Use of induced cutaneous immediate‐type hypersensitivity reactions to evaluate anti‐inflammatory effects of triamcinolone topical solution in three dogs

Abstract

The anti‐inflammatory effect of a triamcinolone topical solution (TTS) was evaluated by use of induced cutaneous immediate‐type hypersensitivity reactions in dogs. Healthy dogs (n = 3) were treated on one side of the lateral thorax with TTS, and on the contralateral side with vehicle solution. After 7 days of treatment, serial dilutions of inflammatory stimuli (histamine, compound 48/80, anticanine IgE, substance P, and morphine sulphate) were injected intradermally on both sides. Resulting immediate reactions were subjectively scored, their diameters were measured in millimetres, and microcirculatory blood flow at each site was measured using laser Doppler velocimetry. The magnitude of the differences between TTS and vehicle‐treated sides varied with the type of measurement and the stimulus used. With compound 48/80, anti‐IgE, substance P, and morphine sulphate‐injected sites, for at least one concentration, the reaction scores and sizes were notably less on the TTS‐treated sides. Punch skin biopsy specimens were obtained from selected sites 24 h after injection. A pathologist examined stained tissue sections and scored each section as to degree of late‐phase dermal cellular infiltrate. Dermal infiltrate scores were generally lower at the TTS‐treated sites; the composite score from all TTS‐treated sites was 30% lower than that from the vehicle‐treated sites. Observations suggest that TTS may be effective in decreasing some aspects of the inflammatory response in canine skin.

A canine model of cutaneous late‐phase reactions: prednisolone inhibition of cellular and cytokine responses

“…13,14,34 Specifically, our study provides new information regarding the cellular and cytokine/chemokine response in LPR following intradermal injection of anti-IgE in dogs. 13,14,34 We have confirmed that the antiIgE-induced LPR in healthy research dogs are grossly and microscopically similar to allergen-induced LPR in dogs with AD 13 as well as to allergen and anti-IgE-induced LPR in humans. 16,[35][36][37] We have shown that anti-IgEinduced canine LPR exhibit increases in the mRNA transcription of several mediators typical of Th2-dominated responses, notably IL-13, IL-5, CCL5 and CCL17.…”

Late-phase reactions to intradermal testing with Dermatophagoides farinae in healthy dogs and dogs with house dust mite-induced atopic dermatitis

“…Late-phase reactions have been reported in clinically normal dogs artificially sensitized to allergen, 12 clinically normal dogs that received intradermal injection with nonallergenic agents that may induce a LPR, [16][17][18] and dogs with spontaneous AD. 14,18 In a study of dogs artificially sensitized to ragweed, 4 of 5 dogs had a macroscopically visible LPR 6 hours after allergen injection.…”

“…14 Compound 48/80 and anti-IgE antibodies have been reported to induce histologic changes consistent with the LPR between 6 and 30 hours after intradermal injection in healthy dogs. [16][17][18] It is interesting to note that in 1 of the studies reporting reactivity to compound 48/80, 16 significant increases in skin-fold thickness, compared with phosphate-buffered saline solution, peaked at 15 to 30 minutes after intradermal injection but largely dissipated by 6 hours. 16 Thus, despite histologic evidence of a LPR, no macroscopically visible reaction was documented.…”

“…11 Allergenspecific hypersensitivity in dogs is often detected by observation of the IR after IDT. There are few reports of the LPR in dogs [12][13][14][15][16][17][18] ; LDR after IDT in dogs with spontanrous, clinical disease has been reported in only 2 studies with small numbers of dogs. To the authors' knowledge, parameters for the optimal performance, evaluation, and interpretation of LPR in dogs have not been reported.…”

Multiple-center study of reduced-concentration triamcinolone topical solution for the treatment of dogs with known or suspected allergic pruritus

“…Topical triamcinolone formulations with a lower concentration have not been evaluated for clinical efficacy in reduction of cutaneous inflammation. Following initial encouraging results for use of a reduced-concentration triamcinolone topical solution (TTS) in dogs with experimentally induced skin inflammation, 4 we sought to determine whether TTS was therapeutically useful. The objective of the study reported here was to determine the efficacy of TTS in dogs for reduction of clinical signs of pruritic inflammatory skin diseases that have a known or suspected allergic basis and to evaluate safety of TTS in dogs during its use.…”