Nodular/Draining dermatoses

Question 1

What are the 3 major differentials for nodules?

Answer 1

1. Infectious
   - bacterial
   Staph furunculosis or botryomycosis
   Mycobacteria
   Nocardia/Actinomyces
   Acral lick dermatitis causing deep pyoderma

• FUNGAL
  Kerion: Microsporum canis/gypseum
  Trichophyton mentagrophytes

Eumycotic mycetoma= draining tracts with growths and grains of the fungus present. 
Curvularia geniculata (black grains) - SKIN
Pseudoallescheria boydii, Acremonium (white grains) ABDOMEN, DEADLY

Phaeohyphomycosis - pigmented fungi (melanin)

Zygomycosis - live in decaying wood and vegetable matter. RARE

Pythosis - aquatic organism not really a fungus (Pythium insidiosum) gets in DAMAGED TISSUE. pyogranulomatous inflammation. silver stain.
Lagenidiosis - pyogranulomatous inflammation + eosinophils. causes 2 dermatoses; one deadly, one stays local

Blastomycosis

Histoplasmosis

cryptococcus - pigeon poo!

coccidiomycosis

sporotrichosis

• parasitic (demodex)
• viral (papilloma virus)

2. Neoplastic
   Histiocytoma (benign cutaneous tumor of langerhans cell)

Cutaneous Histiocytosis - erythematous plaques or nodules in dermis or panniculus face back neck trunk.

Mast cell tumor

cutaneous lymphoma

melanocytoma

trichoblastoma (basal cell tumor)

3. Sterile
   - FB reaction
   - insect hypersensitivity
   - Juvenile cellulitis
   - Sterile nodular panniculitis: pyogranulomatous inflammation
   - sterile granuloma/pyogranuloma syndrome
   - follicular cyst/epidermal inclusion cyst
   - sebaceous gland nodules

Question 2

What do you first suspect when cytology of a nodule shows pyogranulomatous inflammation?

Answer 2

INFECTIOUS UNTIL PROVEN OTHERWISE

• Eumycotic mycetoma (Curvularia, Pseudoallescheria, Acremonium)
• Phaeohyphomycosis
• Lagenidiosis (Lagenidium)
• Histoplasmosis
• Sporotrichosis
• Sterile nodular pannilculitis

Question 3

Diagnostic workup of skin nodule?

Answer 3

• FNA & scrape: cytology. look for inflammatory, neoplastic, abnormal cells.
• Biopsy: culture and histopath
• culture & sensitivity: bacterial and fungal
• CBC/Chem/UA for underlying disease

Question 4

Diagnosis of a sterile skin nodule?

Answer 4

diagnosis of exclusion: rule out infection, neoplastic causes

Question 5

Pythosis/Lagenidiosis treatment

Answer 5

Treatment difficult, wide surgical excisions. Itraconazole.

Question 6

Sporotrichosis typical complaint?

Answer 6

non-healing wounds

Question 7

Blastomycosis lesions are typical at ___ junctions

Answer 7

mucocutaneous

Question 8

papilloma virus typically causes warts around ___ mucose in ____dogs.

Answer 8

oral; young

Question 9

What physical findings regarding a nodule cause you to worry?

Answer 9

poor/inflitrative margins, deep nodule, animal has systemic illness, manipulation alters the lesion, location (inoperable? eye? brain/cns? face? genitals?)

Question 10

What are the two rules of Acral Lick dermatitis?!

Answer 10

they are always infected, and always secondary to something!