Flea Bite Hypersensitivity Research Articles

Reliability of different sets of criteria in diagnosing canine atopic dermatitis applied to a population of 250 dogs seen in a veterinary teaching hospital.

Different sets of criteria are available in veterinary dermatology for the diagnosis of canine atopic dermatitis (cAD); there are limited data to assess their reliability. The aim of this study was to assess the discriminative and predictive ability of four sets in diagnosing cAD in a population of dogs with different skin diseases. Two hundred and fifty dogs examined in the dermatology unit of a veterinary teaching hospital. Dogs were diagnosed with cAD, flea infestation (FI), flea bite hypersensitivity (FBH), sarcoptic mange (SM) and other skin diseases (OD). FI, FBH and SM were pooled in one group of dermatoses mimicking cAD (MD). All nonatopic dogs were grouped as a "global population" (GP). Four criteria sets were applied to all dogs. For each set of criteria, sensitivity, specificity, positive and negative predictive values (PPV, NPV), likelihood ratios (LR) and diagnostic odds ratio (DOR) were calculated. When applied to the GP, sensitivities ranged from 54 to 83%, specificities from 68 to 75% and PPVs from 35 to 43%. NPVs ranged from 87 to 94%. LRs and DORs were poor. When applied to MD, sensitivities remained unchanged, specificities and PPV were mildly higher, whereas NPVs were mildly lower and LRs and DORs were comparable. This study showed that each set of criteria had a low diagnostic reliability when used alone. The use of more discriminant criteria integrated into a thorough clinical approach excluding MDs should be considered.

Atopic dermatitis

Canine atopic dermatitis (CAD) is a common genetically predisposed inflammatory and pruritic disease. CAD is a diagnosis made by the exclusion of other pruritic skin diseases such as ectoparasites, and other allergies such as flea bite hypersensitivity, and cutaneous adverse food reaction. Nurses can play an important part in helping to investigate the underlying causes of pruritus in dogs, it is therefore important they have a good working knowledge of the clinical presentation of this common disease and the appropriate diagnostic tests that are routinely used to help rule out other causes of pruritus. Therapy can include systemic medication such as essential fatty acids, antihistamines, glucocorticoids, ciclosporine, Janus kinase inhibitors, monoclonal antibodies to IL31 and allergen specific immunotherapy.

Assessment of the speed of flea kill of lotilaner (Credelio\u2122) throughout the month following oral administration to dogs

BackgroundLotilaner (Credelio™, Elanco), a novel isoxazoline, is a systemic insecticide and acaricide that is rapidly absorbed following oral administration to dogs and has a half-life of 30 days. As part of a development program, studies were undertaken to investigate lotilaner’s initial and sustained efficacy and speed of kill against fleas.MethodsFour studies were conducted to evaluate the onset of lotilaner’s speed of flea knockdown at the time of treatment, and to determine the sustained speed of flea kill (SOK) up to 35 days post-treatment. Each study assessed one or two specific time points (4, 6, 8 and 12 h) post-treatment and following weekly re-infestations. In each study, dogs were randomised to a lotilaner or an untreated group based on pre-administration flea counts, and before treatment were infested with adult Ctenocephalides felis. Dogs randomised to a lotilaner group received a single treatment on Day 0, at the minimum recommended dose rate of 20 mg/kg, 30 (± 5) minutes after being fed. Efficacy was calculated using geometric, and arithmetic mean flea counts in treated versus untreated groups.ResultsOn Day 0, lotilaner efficacy was 89.9% at 4 h, 99.2% at 6 h, 99.9% at 8 h, and 100% at 12 h post-treatment. At each weekly assessment, lotilaner efficacy at 4 h remained at > 97%, at 8 h remained at > 99%, and at 12 h remained at 100% through Day 35. Across all studies, there were no treatment-related adverse events.ConclusionLotilaner’s rapid flea knockdown immediately following treatment and sustained SOK through 35 days post-treatment offers a new solution for helping to eliminate the health risks that accompany flea infestations on dogs. The consistency of the rapid, sustained flea SOK demonstrated in these studies generates confidence that monthly use of lotilaner in dogs can be valuable in disrupting the flea life cycle in a contaminated environment, and that newly acquired fleas will die quickly, thereby reducing the discomfort of flea bites. The sustained lotilaner SOK also provides confidence that there will be no “end-of-dose” resurgence in flea burdens with the potential accompanying consequence of flares in flea-bite hypersensitivity.

Flea and fly bite hypersensitivity: what every nurse needs to know

Fleas are the most important ectoparasites of dogs and cats worldwide. The annual cost to control fleas in companion animals exceeds $1 billion in the USA and €1.1 billion in Western Europe. As well as acting as vectors of disease, and a source of owner revulsion and bite reactions, they are also the most common causes of allergic dermatitis in cats and dogs. Similarly, biting flies are a major source of allergic skin disease in horses. An allergy is an exacerbated response from an individual when it comes into contact with foreign substances (allergens) such as flea and fly saliva. This article considers mechanisms of flea and fly bite sensitivity, diagnosis, and the role of the veterinary nurse in the prevention of these diseases.

Eosinophilic granuloma complex in the cat

Eosinophilic granuloma complex (EGC) is a common feline dermatological reaction pattern that includes eosinophilic plaques, eosinophilic granulomas and indolent ulcers. Most cases are associated with allergy. Flea bite hypersensitivity is the most common trigger, followed by cutaneous adverse food reaction and atopic dermatitis. Investigations should include a thorough elimination of ectoparasites and the institution of a strict dietary exclusion trial before in vitro or in vivo allergy testing to identify environmental allergens. The most commonly used treatment options include antihistamines, glucocorticoids and ciclosporine. Allergen specific immunotherapy can be used in cats where EGC is caused by atopic dermatitis.

Feline atopic dermatitis: a retrospective study of 45 cases (2001–2012)

Atopic dermatitis (AD) is recognized as a common cause of pruritus in cats, but it remains incompletely characterized. The aim of the study was to evaluate cases of confirmed feline AD. Fourty-five cats from a dermatology referral practice (2001-2012). A retrospective case record review was carried out using strict diagnostic criteria, including exclusion of flea-bite hypersensitivity and adverse food reaction. Disease prevalence was 12.5%, with domestic mixed (n = 24), Abyssinian (n = 6) and Devon rex (n = 3) cat breeds predisposed. Median age of onset was 2 years (62% <3 years; 22% >7 years; range 3 months to 12 years). Common presentations were severe (82%), nonseasonal (82%), waxing/waning (36%) pruritus, with alopecia/crusting/excoriations and/or erosions/ulceration (73%). Miliary dermatitis (20%) and eosinophilic granuloma complex lesions (27%) occurred. The face/head (71%), ventral abdomen (51%), neck (51%), limbs (38%), pinnae (31%), dorsum/rump (31%) and feet (16%) were frequently affected sites; lesions were restricted to the head/neck in only five cats (11%). Concurrent otitis externa (16%), superficial bacterial pyoderma (49%), Malassezia dermatitis (7%), flea-bite hypersensitivity (24%) and adverse food reaction (13%) occurred. Strong reactions on intradermal allergen testing were common (68%; 19 of 30), most frequently to pollens (61%) and/or insects (46%). Good response to ciclosporin (100%; 10 of 10), systemic glucocorticoids (55%; 22 of 40) and allergen-specific immunotherapy (57%; 13 of 23) and good/partial response to antihistamines (67%; 22 of 33) were reported. The prevalence of feline AD was higher than previously suggested, and breed predispositions were confirmed. Severe nonseasonal pruritus was most common, with a varied spectrum of lesions affecting a range of body areas.

Unique presentation of normolipaemic cutaneous xanthoma in a cat

A normolipaemic 7-year-old female spayed Domestic Shorthair was initially presented with a history of pruritus for several years and diagnosed with concurrent atopic dermatitis, flea bite hypersensitivity and adverse food reaction. The hypersensitivities were controlled with cyclosporin, allergen-specific immunotherapy, topical flea control and a restricted diet. Five months after initial presentation, the cat developed a non-healing nodular ulcerated cutaneous lesion in the left axilla and also developed immune-mediated haemolytic anaemic (IMHA). The IMHA was stabilised, but the axillary lesion persisted and progressed to a diffuse, firm, yellowed subcutaneous swelling over the ventral body approximately 20 months later. Histopathology was consistent with cutaneous xanthoma. The cat was normolipaemic and being fed a home-prepared diet of lean kangaroo meat and pumpkin to manage pruritus associated with adverse food reactions. No underlying malignancy was detected on routine screening tests. A diffuse, planar form of cutaneous xanthoma occurring without associated lipaemia has not been previously reported in cats.

Characterization of pruritus in canine atopic dermatitis, flea bite hypersensitivity and flea infestation and its role in diagnosis

In dogs, flea infestation (FI), flea bite hypersensitivity (FBH) and canine atopic dermatitis (CAD) have been mainly characterized by their lesions but never by their pruritus. In clinical practice, many of these dogs exhibit only pruritus. The purpose of this study was to evaluate the characteristics of pruritus in these dermatoses and their potential usefulness for diagnosis. Dogs included were selected from the Oniris clinical data. Cases were selected in which the dogs had only one of the three dermatoses diagnosed. The diagnosis of CAD was based on Prélaud's criteria and positive intradermal tests except flea; for FBH by compatible clinical signs and a response to an intradermal test with flea allergen; and for FI by the presence of fleas. Moreover, in each group, other primary pruritic skin diseases were excluded. Location, behavioural manifestations, seasonality and quantification of the pruritus were evaluated. The statistical analysis used chi-squared test with a P-value <0.05. Three hundred and forty-six dogs were analysed, 91 with CAD, 110 FI and 145 FBH. The period (season) of onset was not statistically different either for each dermatosis or among the three dermatoses. Some locations were highly specific for one dermatosis as follows: ventral abdomen/medial surface of thigh (chewing) and radius/carpus/tibia/tarsus (chewing) in FI; back/dorsolumbar area (chewing) and tail (chewing) in FBH; and paws (chewing/licking) and face/neck (rubbing) in CAD. Some features of pruritus could be suggestive of the causal disease, with possible diagnostic value in pruritic dogs.

The synergistic action of imidacloprid and flumethrin and their release kinetics from collars applied for ectoparasite control in dogs and cats

BackgroundThe control of tick and flea burdens in dogs and cats has become essential to the control of important and emerging vector borne diseases, some of which are zoonoses. Flea worry and flea bite hypersensitivity are additionally a significant disease entity in dogs and cats. Owner compliance in maintaining the pressure of control measures has been shown to be poor. For these reasons efforts are continuously being made to develop ectoparasiticides and application methods that are safe, effective and easy to apply for pet owners. A new polymer matrix collar has recently been developed which is registered for 8 months use in cats and dogs. The basic properties of this collar have been investigated in several in vitro and in vivo studies.MethodsThe effects of imidacloprid, flumethrin and the combination were evaluated in vitro by means of whole cell voltage clamp measurement experiments conducted on isolated neuron cells from Spodoptera frugiperda. The in vitro efficacy of the two compounds and the combination against three species of ticks and their life stages and fleas were evaluated in a dry surface glass vial assay. The kinetics of the compounds over time in the collar were evaluated by the change in mass of the collar and measurement of the surface concentrations and concentrations of the actives in the collar matrix by HPLC. Hair clipped from collar treated dogs and cats, collected at various time points, was used to assess the acaricidal efficacy of the actives ex vivo.ResultsAn in vitro isolated insect nerve model demonstrated the synergistic neurotoxic effects of the pyrethroid flumethrin and the neonicotinoid imidacloprid. An in vitro glass vial efficacy and mortality study against various life stages of the ticks Ixodes ricinus, Rhipicephalus sanguineus and Dermacentor reticulatus and against the flea (Ctenocephalides felis) demonstrated that the combination of these products was highly effective against these parasites. The release kinetics of these actives from a neck collar (compounded with 10% imidacloprid and 4.5% flumethrin) was extensively studied in dogs and cats under laboratory and field conditions. Acaricidal concentrations of the actives were found to be consistently released from the collar matrix for 8 months. None of the collar studies in dogs or cats were associated with any significant collar related adverse event.ConclusionHere we demonstrated the synergism between the pyrethroid flumethrin and the neonicotinoid imidacloprid, both provided in therapeutically relevant doses by a slow release collar matrix system over 8 months. This collar is therefore a convenient and safe tool for a long-term protection against ectoparasites.

Factors affecting allergen-specific IgE serum levels in cats.

Pruritic skin diseases are common in cats and demand rigorous diagnostic workup for finding an underlying etiology. Measurement of a serum allergen-specific IgE in a pruritic cat is often used to make or confirm the diagnosis of a skin hypersensitivity disease, although current evidence suggests that elevated allergen-specific IgE do not always correlate with a clinical disease and vice versa. The aim of the study was to to assess the possible influence of age, deworming status, lifestyle, flea treatment, and gender on allergen-specific IgE levels and to evaluate the reliability of IgE testing in predicting the final diagnosis of a pruritic cat. For this purpose sera of 179 cats with pruritus of different causes and 20 healthy cats were evaluated for allergen-specific IgE against environmental, food and flea allergens using the Fc-epsilon receptor based enzyme-linked immunosorbent assay (ELISA) test. The results of the study showed positive correlation between age, outdoor life style, absence of deworming, absence of flea control measures and levels of allergen-specific IgE. Gender and living area (urban versus rural) did not seem to affect the formation of allergen-specific IgE. According to these findings, evaluating allergen-specific IgE levels, is not a reliable test to diagnose hypersensitivity to food or environmental allergens in cats. On the contrary, this test can be successfully used for diagnosing feline flea bite hypersensitivity.

真皮浅層および深層における好酸球浸潤：アトピー性皮膚炎，食物アレルギーまたはノミアレルギーの猫から採材した皮膚生検標本に関する後ろ向き研究

真皮浅層および深層における好酸球浸潤：アトピー性皮膚炎，食物アレルギーまたはノミアレルギーの猫から採材した皮膚生検標本に関する後ろ向き研究

Monitoring of basophil sensitization to antigens of the cat flea (Ctenocephalides felis felis): a new tool for the diagnosis of feline flea bite hypersensitivity?

Suitability of blood basophils for in vitro diagnosis of flea allergy dermatitis (FAD) or flea bite hypersensitivity was studied in cats. A functional in vitro test (FIT) for sensitized type I allergic effector cells was used to evaluate the degree and kinetics of in vivo basophil sensitization against flea antigens in cats under long-term flea exposure. FIT results were compared with intradermal (IDT) and serological testing. Before, during, and after weekly repeated exposure to Ctenocephalides felis; 14 cats were repetitively FIT-assessed for general and flea-specific sensitization. In three cats, flea-specific sensitization was seen before and throughout flea exposure. Five cats, although generally sensitized, never developed a flea-specific sensitization. Six cats initially FIT-negative became sensitized for flea antigen during flea infestation. Induction, upregulation, and binding of C. felis-specific sensitizing antibodies to basophils during flea challenge may explain the developing sensitization in these cats. Strong discrepancies between the levels of flea-specific circulating IgE and basophil sensitization contrasted comparable results for basophil and mast cell sensitization using FIT and IDT, respectively. Hence, the FIT might provide an immunological supplement to the clinical diagnosis of FAD in cats by elucidating the state of basophil-sensitization to flea antigens. And it may be a comfortable alternative to IDT.

The diagnosis of flea bite hypersensitivity in dog - methods and techniques.

Flea bite hypersensitivity is an allergic reaction to the bites of dog-flea (Ctenocephalides canis), cat-flea (Ctenocephalides felis) or human-flea (Pulex irritans)

Epidemiology of flea infestation of ruminants in Libya

The results of an epidemiological and clinical study of flea infestations of farm animals in northern Libya is reported. Of 12,130 sheep examined from 124 flocks, 150 sheep were found to be infested with fleas from 50 different flocks. Likewise 23 goats from 2981 examined, and 11 calves from 1124 cattle examined were infested No fleas were recovered from camels or horses. Of 1861 fleas recovered from farm livestock, 1857 were Ctenocephalides felis strongylus and 4 were Pulex irritans. Dogs from farms and local clinics were also examined. Eight farms dogs were found to be infested with P. irritans. Of 79 infested dogs examined in veterinary clinics, 53 were found infested with P. irritans, 11 with Ctenocephalides felis felis, 12 had a mixed infestation of P. irritans and C. felis felis. Single dogs had mixed infestation of P. irritans and C. canis; C. felis felis and C. canis; and P. irritans, C. felis felis and Echidnophaga gallinacia. C. felis felis was also found on 15 infested cats. C. felis felis was never found on large farm animals despite frequently sharing their environment with dogs or cats. Likewise C. felis stongylus was never isolated from dogs or cats. This is consistent with the hypothesis that C. felis strongylus has become adapted to large farm animals, whilst C. felis felis is better adapted to dogs and cats. However, four stockmen were found infested with a total of 176 C. felis strongylus, which suggests that this subspecies is also a potential zoonosis. A significantly higher proportion of intensive farms had animals with flea infestation compared to semi-intensive farms. Fleas were not found in nomadic herds. Infested farm animals often presented with excoriation, alopecia, pruritis and hyperkeratitis particularly on the lower limbs. These signs are consistent with the generation of flea-bite hypersensitivity.

Feline flea allergy dermatitis

Flea allergy dermatitis (FAD) also referred to as flea bite hypersensitivity (FBH) is the most common pruritic skin disease of cats. In the vast majority of cases, the cat flea, Ctenocephalides felis felis. (C. felis), is isolated (Dryden, 1989; Dryden and Rust, 1994). Fleas are undesirable ectoparasites that in addition to FAD may cause anaemia, transmit Dipylidium caninum, Rickettsia felis and Bartonella henselae which is responsible for cat scratch fever (Kelly et al 2005) and potentially act as vectors for the feline immunodeficiency and feline leukaemia viruses (Vobis et al. 2003a;Vobis et al. 2003b).This article summarises the life cycle of the cat flea and then deals with the immunopathogenesis, clinical signs, diagnosis and management of feline FAD.

Management of feline miliary dermatitis: a clinical update

THE prevalence of miliary dermatitis ‐ variably called feline allergic miliary dermatitis, miliary eczema, eosinophilic dermatitis and papulocrusting dermatitis ‐ is unknown, although many authors suggest that the condition is...

P‐67 Characteristics of the 10 most frequent feline skin disease conditions seen in the dermatology clinic at the National Veterinary School of Nantes

Few studies have presented general epidemiologic data in veterinary dermatology. The aim of this study was to analyse feline dermatological cases seen at the National Veterinary School of Nantes. Animals presented to the clinics are systematically examined with a protocol that allows validation in a computerized system. Seventy prospective codified parameters are collected at each visit (habitat, nutrition, lesions and localisation, laboratory procedures, hypothesis/diagnosis). The final diagnosis in dermatology may combine several causes or diseases. The study included 783 cases seen from January 1992 to January 1997. The following results indicate the frequency of primary diagnosis and frequency of association or suspicion, respectively. The ten most frequent dermatoses were: flea infestations (24.1/33.3%), flea bite hypersensitivity (22.3/42.9%), dermatophytoses (9.9/26.2%), Otodectes (11.5/19%), food allergy (2.8/25.2%), miscellaneous hypersensitivities (2.8/10%), atopy (2.4/22.4%), miscellaneous external otitis (2.4/5.6%), superficial pyodermas (1.4/4.7%), and psychogenic alopecia (1.3/4.7%). In total, flea‐associated problems were identified as the primary cause in 46.5% of cases and hypothesized to be associated in 29% of other cases. Feline miliary dermatitis syndrome was seen in 158 cats (20.2%), feline eosinophilic granuloma complex in 76 cats (9.2%), and extensive alopecia in 58 cats (7.4%). Funding: Self‐funded.

Flea Bite Hypersensitivity: New Aspects On The Involvement Of Mast Cells

A study was performed to test the effect of sensitization to flea antigen, followed by exposure to fleas on mast cells (MCs), their subtypes, and IgE+ cells. Biopsies were taken from flea-sensitized dogs ( n=28) and non-sensitized dogs ( n=5) that had been exposed to fleas. Control groups consisted of flea-sensitized ( n=12) and non-sensitized dogs ( n=9) that were not exposed to fleas. Biopsies, taken before, 24 and 72 h after local flea exposure, were stained with haematoxylin and eosin (H&E), toluidine blue, a double labelling technique for MC chymase and tryptase and anti-IgE. An intradermal test for flea antigen was performed and serum titres of allergen-specific IgE and IgG were measured. Significantly higher numbers ( P<0.001) of double labelled MCs compared to toluidine blue stained MCs were detectable in flea-sensitized dogs independent of flea exposure. In contrast, in non-sensitized dogs, the number of toluidine blue stained MCs and the number of double labelled MCs did not differ. In flea-sensitized dogs after flea exposure the percentage of C-MC was significantly increased at day 1 ( P<0.001) and day 3 ( P<0.001), whereas the percentage of TC-MCs decreased significantly at day 1 ( P<0.001) and day 3 ( P<0.05). The percentage of T-MCs decreased ( P<0.05 day 0 versus day 1; P<0.05 day 0 versus day 3). No significant difference was detectable after toluidine blue staining and staining for IgE+ cells between the groups nor between the MC density and the number of IgE+ cells. All flea-sensitized dogs had positive skin tests to flea antigen and high serum titres of flea-specific serum IgE and IgG antibodies. In non-sensitized dogs, these results were negative. Our data provide strong evidence for an upregulation of MC proteases during the process of sensitization and a generalized selective release of mast cell tryptase after exposure to the antigen.

Subepidermal linear alignment of mast cells in inflammatory dermatoses of the dog.

A recent study demonstrated that 47.7% of dogs with Malassezia dermatitis had a subepidermal linear alignment of mast cells (SLAM). A retrospective histopathological study was conducted on 419 canine skin biopsies to determine if a SLAM was present in other inflammatory diseases. Cases examined included dogs with demodicosis, sarcoptic mange, dermatophytosis, pemphigus foliaceus, pemphigus erythematosus, discoid lupus erythematosus, systemic lupus erythematosus, erythema multiforme, dermatomyositis, staphylococcal pyoderma, primary seborrhea, arthropod bites, contact hypersensitivity, flea bite hypersensitivity, atopy, and food hypersensitivity. Three cases (3/419, 0.7%) were identified with SLAM. The diagnoses for these cases were atopy (1/23, 4%) with a secondary bacterial folliculitis (1/136, 0.7%), pemphigus erythematosus (1/18, 6%), and discoid lupus erythematosus (1/16, 6%). Based on this study, SLAM is significantly more common in Malassezia dermatitis than in other inflammatory diseases.

973 Non-allergen IgE and IgG epitopes are present on recombinant Cte f2, an allergen of flea bite hypersensitivity

973 Non-allergen IgE and IgG epitopes are present on recombinant Cte f2, an allergen of flea bite hypersensitivity