Small Animal Dermatology, 3rd edition

366 DISEASES/DISORDERS

 S ́ezary syndrome: rare form of CEL; cutaneous lesions: invasion of peripheral lymph

nodes by neoplastic lymphocytes; leukemia develops simultaneously.

 Pagetoid reticulosis: rare form of CEL; lymphoid infiltrate confined to the epidermis

and adnexal structures in the early stages of the disease and extends to the dermis in

the late stages.

SIGNALMENT/HISTORY

 CnEL: older dogs and cats.

 CEL:
Dogs: age range 6–14 years; mean 8.6 years
Cats: age range 12–17 years
No apparent breed or sex predilection.

Historical Findings

 CnEL can be acute and progress rapidly.

 CEL:
Chronic skin disease: months before diagnosis
Mimics other inflammatory dermatoses
Pruritus is uncommon except in Sezary syndrome (severe) ́
Initial findings include erythema, scaling, depigmentation, alopecia, and crust-

ing

Lesions commonly begin in areas associated with allergic conditions, mucocu-

taneous junctions, and oral cavity

Progression to nodular and tumor stages may be rapid; clinical course typically

range 3 months to 4 years.

CLINICAL FEATURES

 CnEL:
Firm, dermal or subcutaneous nodules
Rarely affects the mucous membranes
Usually erythematous to purpuric irregular nodules to plaques (Figures 24.1–

24.3)

Most often multicentric with rapid progression.

 CEL: overlap of four clinical categories of presentation:
Exfoliative erythroderma: generalized erythema, scaling, depigmentation, alope-

cia; lesions begin predominantly on the body; often pleomorphic and initially

static to slowly progressive (Figures 24.4–24.6)

Mucocutaneous: erythema, erosion, and ulceration affecting facial mucocuta-

neous junctions; depigmentation may be extensive, leading to leukoderma; sin-

gle, multiple, and bilaterally symmetrical patches appear; additional mucocuta-

neous junctions may be affected (Figure 24.7)