Ch. 17 - Bacterial, spirochete, and protozoan infections

Question 1

Impetigo

(cause?)

Answer 1

Neutrophilic crust. Chains or clusters of cocci.

Question 2

What conditions present with neutrophils in the stratum corneum?

Answer 2

PTICSS:

Psoriasis

Tinea

Impetigo

Candida

Seborrheic dermatitis

Syphilis

Question 3

Bullous impetigo

Answer 3

Subcorneal bulla with acantholysis in granular layer.

Question 4

Suppurative folliculitis

(cause?)

Answer 4

Supurative inflammation in or around a follicle. Crust in stratum corneum.

(could be bacterial, fungal, chemical…)

Question 5

Botryomycosis

Answer 5

Large staphylococcal grains in tissue (resembles mycetoma) with abscesses and sinus tracts.

Question 6

Pitted keratolysis

Answer 6

Dell or pit in stratum corneum with rods/cocci. Located in acral skin.

Question 7

Erythrasma

Answer 7

Rods forming vertical filaments in startum corneum. Variable inflammation.

Question 8

Ecthyma gangrenosum

(cause?)

Answer 8

Necrosis of deep dermal vessels surrounded by amphophilic bacilli. No inflammatory infiltrate!

(pseudomonas sepsis)

Question 9

Rhinoscleroma

(cause?)

Answer 9

Sheets of plasma cells and russell bodies. Mikulicz cells (resembles globi of leprosy).

(Klebsiella rhinoscleromatis)

Question 10

Chancroid

Answer 10

Ulcer with necrosis/fibrin at surface. Granulation tissue with plasma cells below.

Question 11

Granuloma inguinale

Answer 11

Pseudoepitheliomatous hyperplasia with neutrophilic abscesses. Donovan bodies (organisms within histiocytes).

Question 12

Lepromatous leprosy

Answer 12

Perivascular lymphohistiocytic infiltrate with ample amphophilic cytoplasm. May form sheets with Grenz zone. Globi (amphophilic collections of mycobacteria).

Question 13

Tuberculoid leprosy

Answer 13

Epithelioid granulomas“running east-west”. Rare organisms.

Question 14

Histoid leprosy

Answer 14

Fibrous nodules and globi. Usually the result of long-acting dapsone.

Question 15

Recite three types of leprosy reactions.

Answer 15

1 (reversal/downgrading): Increased immune infiltrate.

2 (erythema nodosum leprosum): Leukocytoclastic vasculitis and onion-skin fibrosis with globi.

3 (Lucio’s phenomenon): Massive load of organisms, inflammation, and thrombosis in arterioles.

Question 16

Tuberculosis

Answer 16

Early suppurative reaction becoming granulomatous with central caseous necrosis.

Question 17

Syphilitic chancre

Answer 17

Typical-appearing ulcer (zone of necrosis, underlying granulation tissue & plasma cells). Spirochetes on silver/IF.

Question 18

Secondary syphliis

Answer 18

Vacuolar interface dermatitis with slender psoriasiform acanthosis. Endothelial swelling obliterates vessel lumen. Perivascular lymphocytes and histiocytes.

Question 19

Tertiary syphilis

Answer 19

Granulomas usually without visible organisms.

Question 20

Erythema migrans

Answer 20

Highly variable perivascular infiltrate (may contain plasma cells and/or eosinophils). Spirochetes in silver-stained sections.

(very non-specific…)

Question 21

Acrodermatitis chronica atrophicans

Answer 21

Dermal atrophy with sparse lymphohistiocytic band throughout dermis.

Question 22

Leishmaniasis

Answer 22

Granulomatous dermatitis with intracellular organisms at periphery of vacuoles.

Question 23

Acanthamoeba

Answer 23

Necrosis of deep vessels with organisms in vessel wall. Initially looks like large histiocytes.

Question 24

Answer 24

Impetigo

Question 25

Answer 25

Bullous impetigo

Question 26

Answer 26

Botryomycosis

Question 27

Answer 27

Pitted keratolysis

Question 28

Answer 28

Erythrasma

Question 29

Answer 29

Ecthyma gangrenosum

Question 30

Answer 30

Rhinoscleroma

Question 31

Answer 31

Granuloma inguinale (donovan body)

Question 32

Answer 32

Lepromatous leprosy

Question 33

Answer 33

Tuberculoid leprosy

Question 34

Answer 34

Histoid leprosy

Question 35

Answer 35

Reversal reaction (leprosy)

Question 36

Answer 36

Erythema nodosum leprosum

Question 37

Answer 37

Lucio’s phenomenon (leprosy)

Question 38

Answer 38

Tuberculosis

Question 39

Answer 39

Syphilitic chancre

Question 40

Answer 40

Secondary syphilis

Question 41

Answer 41

Tertiary syphilis

Question 42

Answer 42

Acrodermatitis chronica atrophicans

Question 43

Answer 43

Leishmaniasis

Question 44

Answer 44

Acanthamoebiasis