Skin lesions: at site of inoculation

Question 1

Anthrax

Skin lesions

Answer 1

• Not very painful; prominent edema and black eschar at base.
• Regional adenopathy .
• Not systemically ill, occurring soon after exposure to animals and/or their hides (1-12 days) or bioterror.

Question 2

Diphtheria (C. ulcerans, C.
diphtheriae)

Skin lesions

Answer 2

Ulcer is indolent, gray;
Patient is impoverished, nontoxic.
Diagnose by culture.

Question 3

Mycobacterium marinum

Skin lesions

Answer 3

Exposure of hands/arms within 2-3 weeks to fish tanks; brackish water.
Not painful.
Notify lab to incubate at low temperature, ie 32 C.

With water exposure consider: Aeromonas species, Edwardsiella tarda, Erysipelothrix rhusiopathiae, Vibrio vulnificus, and Mycobacterium marinum

Question 4

M. fortuitum,
M. chelonae,
M. abscessus

Skin lesions

Answer 4

• Trauma with or without exposure to water e.g., pedicures.

- M. fortuitum is MoCo in ImmCo patients than M.chelonae or M. abscessus

Question 5

Nocardiosis (N. brasiliensis)

Skin lesions

Answer 5

Soil; spreads via lymphatics

Question 6

Plague

Skin lesions

Answer 6

Vector: Rat flea

Primary inoculation site often inapparent but may be papule, nodule or ulcer.

Fever + Suppurative lymph nodes are exquisitely tender

Question 7

Rickettsia eschar

Skin lesions

Answer 7

Tache noire marks site of tick bite,

Diffuse rash and fever.

The following have NO eschar: Rocky Mountain Spotted Fever (R. rickettsiae) or murine typhus (R.
typhi) or scrub typhus (O. tsutsugamuchi).

Question 8

Spider bites

Skin lesions

Answer 8

Brown recluse. Ulcer is very painful.

Question 9

Sporotrichosis

Skin lesions

Answer 9

Exposure: thorny plants, insects, or animals.

Not systemically ill and only mildly painful.
Spread via lymphatics.

Also consider tularemia (fever) and nocardia or perhaps M. marinum and Leishmania in differential, and look for exposure clue.

Question 10

Staphylococcal

Skin lesions

Answer 10

Painful “boils:” furuncle, carbuncle.

Question 11

Tularemia

Skin lesions

Answer 11

Exposure: Infected animals.

Fever, suppurative draining lymph nodes.

Question 12

Erysipelothrix

Skin lesions

Answer 12

Painful nodule at inoculation site, brackish water, fisherman or seafood packer with short incubation (2-7 days);

Gram positive rod;

occasionally spreads via lymphatics with systemic toxicity.