Page 1550 - Clinical Small Animal Internal Medicine

1488 Section 12 Skin and Ear Diseases

multiforme, toxic epidermal necrolysis, cryoglobulinemia Neoplastic and Paraneoplastic
VetBooks.ir and cryofibrinogenemia, graft‐versus‐host disease, acute Disorders Affecting the Skin
eosinophilic dermatitis (Wells‐like syndrome), acute
neutrophilic dermatitis (Sweet‐like syndrome), familial
canine dermatomyositis, and hypereosinophilic syndrome. Male Feminizing Syndrome Secondary
to Testicular Neoplasia
Dermatologic manifestations of canine testicular tumors
Neurologic Disorders Causing are rarely encountered in parts of the world where neu-
Cutaneous Manifestations tering is common. Male feminization occurs most often
with Sertoli cell tumors, affecting 24–57% of dogs with
these tumors. Cryptorchid testes are at greatly increased
Canine Chiari‐Like Malformation
risk for development of neoplasia. The syndrome is
Canine Chiari‐like malformation has been reported thought to be related to estrogen secretion from the
most frequently in young Cavalier King Charles spaniels. tumor, but other factors may play a role as elevated estro-
It can be found in other breeds, and brachycephalic gen levels are not always found. Bilaterally symmetric
small‐breed dogs are predisposed to the condition. alopecia beginning in the perineal, inguinal, and flank
Chiari‐like malformation is a developmental abnormal- regions is most common in affected dogs. Seborrhea,
ity leading to hypoplasia of the occipital bone and thus a comedones, and hyperpigmentation of the skin, particu-
reduced volume of the caudal fossa, the part of the skull larly in the inguinal and perianal areas, can also be seen
that accommodates the cerebellum and brainstem. The in more advanced cases. Gynecomastia, nipple enlarge-
cerebellum variably herniates through the foramen mag- ment, and a pendulous prepuce can be present. A char-
num, crowding the spinal cord and altering the flow of acteristic clinical feature is linear preputial dermatosis: a
cerebral spinal fluid in that region with resultant syrinx line of erythema with variable hyperpigmentation or
formation. It is easily mistaken for a dermatologic condi- comedones extending from the opening of the prepuce
tion, as it often causes persistent unilateral or bilateral along its ventral aspect to the scrotum. Affected male
scratching at the cervical and shoulder regions. A char- dogs may attract other male dogs.
acteristic feature is that some dogs do not actually make The tumor may be palpable in the affected testicle,
contact with the skin when exhibiting the scratching. and the nonneoplastic testicle can atrophy. However,
The presence of pruritus in this area, particularly if it is testicular palpation is not universally abnormal and is
unilateral and not accompanied by skin lesions, should not possible in cryptorchid dogs. Affected dogs can also
increase the suspicion of canine Chiari‐like malforma- exhibit myelosuppression. Approximately 20% of these
tion. Neck pain is a common feature and is found in most tumors are malignant and roughly 10% will metastasize
affected dogs on physical examination. to the lungs and abdominal lymph nodes.
The diagnosis can be made by the very characteristic Although skin histopathology, estrogen levels
clinical signs in a predisposed breed, but definitive diag- ( particularly estradiol‐17‐beta), ultrasonography and
nosis requires magnetic resonance imaging (MRI). The sometimes general bloodwork can be suggestive, the
reader is referred to the neurology section for a more constellation of characteristic clinical signs, histologic
comprehensive discussion of Chiari‐like malformation. confirmation of testicular neoplasia, and response to
castration are diagnostic for the syndrome.
Sensory Neuropathies
Feline Paraneoplastic Exfoliative Dermatitis
Both inherited and acquired sensory neuropathies can
result in cutaneous manifestations. A sensory neuropa- Feline exfoliative dermatitis is a paraneoplastic syn-
thy of English pointers, German short‐haired pointers, drome seen in old and middle‐aged cats with thymomas.
English springer spaniels, and French spaniels results in Skin lesions usually precede systemic signs such as
severe paw licking and chewing progressing to further dyspnea and weight loss. Affected cats show generalized
mutilation of the limbs and autoamputation. This condi- erythema and severe scaling, often beginning on the
tion has also been reported in one miniature pinscher. head and neck but progressing to widespread lesions.
Canine ganglioradiculitis is an inflammatory disease of The scales can become quite large, sometimes in excess
the cranial and spinal ganglia and nerve roots. Affected of 1 cm in diameter. Alopecia is a common finding. Some
dogs develop sensory deficits and mutilation/hyperes- patients also exhibit crusting, and brown keratoseba-
thesia. Cauda equina syndrome can cause lumbosacral ceous material can be present around the eyes and
hyperesthesia, pruritus, and/or self‐inflicted lesions of mouth, in the ear canals, and in the interdigital spaces.
the hindlimb(s). Pruritus is absent to mild unless secondary infections are