Page 1276 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Skin 1251

VetBooks.ir Differential diagnosis results in discharge of pus, which is mucoid, with the
presence of whitish yellow granules. These gran-
Fungal folliculitis; dermatophytosis; dermatophi-
losis; onchocerciasis; other bacterial pyodermas;
therefore an important diagnostic specimen. The
equine demodicosis. ules typically contain the infective organism and are
lesion may present on the shoulder, neck, withers,
Diagnosis ventral abdomen, udder or limbs. Chronically dis-
Deep biopsy for culture and susceptibility testing is charging sinuses at the scrotum may progress to fibro-
carried out. sis and abscessation of the spermatic cord and testes.
Metastasis of purulent lesions to internal organs such
Management as lung, liver, spleen and kidney may occur.
Surgical drainage of larger lesions may be necessary.
This should be followed by skin washes with acceler- Differential diagnosis
ated hydrogen peroxide or chlorhexidine solution. If Habronema infestation; pythiosis; foreign body sinus
surgical drainage has been required, treatment with drainage.
parenteral antibiotics such as penicillin (24,000 IU/
kg i/m q24 h for 3–7 days) or oral antibiotics such Diagnosis
as trimethoprim/sulphadiazine (30 mg/kg p/o q24 h Diagnosis is based on the history of the type of
until 7 days past clinical resolution) may be required. injury and biopsy for histopathology.
All in-contact equipment must be fumigated and
hygiene improved. Management
Surgical excision should be performed, with subse-
Prognosis quent administration of antibiotics such as penicillin
The prognosis is guarded and this condition can be (24,000 IU/kg i/m q24 h for 3–7 days) or oral antibi-
very slow to resolve. otics such as trimethoprim/sulphadiazine (30 mg/kg
p/o q24 h until 7 days past clinical resolution).
BACTERIAL GRANULOMA
(BOTRYOMYCOSIS) Prognosis
The prognosis is guarded, because reinfection can
Definition/overview occur following surgery, with a return of a similar
Botryomycosis is a pyogranulomatous lesion associ- clinical entity.
ated with skin injury.

Aetiology/pathophysiology 12.46
It is caused by lacerations, puncture or a post-
surgical complication of the skin followed by infec-
tion, typically by Staphylococcus spp. and occasionally
Actinomyces spp., which slowly progresses to multiple
miliary interlinking abscesses discharging through
multiple sinuses.

Clinical presentation
Alopecia, a slowly healing wound, induration of the
edges and chronic purulent discharge from one or
more sinuses, with rosette formation of granulation
tissue around sinuses, may be observed (Fig. 12.46). Fig. 12.46 Bacterial granuloma (botryomycosis
The lesion may be large (10–20 cm in diameter), soli- lesion) showing many discharging sinuses in the
tary and resemble a tumour. Rupture of the nodules granulation tissue.