Objective—To evaluate the efficacy of the probiotic Lactobacillus rhamnosus strain GG for the alleviation or prevention of clinical signs of atopic dermatitis (AD) in genetically predisposed dogs.
Animals—2 adult Beagles with severe AD and 16 puppies.
Procedures—The 2 adult Beagles were bred twice, with a year between breedings. Lactobacillus rhamnosus GG was administered to the bitch during the second pregnancy and to the puppies of the second litter from 3 weeks to 6 months of age. Both litters were epicutaneously sensitized to Dermatophagoides farinae. Blood samples were collected from puppies every 6 weeks to measure serum titers of allergen-specific IgE. At 6 months of age, all puppies underwent intradermal allergen testing and environmental challenge with D farinae. Clinical signs were scored.
Results—In the first litter, at 6 months of age, 7 of 7 puppies were strongly seropositive for IgE against D farinae, 6 had a positive reaction to intradermal testing, and 7 developed severe clinical signs of AD after the environmental challenge. In the second litter, 7 of 9 puppies were seropositive, 3 had a positive reaction to intradermal testing, and 6 developed dermatitis and pruritus after the challenge. The second litter had a significantly lower serum titer of allergen-specific IgE and milder reaction to intradermal testing, compared with the first litter. Clinical scores did not differ between litters.
Conclusions and Clinical Relevance—Administration of L rhamnosus GG to puppies appeared to reduce immunologic indicators of AD, although no significant decrease in clinical signs was detected.
Objective—To evaluate the pharmacokinetics of pentoxifylline
(PTX) and its 5-hydroxyhexyl-metabolite,
metabolite 1 (M1), in dogs after IV administration of a
single dose and oral administration of multiple doses.
Procedure—A crossover study design was used so
that each of the dogs received all treatments in random
order. A drug-free period of 5 days was allowed
between treatments. Treatments included IV administration
of a single dose of PTX (15 mg/kg of body
weight), oral administration of PTX with food at a
dosage of 15 mg/kg (q 8 h) for 5 days, and oral administration
of PTX without food at a dosage of 15 mg/kg
(q 8 h) for 5 days. Blood samples were taken at 0.25,
0.5, 1, 1.5, 2, 2.5, and 3 hours after the first and last
dose of PTX was administered PO, and at 5, 10, 20, 40,
80, and 160 minutes after PTX was administered IV.
Results—PTX was rapidly absorbed and eliminated
after oral administration. Mean bioavailability after
oral administration ranged from 15 to 32% among
treatment groups and was not affected by the presence
of food. Higher plasma PTX concentrations and
apparent bioavailability were observed after oral
administration of the first dose, compared with the
last dose during the 5-day treatment regimens.
Conclusions and Clinical Relevance—In dogs, oral
administration of 15 mg of PTX/kg results in plasma
concentrations similar to those produced by therapeutic
doses in humans, and a three-times-a-day dosing
regimen is the most appropriate. (Am J Vet Res 2000;61:631–637)
Skin diseases are one of the most common problems seen in veterinary practices around the world. Many patients are presented with severe and/or chronic lesions, often refractory to treatment, and collection of skin biopsies is often beneficial to obtain or confirm a diagnosis and to help guide a management plan for patients. To obtain valuable information from skin biopsies, practitioners should follow recommended guidelines based on drug withdrawal and washout period, identification, and proper collection of skin lesions, which should be at different stages of progression, as well as include a thorough clinical history and differential list. These different steps taken prior to the submission of samples will often increase the chances of a more accurate diagnosis. Practitioners should also understand it may not always be possible for pathologists to provide a definitive diagnosis, but the information provided with skin biopsies can often be used to guide an appropriate treatment plan. This review will present general guidelines and suggestions to help obtain the most diagnostic skin samples for histopathological evaluation.
Oclacitinib was approved in the United States 10 years ago for the management of atopic dermatitis (AD) and allergic skin disease in dogs. Many studies and case reports have been published in the past 10 years on the efficacy and safety of this medication, both at labeled doses to treat allergic dogs and off label to treat other diseases and given to other species. Concerns and confusion have occurred for both clinicians and owners regarding the long-term safety of this drug. The purpose of this review is to present the current knowledge on the efficacy, speed of action, effects on the immune system, and clinical safety of oclacitinib, based on evidence and published literature. We also aim to summarize the lessons learned in the past 10 years and to propose directions for the future.
Preliminary evidence supports a role for IL-31 in equine insect bite hypersensitivity (IBH) and pruritus. Our studies investigated IL-31 and IL-31 receptor-α (IL-31RA) transcription in leukocytes from normal and IBH horses in response to Culicoides nubeculosus.
19 normal and 15 IBH horses were recruited in the summer of 2019 (low-dose study) and 8 normal and 10 IBH horses in the winter of 2022 to 2023 (high-dose study). Normal horses had no history or signs of allergic skin disease, while IBH horses had a history and clinical signs compatible with IBH. Pruritus was scored using a visual analog score or a 1 to 6 grading system.
Whole blood leukocytes were incubated with saline (0.9% NaCl) solution or C nubeculosus (0.26 µg/mL [low dose]; 5 μg/mL [high dose]). Transcription of IL-31 and IL-31RA was measured by quantitative RT-PCR.
Transcription of IL-31 and IL-31RA significantly increased in leukocytes from normal and IBH horses following high-dose C nubeculosus, and no differences were found between populations. Following low-dose C nubeculosus IL-31RA, transcription was increased in both normal and IBH horses, but IL-31 transcription was reduced in normal horses. No positive correlation was found between pruritus scores and IL-31 transcription after low- or high-dose C nubeculosus stimulation.
Exaggerated IL-31 transcription was not identified in IBH horses, suggesting that dysregulation in IL-31 signaling occurs downstream or in localized tissues or involves regulation by yet unidentified receptor splice variants or IL-31-induced increased sensitivity to other pruritogens. Further studies to understand IL-31 signaling in equine allergic skin disease are needed.
Improved understanding of the pathogenesis of atopic dermatitis in dogs has led to more effective treatment plans, including skin barrier repair and new targeted treatments for management of allergy-associated itch and inflammation. The intent of this review article is to provide an update on the etiologic rationale behind current recommendations that emphasize a multimodal approach for the management of atopic dermatitis in dogs. Increasing knowledge of this complex disease process will help direct future treatment options.
Objective—To determine serum pharmacokinetics of pentoxifylline and its 5-hydroxyhexyl metabolite in horses after administration of a single IV dose and after single and multiple oral doses.
Animals—8 healthy adult horses.
Procedures—A crossover study design was used with a washout period of 6 days between treatments. Treatments were IV administration of a single dose of pentoxifylline (8.5 mg/kg) and oral administration of generic sustained-release pentoxifylline (10 mg/kg, q 12 h, for 8 days). Blood samples were collected 0, 1, 3, 6, 12, 20, 30, and 45 minutes and 1, 2, 4, 6, 8, and 12 hours after IV administration. For oral administration, blood samples were collected 0, 0.25, 0.5, 0.75, 1, 2, 4, 8, and 12 hours after the first dose and 0, 0.25, 0.5, 0.75, 1, 2, 4, 8, 12, and 24 hours after the last dose.
Results—Elimination of pentoxifylline was rapid after IV administration. After oral administration, pentoxifylline was rapidly absorbed and variably eliminated. Higher serum concentrations of pentoxifylline and apparent bioavailability were observed after oral administration of the first dose, compared with values after administration of the last dose on day 8 of treatment.
Conclusions and Clinical Relevance—In horses, oral administration of 10 mg of pentoxifylline/kg results in serum concentrations equivalent to those observed for therapeutic doses of pentoxifylline in humans. Twice daily administration appears to be appropriate. However, serum concentrations of pentoxifylline appear to decrease with repeated dosing; thus, practitioners may consider increasing the dosage if clinical response diminishes with repeated administration.