Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

Erythema Multiforme Major in a Dog Treated with Intravenous Human Immunoglobulin and Immunosuppressive Therapy.

An ∼12 yr old castrated mixed-breed dog was evaluated for a 7 wk progressive history of intermittent hyporexia, lethargy, and erosive dermatitis. Initial examination revealed disseminated papules and macules coalescing to irregularly shaped and serpiginous plaques with widespread erosion progressing to ulceration. Skin histopathology revealed transepidermal keratinocyte apoptosis with lymphocyte satellitosis and lymphocytic and histiocytic interface infiltrate. Histopathology combined with clinical signs and history were compatible with the diagnosis of erythema multiforme major. Treatment was initiated with multidrug immunosuppression. Following 36 hr with no improvement, intravenous human immunoglobulin (0.45 mg/kg IV) was administered resulting in notable improvement in the dog's attitude and appetite within 2 hr and the dog's skin lesions within 48 hr. Following discharge, the dog improved daily with near complete resolution of dermatologic disease achieved 1 mo postdischarge. All immunosuppressive medications were ultimately discontinued 5 mo following presentation. This is the first report of a dog with erythema multiforme major that has been successfully treated with a combination of intravenous immunoglobulin and immunosuppression.

Effect of pectin, lecithin, and antacid feed supplements (Egusin®) on gastric ulcer scores, gastric fluid pH and blood gas values in horses.

BACKGROUND: The objectives of this study were to evaluate the effects of two commercial feed supplements, Egusin 250® [E-250] and Egusin SLH® [E-SLH], on gastric ulcer scores, gastric fluid pH, and blood gas values in stall-confined horses undergoing feed-deprivation. METHODS: Nine Thoroughbred horses were used in a three-period crossover study. For the three treatment groups, sweet feed was mixed with E-250, E-SLH, or nothing (control group) and fed twice daily. Horses were treated for 21 days, then an additional 7 days while on an alternating feed-deprivation model to induce or worsen ulcers (period one). In periods two and three, horses (n=6) were treated for an additional 7 days after feed-deprivation. Gastroscopies were performed on day -1 (n=9), day 21 (n=9), day 28 (n=9) and day 35 (n=6). Gastric juice pH was measured and gastric ulcer scores were assigned. Venous blood gas values were also measured. RESULTS: Gastric ulcers in control horses significantly decreased after 21 days, but there was no difference in ulcer scores when compared to the Egusin® treated horses. NG gastric ulcer scores significantly increased in E-250 and control horses on day 28 compared to day 21 as a result of intermittent feed-deprivation, but no treatment effect was observed. NG ulcer scores remained high in the control group but significantly decreased in the E-SLH- and E-250-treated horses by day 35. Gastric juice pH values were low and variable and no treatment effect was observed. Mean blood pCO2 values were significantly increased two hours after feeding in treated horses compared to controls, whereas mean blood TCO2 values increased in the 24 hour sample, but did not exceed 38 mmol/l. CONCLUSIONS: The feed-deprivation model increased NG gastric ulcer severity in the horses. However, by day 35, Egusin® treated horses had less severe NG gastric ulcers compared to untreated control horses. After 35 days, Egusin® products tested here ameliorate the severity of gastric ulcers in stall-confined horses after feed stress.

Characterization of IgE-mediated cutaneous immediate and late-phase reactions in nonallergic horses.

OBJECTIVE: To characterize the response of skin of nonallergic horses following ID injection of polyclonal rabbit anti-canine IgE (anti-IgE) and rabbit IgG. ANIMALS: 6 healthy horses. PROCEDURES: Skin in the cervical area was injected ID with anti-IgE and IgG. Wheal measurements and skin biopsy specimens were obtained before and 20 minutes and 6, 24, and 48 hours after injection. Tissue sections were evaluated for inflammatory cells at 4 dermal depths. Immunohistochemical analysis for CD3, CD4, and CD8 was performed, and cell counts were evaluated. RESULTS: Anti-IgE wheals were significantly larger than IgG wheals at 20 minutes and 6 and 24 hours after injection. There were significantly more degranulated mast cells after anti-IgE injection than after IgG injection. There were significantly more eosinophils at 6, 24, and 48 hours and neutrophils at 6 hours after anti-IgE injection, compared with cell numbers at those same times after IgG injection. There were significantly more eosinophils in the deeper dermis of anti-IgE samples, compared with results for IgG samples. No significant differences between treatments were detected for CD3(+), CD4(+), or CD8(+) cells. CONCLUSIONS AND CLINICAL RELEVANCE: Injection of anti-IgE antibodies was associated with the development of gross and microscopic inflammation characterized by mast cell degranulation and accumulation of inflammatory cells, particularly eosinophils and neutrophils. This pattern appeared to be similar to that of horses with naturally developing allergic skin disease, although lymphocytes were not increased; thus, ID injection of anti-IgE in horses may be of use for evaluating allergic skin diseases of horses.