapings reveal clusters of yeast and irregular hyphae (spaghetti and meatball appearance in cases acquired in N. America).

Question 15

M. furfur px and tx

Answer 15

For pityriasis a 1-2.5% selenium sulfide ointment or shampoo, topical keratinolytic agents or polyene glycol is used.
For seborrheic dermatitis and dandruff, ciclopirox plus salicylic acid group is recommended.
Relapses are frequent. (never completely cured, but controlled)
For hyperpigmentation topical cycloserine has been shown to be very effective.

Question 16

Tinea nigra synonyms

Answer 16

(Keratomycosis nigra)
Hortaea (Exophiala) werneckii
Tinea Nigra Palmaris, Keratomycosis Nigricans Palmaris, Pityriasis Nigra

Question 17

Tinea nigra etiologic agent

Answer 17

Hortaea (formally Exophiala) werneckii.

Question 18

Tinea nigra found where geographically??

Answer 18

Central and S. America, Cuba, Puerto Rico, S.E. Asia, Indonesia, Florida and other coastal states of S.E. U.S.A.

Question 19

T. nigra acquired how?

incubation period?

Answer 19

Direct inoculation onto the skin from contact with decaying vegetation, wood or soil
Incubation periods may be as long as 20 years In the U.S.

Question 20

T. nigra age/gender/seasonality

Answer 20

95% of infections occur under the age of 18 yr. and 75% of those affected are female (in the US, ww varies)
-typically present w. cosmetic problem they want taken care of
no seasonality

Question 21

T. nigra risk factors

Answer 21

Contact with plant material and through auto-inoculation. Predisposing
factors are not understood.

Question 22

T. nigra s/s

Answer 22

A discrete, 1-8 cm dark, brown-to-black, mottled, macule forms most often on the palm or palmar surface of the fingers, although the soles may also be involved. There is no inflammation, induration or scaling.
Lesions are asymptomatic.

Question 23

T. nigra dx

Answer 23

KOH prep of skin scraping

Question 24

Tinea nigra must be differentiated from ??

Answer 24

malignant melanoma and

junctional nevus.

Question 25

T. nigra tx

Answer 25

topical agents

Question 26

Black and White Piedra agents

Answer 26

black: Piedra hortai
white: Trichosporon beigelii

Question 27

Black and White Piedra are ectothrix infections which can involve ??

Answer 27

any hair on the body, but are most often seen on the face, head, and genital areas. T

Question 28

ectothrix??

Answer 28

a sheath of arthrospores is produced on the external surface only of the hair shaft
(spore on outside of hair shaft)
makes hair look “ratty”

Question 29

Black and White Piedra found where ??

Answer 29

worldwide.

White piedra is emerging as a commonly seen hair and scalp infection in the northeastern United States.

Question 30

Neither black nor white piedra involve the ??

symptoms??

Answer 30

follicular portion of the hair or the epidermis

usually no symptoms

Question 31

White piedra looks like a white nodule (little white flecks) on the hair shaft and must be distinguished from ??

Answer 31

nits and lice.

Question 32

Black piedra forms a brown/black collar around the hair shaft. Resembles the ectothrix caused by ?? but is not ??

Answer 32

Microsporum

fluorescent.

Question 33

Black and White Piedra tx

Answer 33

Cut or shave off the affected hair is still the best treatment

recent studies indicate that scalp and hair infection may be successfully treated with a combination of oral azole antifungals and shampoos without shaving the scalp.