Derm3- Nodular Diseases

zoonotic!

cutaneous, cutaneoulymphatic, disseminated (rare in dogs, common in cats)

head, ditsal limb, tailbase

multiple non-painful nodules that ulcerate and drain purulent exudate

soil saprophyte, infection occurs from inoculation of organism into SQ tissues by rose thorns or cat fights (ie. outdoor animals and intact cats are more prone)

• cytology- easy to see in cats, fewer organisms in dogs
• culture
• histopathology
• PCR analysis
• immunofluorescent testing
• antigen testing

Itraconazole, +/- Amphotericin B

cutaneous and systemic canine cutaneous reactive histiocytosis, localized and disseminated histiocytic sarcoma complex

unknown; assumed to be immune-mediated b/c have not isolated infectious agents and they respond to immunosuppressive therapy

3-9 years old, predisposed Collies and Shetland Sheepdogs

multiple hairless, erythematous dermal to SQ nodules, non-pruritic, non-painful, lesions wax and wane, slowly progressive and may spontaneously resolve

face, neck, nasal mucosa, perineum, scrotum, feet

histopathology

sterile granuloma and pyogranuloma syndrome, multiple cutaneous histiocytomas, cutaneous lymphoma

• prednisone immunosuppression (most respond to this as sole therapy)
• azathioprine, cyclosporine, leflunomide, tetracycline/niacinamide (or doxy) as maintenance to avoid recurrence

tetracycline (or doxy or mino) and niacinamide

inflammation of the SQ fat- unknown origin

systemic lupus erythematosus, pancreatitis and pancreatic tumors, rheumatoid arthritis, lymphoplasmacytic colitis

single or multiple SQ nodules which can be of normal skin color or by erythematous or blue; initially nodules are firm but they become soft/ liquefied in center; nodules may regress or form draining tract; fever, lethargy, anorexia around the formation of new nodules

• diagnosis of exclusion: rule out bacteria/fungi/myobacterium, sterile granuloma/pyogranuloma syndrome, foreign bodies, injection site reaction, insect bite, drug reaction, neoplasia
• CBC/Chem/UA: rule out/ identify concurrent systemic diseases
• cytology: suppurative to pyogranulomatous or granulomatous with fat drops or cell present and sterile
• biopsy
• culture

• histopath: suppurative to pyogran/granulomatous with fat drops or cells
• culture: negative for fungi, bacterial, mycobacterium

• surgical excision of solitary masses may be curative
• [many lesions] immunosuppressive drugs- prednisone, monitor- if no response within, 2-8 wks add another immunosuppressive agent

if remission is achieved within first 2 weeks of prednisone therapy, decrease dose by 25% every 7 days until lowest effective dose every other day

2-8 weeks

idiopathic, have not identified infectious agents/ respond to immunosuppressive therapy- assumed immune-mediated

Leishmania, Mycobacterium

firm, hairy or alopecic erythematous papules, nodules, or plaques; may form draining tracts and ulcers on paws

head, distal extremities, +/- tongue, +/- prepuce

• rule out other causes of deep infections (bacteria, fungi, foreign bodies, cutaneous eosinophilic granulomas, cutaneous neoplasms)
• clinical appearance
• histo
• negative culture

• [single nodule] surgical excision can be curative
• [many lesions] immunosuppressive drugs- prednisone, cyclosporine, etc

if remission is achieved within 2 weeks of starting prednisone therapy, decreased dose by 25% every 7 days until lowest effective dose is given every other day

[regression of lesions should occur in 2-8 weeks] if remission has not been achieved after 4 weeks of daily prednisone, the case may require combination of prednisone with azathioprine or cyclosporine

firm (solid) elevation that is >1cm

FB, trauma, secondary bacterial infection, kerion (deep dermatophytosis)

skin, lymph nodes, lungs, eyes, CNS

FNA or from draining tract, maybe impression smears from ulcerated areas

Negative cytology; do sterile biopsy for bacterial and fungal culture.

sterile biopsy for histopathology, aerobic ad anaerobic bacterial culture, fungal culture

send out fresh frozen tissue sample for PCR if you are suspicious of mycobacteria

blasto and crypto

mycobacterium, actinomyces, nocardia

dermatophytosis (kerions), cryptococcosis, blastomycosis, histoplasmosis, coccidiomycosis, sporotrichosis

• gram + filamentous anaerobic rod
• opportunistic commensal flora of mouth and GI
• found in environment/ soil

trauma and contamination of penetrating wounds, migrating FBs (awns, quills) [may take months to years to develop draining tract, non-healing ulcerative nodules]

SQ swelling, draining tract, non-healing ulcerative nodules

anaerobic culture, may take 2-4weeks

• surgical excision or debulking, remove FB
• Penicillin/amoxicillin at least 1 month beyond clinical resolution

• gram + filamentous aerobic rod, partially acid-fast
• soil saprophyte

• both are gram + filamentous bacteria
• Nocardia is partially acid-fast and aerobic, Actinomyces is not acid fast and is anaerobic

cellulitis, ulcerated nodules, draining tracts, lymphadenopathy

FNA of nodules shows filamentous gram + bacteria, aerobic culture to differentiate from actinomyces, +/- biopsy

• if 1 or a few lesions,surgical resection
• antibiotics based on susceptibility of isolate
• combination therapy of antibiotics at least one month past clinical cure

Potentiated sulfas, Mino/Doxycycline, aminoglycosides, Imipenem, Clarithromycin, cephalosporins

• obligate mycobacteria (tuberculosis and lepraemurium- affect immunocompromised)
• saprophytic mycobacteria (affect immunocompetent hosts)- panniculitis
• saprophytic bacteria that affect immunocompromised hosts (feline leprosy)

rapidly-growing, ubiquitous, acid fast

penetrating wound with soil contamination, causing mycobacteria granulomas

fatty tissue; feline inguinal fat pad

non-painful, non-pruritic, firm/ fluctuant SQ nodules that ulcerate and spread outwards

• cytology by FNA or or from draining tract- negative staining microbes with diff quik
• culture from nodule aspirate
• deep biopsy for histopath

• aggressive surgical resection (en bloc resection wit skin flaps)
• antibiotics based on culture, usually for 3-6 months

enrofloxacin, doxycycline, gentamicin, clofazimine, clarithromycin, trimethoprim-sulfonamide

fastidious mycobacterial species probably transmitted by biting insects

nodular skin disease that is usually localized ot the pinnae and head

cytology or histological examination with special staining

usually self-limiting, if not surgical resection is curative

ubiquitous, saprophytic, yeast-like

nitrogen-rich alkaline environments, ie. pigeon droppings

usually by inhalation (ie. preceded by respiratory disease), sometimes primary skin innoculation

cats; upper respiratory signs, polyp-like mass in nostrils or swelling on bridge of nose

• cytology: pyogranulomatous inflammation, large microbes with a clear halo
• biopsy
• latex agglutination test for capsule Ag

narrow-base; broad-base

• Itraconazole**
• Amphotercin B (if severe)
• surgical excision if feasible
• treatment may require 2 years or more

moist, acidic soil rich in organic material near bodies of fresh water; endemic in Ohio

inhalation of spores from the environment (ie. preceded by respiratory disease), primary skin inoculation can occur

anorexia, weight loss, cough, ocular disease, lameness, firm nodules, draining tracts, plaques

nose claw beds, face, but can be anywhere

• cytology: big. blue, broad-based budding
• biopsy
• immunoassay Ag (urine)

• Itraconazole
• glucocorticoids in animals with respiratory distress

nitrogen-rich organic soil; bat and bird droppings

inhalation of microconidia, primary skin inoculation can occur

• cytology: intracellular oragnisms
• histopath: round to ovoid with a thinclear zone b/w cell wall and cytoplasm, intracellular
• culture- highly pathogenic- warn lab

cough, weight loss, diarrhea, fever, ocular lesions, papules, nodules, draining tracts, ulcers

Itraconazole, Amphotercin B (severe cases), fluconazole, ketoconazole; usually at least 6 month treatment