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Claw Disorders 177

○ A notable brown line on the claws DIAGNOSIS ○ Usually by a toe amputation; longitudinal
(consisting of a waxy discharge or stain) Diagnostic Overview claw and ungula bed excision may be
VetBooks.ir typically associated with moist interdigital The diagnosis originates with observation ○ SLO: hydropic and lichenoid interface Diseases and Disorders
is a clue for Malassezia overgrowth and is
complex and painful.
of claw abnormalities on physical exam.
dermatitis, paronychia, and pruritus and
dermatitis
other areas of cutaneous involvement such
history, remainder of exam (especially whether
(pemphigus, bullous pemphigoid) and
as body folds (p. 614). Complementary testing is selected based on ○ Rule out other immune-mediated
• SLO one or several claws is/are affected and skin neoplastic conditions.
○ Onychomadesis starts with a single involvement distant to claws), and results of ○ Identify fungal hyphae and arthrospores
abnormal claw on two or more paws; the initial database. or bacterial organisms.
within 2-9 weeks, all claws on all four ○ About 10% of melanomas (identified
paws are affected. Differential Diagnosis by histologic examination) behave
○ Regrowth of short, misshapen, dry, soft, • Single claw affected aggressively.
brittle, and crumbling claws ○ Trauma-induced condition • Radiographs
○ Paronychia is uncommon unless a second- ○ Neoplasia (subungual SCC, subungual ○ Rule out osteomyelitis with bacterial claw
ary bacterial infection is present. melanoma, high-grade mast cell tumors, disease.
• Subungual SCC inverted squamous papilloma, fibro- ○ Bony lysis of third phalanx (P3) and tissue
○ Single, swollen, painful toe with paro- sarcoma, neurofibrosarcoma, eccrine swelling due to neoplasia, particularly with
nychia and associated erosive/ulcerative carcinoma, osteosarcoma, subungual subungual SCC
dermatitis and often loss of the claw keratoacanthoma) ○ Thoracic radiographs: metastasis check
○ Multiple digits can be affected over time in • Multiple claw involvement • Antinuclear antibody (ANA) test to rule in
black Labradors, black standard poodles, ○ SLO the possibility of SLE
giant schnauzers, and rottweilers. ○ Immune-mediated diseases (pemphigus • FeLV/feline immunodeficiency virus (FIV)
• Subungual melanoma complex, bullous pemphigoid, drug erup- serology
○ Solitary, well-circumscribed, dome-shaped, tion, vasculitis, cold-agglutinin disease, • Fine-needle lymph node aspiration if SCC
firm, wartlike growth at claw base dermatomyositis) or melanoma is suspected
○ Varies in size: 0.5-10 cm in diameter ○ Metabolic disease (hypothyroidism, hyper-
○ Possibly pigmented or nonpigmented and adrenocorticism, feline hyperthyroidism) TREATMENT
ulcerated (rare)
○ Primary pulmonary bronchiolar adenocar- Treatment Overview
Etiology and Pathophysiology cinoma, pulmonary SCC, and cutaneous The goal of treatment is to achieve permanent
• Bacterial claw infection SCC with metastasis to digits in cats cure or control of the disease. Sometimes, pallia-
○ Infection is secondary (e.g., trauma if tive management is the only option (e.g., SLO).
one or two claws are infected; if many Initial Database
claws are infected, consider hypothyroid- • Cytologic examination of claw exudates Acute General Treatment
ism, hyperadrenocorticism, immune- ○ Suppurative or pyogranulomatous inflam- • Claw fracture or avulsion: the clinician
mediated condition [pemphigus, vasculitis mation with engulfed bacteria: consistent should trim or file (using a Dremel tool)
or SLO]). with bacterial claw infection any fractured claws, using sedation, anal-
○ Staphylococcus pseudintermedius is the most ○ Broad-based budding yeast consistent with gesia, local/general anesthesia as necessary.
common bacterium isolated. Malassezia infection (p. 614) Remove loose claws, and bandage foot. In
○ Leishmaniasis should be considered in ○ Evidence of acantholytic cells: indicative severe conditions or patients with suspected
endemic areas (the Mediterranean, limited of pemphigus neoplasia, P3 amputation may be necessary;
areas in the United States). ○ Round cell tumor cells: consistent with submit it for histopathology.
• Onychomycosis melanoma • Bacterial claw infections
○ Microsporum canis in cats • Fungal culture (Dermatophyte Test Medium) ○ Antibiotic therapy for 2 weeks beyond
○ Trichophyton mentagrophytes in dogs of claw trimmings and surrounding hair clinical resolution: cephalosporin (e.g.,
○ Malassezia spp in dogs and cats ○ Indicated if a single claw/claw bed is cephalexin 30 mg/kg PO q 12h),
○ Microsporum gypseum and candidiasis involved (p. 247) amoxicillin-clavulanate 22 mg/kg PO q
(yeast) less common ○ Contact laboratory to determine if poly- 12h, or potentiated sulfonamide (e.g.,
• SLO: currently regarded as an idiopathic merase chain reaction (PCR) ringworm trimethoprim-sulfadiazine 15-30 mg/kg
condition. It may be a clinical manifestation testing is suitable for claw samples PO q 12h).
of many different diseases or an immune- • CBC, serum biochemistry profile, urinalysis ○ Topical creams/ointments: silver
mediated condition itself. Current emphasis ○ Evidence of systemic conditions (diabetes sulfadiazine
is to look for potential underlying conditions, mellitus, hyperadrenocorticism, systemic ○ Paw scrubs: 2%-4% chlorhexidine topical
including hypersensitivity disorders (drug, lupus erythematosus [SLE]) soaks q 12-24h for 7 days beyond clinical
food, environmental allergens) and hormonal • Thyroid profile resolution
and metabolic abnormalities before commit- ○ Indicated if multiple claws are affected • Onychomycosis
ting a pet to lifelong therapy. and other consistent clinical signs are ○ Ketoconazole 10 mg/kg PO q 24h,
• Subungual SCC present. Hypothyroidism (in dogs) and itraconazole 5-10 mg/kg PO q 24h, fluco-
○ Neoplasm generally originating from the hyperthyroidism (in cats with onycho- nazole 5 mg/kg PO q 24h, or terbinafine
germinal epithelium of the claw gryphosis) are rare concurrent/causative 10-40 mg/kg PO q 24h given with food
○ Reverse also possible (metastasis from a conditions. for maximal absorption unless using liquid
primary pulmonary neoplasm/carcinoma azoles
to toe), a sequence that is more common Advanced or Confirmatory Testing ○ Long-term antifungal/anti-yeast treatment
in cats than in dogs • Bacterial culture and sensitivity: often S. on a daily or pulse basis (6 months or
• Subungual melanoma: malignant prolifera- pseudintermedius longer), such as 3 days on and 4 days off
tion of melanocytes involving the claw beds • Biopsy for histopathologic exam and special (ketoconazole) or 1 week on and 1 week
in older dogs stains off (itraconazole)

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