590 DISEASES/DISORDERS
Clipping too closely can lead to embedded debris and secondary infections, including
onychomadesis; trauma to P3 may cause onychodystrophy (Figure 40.9).
Paronychia (infectious): immunosuppression (endogenous or exogenous), FeLV or
FIV infection (may be associated with plasma cell pododermatitis), trauma, and dia-
betes mellitus.Dogs that dig or hunting dogs.
Dogs with conformational disorders and obesity are at risk due to abnormal weight
distribution and increased friction.
Concurrent diseases increase risk: allergy, immune-mediated diseases, keratiniza-
tion disorders, parasites (e.g.,Demodex,Leishmania, hookworms), metabolic dis-
ease (hepatocutaneous syndrome), neoplasia (epitheliotropic lymphoma, metastatic
bronchogenic adenocarcinoma, squamous cell carcinoma, keratoacanthoma, inverted
papilloma, melanoma, mast cell tumor) (Figures 40.10–40.12).CLINICAL FEATURES
Licking at the feet and/or claw/ungual folds; nail biting.
Lameness.
Pain.
Pruritus.
Swelling, erythema, or exudate within the claw.
Swelling, erythema, or exudate affecting the ungual fold.
Swelling, erythema, or exudate affecting the interdigital region.
Swelling, or erythema affecting the footpad.
Hyperkeratosis, crusting, or ulceration of the ungual fold.
Hyperkeratosis, crusting, or ulceration of the footpad.
Deformity or sloughing of claw.
Deformity or sloughing of the footpad.
Discoloration of the claw (red-brown discoloration associated withMalassezia).
Hemorrhage from the claw or following the loss of a claw.
Previous description of being “tender-footed.”
Malodor.
Paronychia
Infection: bacteria, dermatophyte, yeast, viral (Candida, Malassezia) (Figures 40.13–
40.15).
Parasites:Demodex,Leishmania.
Immune mediated: pemphigus, bullous pemphigoid, lupus erythematosus, drug
eruption, symmetric lupoid onychodystrophy (Figures 40.16, 40.17).
Neoplasia: subungual squamous cell carcinoma, melanoma, eccrine carcinoma,
osteosarcoma, subungual keratoacanthoma, inverted squamous papilloma (Figures
40.18–40.20).Arteriovenous fistula.