Page 1508 - Clinical Small Animal Internal Medicine

1446 Section 12 Skin and Ear Diseases

every 48 hours. Regression of the lesions may take 2–8 Clinical Signs
VetBooks.ir weeks. If remission has not been achieved after four The clinical signs are characterized by firm, hair‐covered
weeks of daily immunosuppressive doses of glucocorti-
to partially alopecic, erythematous papules, nodules, or
coids, the case may require combination therapy with
other immunosuppressive drugs such as azathioprine or plaques. Lesions develop more commonly on the head
and distal extremities, and less commonly on the pinnae,
ciclosporin. Topical and intralesional corticosteroids eyes, trunk, and abdomen. Lesions involving the tongue
have been effective in some cases, and may be the treat- and prepuce have been seen in individual dogs. In most
ment of choice when systemic immunosuppressive ther- cases, the lesions are multiple and are not associated
apy is contraindicated. In addition to immunosuppressive with pain or pruritus. Occasionally, draining tracts and
treatment, vitamin E and potassium iodide have been ulceration can be observed, especially on lesions local-
recommended, but their efficacy is unknown.
ized to the feet (Figure 164.5).
Lymphadenopathy was present in 31% of the cases in a
Prognosis review including 29 dogs. Systemic signs associated with
this syndrome have not been reported. The condition
The prognosis is usually good, with most cases showing may resolve spontaneously or take a waxing and waning
a good response to treatment. Some cases may require course.
prolonged immunosuppressive therapy.

Diagnosis
Sterile Granuloma/Pyogranuloma
Syndrome Clinical differential diagnoses include bacterial and fun-
gal infections, foreign bodies, SNP, cutaneous eosino-
philic granulomas, and cutaneous neoplasms. Diagnosis
Sterile granuloma/pyogranuloma syndrome (SGPS) is an of SGPS is based on its clinical appearance, histopatho-
uncommon disease presenting clinically with cutaneous logic findings, and failure to document the presence of
papules, nodules or plaques of unknown origin. The microorganisms. Wedge biopsies should be performed
lesions may be solitary or multiple, and localized or to collect samples that include the epidermis, dermis,
generalized.
and subcutaneous tissue. The samples should be col-
lected aseptically if they are being submitted for cultures.
Pathogenesis Histopathologically, SGPS is characterized by multifocal,
nodular to diffuse pyogranulomatous/granulomatous
Sterile granuloma/pyogranuloma syndrome is an idio- dermal infiltrates. Special stains on biopsy samples are
pathic canine skin disorder. The pathogenesis is negative. Aerobic and anaerobic bacterial cultures and
unknown, but the inflammatory nature of the infiltrate, fungal culture from fresh tissue samples are also nega-
failure to demonstrate infectious agents, and the good to tive. Some organisms are difficult to culture or identify
excellent response to immunomodulating drugs support with routine methods, and molecular studies such as
it being an immune‐mediated disorder. However, it has
been hypothesized that SGPS may be related to an
immune response against persistent endogenous or
exogenous antigens, such as Leishmania spp. or
Mycobacterium spp. organisms or incomplete clearing of
associated antigens, causing a granulomatous/pyogranu-
lomatous inflammatory reaction. The presence of
Leishmania spp. DNA has been documented in cases of
SGPS in Spain and Italy. The finding of antigenic frag-
ments or organisms may become possible as we advance
our diagnostic techniques.

Signalment
Sterile granuloma/pyogranuloma syndrome can affect
dogs of any age and gender, but in a retrospective study
24/29 cases were male. It is seen more frequently in the Figure 164.5 Partially alopecic, erythematous and ulcerated
nodule present in the interdigital space of digits 4 and 5 in a
Great Dane, boxer, golden retriever, collie, dachshund, dog with sterile granulomatous pyogranulomatous syndrome.
English bulldog, and Weimaraner. Source: Courtesy of Dr Wendy Lorch.