158 DISEASES/DISORDERS
Lesions may be painful on palpation but are most frequently nonpainful and nonpru-
ritic.
Resolved lesions may remain scarred, thickened, and lichenified with follicular cysts.
Chronic lesions predispose the site to recurrent infections.
Regional lymphadenopathy may be prominent in both the dog and cat.
CLINICAL FEATURES
Initial stages:
Accentuation of follicular ostia and follicular papules; chin may be palpated as
“thickened” (Figure 8.1).
Comedones (55% of feline cases remain in this stage), mild crusting, erythemaand swelling of rostral chin.
Progression to a markedly swollen region with numerous erythematous papulesand pustules (folliculitis) (Figure 8.2).
Advanced stages: exudative lesions indicate a secondary deep bacterial infection/
furunculosis.
Lesions may be painful on palpation but are usually nonpainful and nonpruritic.
Previously severe lesions may remain scarred, thickened, and lichenified with follic-
ular cysts.
Cat: eosinophilic granuloma should be considered as a differential if chin swelling is
noted (Figure 8.3).
DIFFERENTIAL DIAGNOSIS
Dermatophytosis
Demodicosis
Foreign body
Contact dermatitis
Eosinophilic granuloma
Juvenile cellulitis
Malassezia dermatitis
DIAGNOSTICS
Skin scrapings: demodicosis.
Fungal culture: dermatophytosis.
Bacterial culture and sensitivity testing: in patients with suppurative folliculitis and
furunculosis that are nonresponsive to initial antibiotic selection.
Impression smear forMalasseziaovergrowth.
Biopsy: dilated keratin-filled hair follicles leading to plugging and dilatation (come-
dones), perifolliculitis, folliculitis and furunculosis; fibrosis in chronic cases.
Bacteria: in the early stages, not seen and cannot be isolated from lesions.
As disease progresses: papules enlarge and rupture, promoting a suppurative folliculi-
tis and furunculosis.