214 DISEASES/DISORDERS
SIGNALMENT/HISTORY
Dogs: very common; cats: uncommon.
Breeds with short coats, skinfolds, or pressure calluses.
German shepherd dog folliculitis and furunculosis: severe and deep pyoderma; only
partially responsive to antibiotics; frequent relapses; familial pattern; often triggered
by an underlying disease; may be an exaggerated response to bacterial antigens.Pedal folliculitis and furunculosis: severe and deep pyoderma affecting the interdig-
ital region; pit bull, English bulldog, Great Dane, mastiff, dalmatian, boxer, German
shepherd, Labrador retriever, golden retriever.Acute or gradual onset.
Variable pruritus: underlying cause may be atopic dermatitis or the staphylococcal
infection itself may be pruritic (bacterial hypersensitivity or atopic-like disease).
CLINICAL FEATURES
Acute moist dermatitis (“hot spot”): self-induced traumatic skin disease with sec-
ondary surface bacterial infection (Figure 13.1).
Intertrigo: skinfold dermatitis caused by maceration of tissue from chronic mois-
ture/anatomical predisposition (facial folds, interdigital, perivulvar, axillae, etc.)
(Figure 13.2).Impetigo (nonfollicular subcorneal pustules): puppy impetigo (poor nutrition, dirty
environment, etc.) and bullous impetigo in older dogs (large flaccid nonfollicular
pustule often caused byE. coliorPseudomonason the nose or glabrous skin; older
patients may be immunocompromised) (Figures 13.3, 13.4).Mucocutaneous pyoderma (MCP) is an idiopathic ulcerative mucosal dermatitis with
crusting and variable degrees of depigmentation. Lesions often involve the lips, alar
folds, perioral, perivulvar, prepuce, and anal regions (Figure 13.5).Superficial pyoderma: usually involves the trunk; extent of lesions may be obscured
by the hair coat; papules, pustules, epidermal collarettes, and hyperpigmented mac-
ules; creates a “moth-eaten” appearance to the hair coat; usually secondary to an
underlying cause such as atopic dermatitis or “atopic-like dermatitis” (Figures 13.6,
13.7).Idiopathic recurrent superficial pyoderma: recurrent pruritic superficial staphylococ-
cal infection (likely subset of atopic dermatitis where atopic-induced pruritus and
recurrent infection are controlled by resolution of the pyoderma).Canine exfoliative superficial pyoderma (“superficial spreading pyoderma”): large
coalescing epidermal collarettes are noted along the lateral trunk due to interfollicular
pustules; common in collie and sheltie breeds; rule out underlying metabolic disease
(Figure 13.8).Deep pyoderma: often affects the chin, bridge of the nose, pressure points, and feet;
may be generalized (Figures 13.9, 13.10); elicits a foreign body reaction due to rup-
tured hair follicle release of hair shaft antigen into the dermis.