Carpet deodorizer as a contact allergen in a dog

Allergic contact dermatitis was diagnosed in a 7-year-old dog. Clinical signs and history were consistent with a contact allergen being the cause of pruritic skin disease. Patch testing confirmed that carpet deodorizer was the allergen.     

Seasonal allergic dermatitis in sheep associated with Ctenocephalides and Culicoides bites

The clinical, epidemiological and histopathological findings of two pruritic dermatites in sheep in Israel are described. The first type of dermatitis affected mainly young animals with lesions predominantly on the legs. It occurred from March to November, with a peak in June. The second type affected animals of all ages and was mainly on the ventrum. It was sporadic but occurred throughout the year with a peak in October. The morbidity rate of this syndrome reached 4.3% in one flock. The histopathology of both conditions was consistent with an allergic dermatitis. Fleas and midges were collected and identified as Ctenocephalides felis felis and various species of Culicoides. The population density, seasonal activity, geographical distribution and feeding behaviour preferences of the insects and the incidence of the two types of dermatitis suggest that fleas and midges were the causal agents. Flea and midge bite pruritic dermatoses should be considered in the differential diagnosis of sarcoptic and psoroptic mange.     

Sarcoptes scabiei infestation of a donkey in the UK

Sarcoptes scabiei infestation was identified as the cause of pruritic dermatitis in a donkey in the UK. Treatment with i.m. doramectin and topical selenium sulphide was successful in eliminating clinical signs. Foxes were identified as the possible source of infestation. Sarcoptic mange should be considered as a potential differential diagnosis for pruritic dermatitis in equids in the UK.     

FC-46 Methicillin-resistant Staphylococcus intermedius organisms from the vertical ear canal of dogs with end-stage otitis externa

Different mite species generally found on animals may temporarily also infest humans. Consequently, these arthropods may be responsible for pruritic skin reactions that are often misdiagnosed. Mite dermatitis caused by the tropical rat mite Ornithonyssus bacoti occurs in several small mammals and rodents under tropical and temperate climatic conditions. According to various observations in Germany, O. bacoti appears in wild rodents more frequently than previously thought. In most cases, symptoms of mites are recognized only when they attack humans, but the diagnosis of rat mite dermatitis requires identification of the parasite, which is more likely to be found in the environment than on the hosts' skin itself. Here, five different outbreaks from Bavaria are reported. A clinical example is the case of a 23-year-old medical student and several other residents inhabiting a rat- and mouse-infested house in Munich. The arthropods originally came from an Italian restaurant and surrounding facilities. Mites were found in large numbers in the students' flat. The patient was suffering from severe itching and papular urticaria. He consulted a dermatology clinic complaining of a pruritic dermatitis of 2-weeks duration. Dermatitis was misdiagnosed as allergy and treatment with an anti-inflammatory agent was unsuccessful. Eradication of rodents and treatment of the house with a pyrethroid were performed to prevent reinfestation. Ornithonyssus bacoti is a periodic haematophageous parasite and spends a relatively short time on the host. Causal therapy with antiparasitic agents on human patients is not necessary. If indicated, treatment should be symptomatic.
Funding: Self-funded.     

Contact dermatitis in the dog. A review and a clinical study

Allergic, irritative and photosensitive contact dermatitides make up a group of dermatoses which have traditionally been associated with some difficulties in diagnostication. The reason for this is the problems encountered in setting up, keeping in place, and reading the patch test which is the diagnostic tool relevant to veterinary practice. In the present study, a review of the disease complex is given, and a clinical study, dealing with allergic contact dermatitis, performed with materials and methods available to the small animal practitioner, is discussed with regards to symptomatology, diagnostic work, and therapy. With appropriate management, consisting in an attempt to eliminate the offending item(s), and glucocorticoid therapy adjusted to the clinical response, the disease carries a good prognosis.     

Contact dermatitis in dairy cattle caused by calcium cyanamide

Nine of 250 cows on a dairy farm initially developed severe dermatitis on parts of their bodies that touched the floor, and it then spread over their entire body. The cause was suspected to be calcium cyanamide, which had been added to the material spread on the floor to prevent environmental mastitis. Experimental exposure of the skin of a cow to calcium cyanamide induced the same type of contact dermatitis, and histopathological investigations showed that it caused irritant and allergic reactions. To identify the cause of the dermatitis, a patch test with calcium cyanamide and its breakdown products, cyanamide, urea and ammonium bicarbonate, was carried out on four cows. Three of them had a positive reaction to calcium cyanamide and cyanamide; delayed and amplified reactions suggesting an allergic response were observed.     

Aetiology of canine otitis externa: a retrospective study of 100 cases

The objective of this retrospective study was to investigate in 100 dogs with otitis externa (OE) the possible associations between signalment, history, clinical and laboratory findings and the various primary, secondary and perpetuating causative factors of ear canal inflammation. The age of the dogs ranged from 3 months to 14 years (median: 4.75 years) and they included 45 males and 55 females. Cocker spaniels, Jura des Alpes and Brittany spaniels were significantly overrepresented among dogs with OE when compared to the hospital canine population. In the majority of the cases, OE was chronic-recurrent (63%) or bilateral (93%). Allergic dermatitis (43/100 dogs), grass awns (12/100) and otoacariasis (7/100) were the most common primary causative factors; no primary factor could be incriminated in 32 cases and more than one was found in three dogs. Malassezia spp. (66/100 dogs), cocci (38/100) and rods (22/100) were the secondary causative factors, while ear canal stenosis (38/100) and tympanic membrane perforation-otitis media (25/100) were the most important perpetuating factors. Atopic dermatitis and adverse food reactions-associated OE was more common in females and dogs with a history of pruritic skin disease, while grass awn-induced OE occurred in cocker spaniels and acute cases. Tympanic membrane perforation was less frequent in atopic dermatitis and adverse food reactions-associated OE, but more common when otoscopic and ear canal cytological examination revealed the presence of grass awns and rods, respectively. Finally, cocci overgrowth was positively associated with ear canal stenosis.     

FC‐45 Mites as newly emerging disease pathogens in rodents and human beings

Different mite species generally found on animals may temporarily also infest humans. Consequently, these arthropods may be responsible for pruritic skin reactions that are often misdiagnosed. Mite dermatitis caused by the tropical rat mite Ornithonyssus bacoti occurs in several small mammals and rodents under tropical and temperate climatic conditions. According to various observations in Germany, O. bacoti appears in wild rodents more frequently than previously thought. In most cases, symptoms of mites are recognized only when they attack humans, but the diagnosis of rat mite dermatitis requires identification of the parasite, which is more likely to be found in the environment than on the hosts’ skin itself. Here, five different outbreaks from Bavaria are reported. A clinical example is the case of a 23‐year‐old medical student and several other residents inhabiting a rat‐ and mouse‐infested house in Munich. The arthropods originally came from an Italian restaurant and surrounding facilities. Mites were found in large numbers in the students’ flat. The patient was suffering from severe itching and papular urticaria. He consulted a dermatology clinic complaining of a pruritic dermatitis of 2‐weeks duration. Dermatitis was misdiagnosed as allergy and treatment with an anti‐inflammatory agent was unsuccessful. Eradication of rodents and treatment of the house with a pyrethroid were performed to prevent reinfestation. Ornithonyssus bacoti is a periodic haematophageous parasite and spends a relatively short time on the host. Causal therapy with antiparasitic agents on human patients is not necessary. If indicated, treatment should be symptomatic. Funding: Self‐funded.     

Successful treatment of Sarcoptes scabiei in a 33‐year‐old pony with underlying pituitary pars intermedia dysfunction

A pony presented with a severe, chronic dermatitis around the ears, neck and trunk of the body, hind quarters and ventral abdomen. The pony was intensely pruritic as was an in‐contact pony and both owners. A superficial skin scraping demonstrated multiple living mites, identified as Sarcoptes scabiei. Equine pituitary pars intermedia dysfunction (PPID) was diagnosed as an underlying, potentially immunosuppressive disorder. The pony was treated for Sacroptes scabiei as well as PPID and is doing well 2 months after initial presentation.     

The ACVD task force on canine atopic dermatitis (II): genetic factors.

Canine atopic dermatitis is commonly diagnosed in pruritic animals. Many studies have attempted to determine the inheritance pattern of both atopic dermatitis and of elevated allergen-specific IgE production. Despite many clinical, laboratory and breeding studies, the mode of inheritance and genetic mutations underlying this disease currently remain elusive.     

Interleukin‐31: its role in canine pruritus and naturally occurring canine atopic dermatitis

Background – Interleukin‐31 (IL‐31) is a member of the gp130/interleukin‐6 cytokine family that is produced by cell types such as T helper 2 lymphocytes and cutaneous lymphocyte antigen positive skin homing T cells. When overexpressed in transgenic mice, IL‐31 induces severe pruritus, alopecia and skin lesions. In humans, IL‐31 serum levels correlate with the severity of atopic dermatitis in adults and children. Hypothesis/Objective – To determine the role of IL‐31 in canine pruritus and naturally occurring canine atopic dermatitis (AD). Animals – Purpose‐bred beagle dogs were used for laboratory studies. Serum samples were obtained from laboratory animals, nondiseased client‐owned dogs and client‐owned dogs diagnosed with naturally occurring AD. Methods – Purpose‐bred beagle dogs were administered canine interleukin‐31 (cIL‐31) via several routes (intravenous, subcutaneous or intradermal), and pruritic behaviour was observed/quantified via video monitoring. Quantitative immunoassay techniques were employed to measure serum levels of cIL‐31 in dogs. Results – Injection of cIL‐31 into laboratory beagle dogs caused transient episodes of pruritic behaviour regardless of the route of administration. When evaluated over a 2 h period, dogs receiving cIL‐31 exhibited a significant increase in pruritic behaviour compared with dogs that received placebo. In addition, cIL‐31 levels were detectable in 57% of dogs with naturally occurring AD (≥13 pg/mL) but were below limits of quantification (<13 pg/mL) in normal, nondiseased laboratory or client‐owned animals. Conclusions – Canine IL‐31 induced pruritic behaviours in dogs. Canine IL‐31 was detected in the majority of dogs with naturally occurring AD, suggesting that this cytokine may play an important role in pruritic allergic skin conditions, such as atopic dermatitis, in this species.     

Recurrent flank alopecia in a Tibetan Terrier

Recurrent flank alopecia is described in a 2-year-old, male, neutered Tibetan Terrier with concurrent atopic dermatitis. The diagnosis of recurrent flank alopecia was made after 3 consecutive years of localised, winter-onset alopecia. The diagnosis was based on history, compatible clinical signs and supportive histopathology. The diagnosis was complicated by the presence of concurrent pruritic dermatitis. To our knowledge this is the first report of recurrent flank alopecia in this breed.     

Clinicopathological,ultrasonographic, and histopathological findings of superficial necrolytic dermatitis with hepatopathy in a cat

This report describes the antemortem diagnosis and antemortem and postmortem findings of superficial necrolytic dermatitis with hepatopathy (i.e., hepatocutaneous syndrome) in a cat. A 5-year-old Maine coon was evaluated because of a history of pruritic alopecia and liver enzyme elevations. Abdominal ultrasonography revealed a reticular pattern to the hepatic parenchyma. Histopathological findings of the liver were nodular regeneration with bands of vacuolated hepatocytes and bile duct hyperplasia, characteristic of the hepatopathy frequently associated with superficial necrolytic dermatitis. Skin histopathology revealed multifocal parakeratosis, midepidermal spongiosis, and basal cell hyperplasia consistent with superficial necrolytic dermatitis.     

Studies on the role of routes of allergen exposure in high IgE-producing beagle dogs sensitized to house dust mites

The current study aimed to investigate the role played by oral, epicutaneous, and inhalation routes of exposure to house dust mites (HDM). The colony of high IgE-producing beagle dogs has been shown to develop pruritic dermatitis compatible with atopic dermatitis following environmental exposure (EE) to HDM. In crossover experiments, the response to EE was compared to two modified challenges, oral exposure (OE) and snood and muzzle exposure (SME). For OE, HDM were fed daily for 3 days. For SME, ingestion of allergen was prevented but there was inhalation and epicutaneous exposure to all body regions except to one ear. In all experiments, dogs were challenged for three consecutive days, and evaluated before, 6 h after exposure and daily thereafter, for 5 days. After a wash-out period, groups were crossed-over so that each dog was randomly challenged to all three protocols. Clinical scores were analysed using least squares analysis of variance. All dogs developed pruritic dermatitis regardless of the protocol. With OE, lesions developed in the same body regions as with EE although scores were lower. This difference became more evident after the first 3 days when OE scores decreased and EE scores continued to increase. The scores of covered and uncovered ears did not differ with SME. Scores for the remainder of the body were significantly lower than for EE. The development of lesions on covered ears supports the importance of inhalation or a systemic reaction to epicutaneous exposure in other areas. It is concluded that all routes are important and have additive effects, that route of exposure does not determine the distribution of lesions and that continuous epicutaneous exposure probably plays the most important role.     

Apparent idiopathic interface disease in a Boer billy goat

An apparently idiopathic interface diseasee in a 2-year-old Boer billy goat is described. Clinical features of the disease were the presence of a pruritic multiple focally disseminated dermatitis with flat-topped, angular, scaly plaques and papules with corrugated surfaces in the skin of virtually the entire body. The aetiology of the disorder in the described case is unknown.     

Allergic contact dermatitis in the dog. Principles and diagnosis

Allergic contact dermatitis is a rare hypersensitivity disorder in the dog. Clinical diagnosis is not easy. Primary lesions are transient. Secondary lesions caused by chronic inflammation and self-trauma are commonly present on typical areas, especially in sparsely haired regions and on the feet. A presumptive diagnosis can be made based on the history, clinical signs, and positive standardized closed patch testing. Histopathology and basophil degranulation testing may also be helpful in supporting the diagnosis and in identifying the offending allergens. However, a definitive diagnosis can be made only after restriction-provocation testing. With better understanding of the pathogenesis and clinical signs, and with increased availability of diagnostic tests (especially a standardized closed patch test), increased recognition of this dermatosis is expected.     

Fatty acid composition of serum lipids in atopic and healthy dogs

Fatty acids are increasingly used in the treatment of canine atopic dermatitis and their beneficial effects are documented in several prospective, controlled studies. Results from recent studies have indicated that atopic dogs have disordered fat metabolism, due to decreased desaturase activity. To further clarify these possible abnormalities, we examined serum fatty acid patterns in dogs with atopic dermatitis and normal controls. Atopic dermatitis was diagnosed according to the diagnostic criteria proposed by Willemse, after elimination of other possible causes of pruritic dermatitis. Both the relative and the absolute amounts of fatty acids in sera were determined by gas chromatography. Differences in the serum fatty acid pattern indicating a reduction in desaturase activity were not detected in atopic dogs when compared with controls.     

Differential diagnosis of feline pruritus

Pruritic skin diseases in the cat are best approached in a problem-oriented fashion. The presentations of pruritic skin disease in the cat include miliary dermatitis, pruritus of the head, scaling and crusting dermatoses, alopecia, erythroderma and exfoliation, eosinophilic granuloma complex, macular and pustular eruptions, and pruritic nodular dermatoses. There is a specific differential diagnosis for each presentation. A rational diagnostic plan, based on the likelihood of each disease in the differential diagnosis, may be formulated for each presentation of pruritus in the cat.     

Canine and feline atopic dermatitis: A review of the diagnostic options

Atopic dermatitis is an inherited pruritic skin disease in dogs and cats. This pruritic skin condition is due to the animal having an allergic reaction to environmental allergens. The environmental allergens that an individual dog or cat is allergic to are specific for that individual animal. Management options for affected dogs and cats include identification of the offending environmental allergens and subsequent avoidance of that allergen, or allergen-specific immunotherapy. Several diagnostic tests are available to veterinarians to try to identify these allergens. The pros and cons of each of these diagnostic tests will be addressed.     

Report of the 3rd Havemeyer workshop on allergic diseases of the Horse, Hólar, Iceland, June 2007

Allergic diseases occur in most mammals, although some species such as humans, dogs and horses seem to be more prone to develop allergies than others. In horses, insect bite hypersensitivity (IBH), an allergic dermatitis caused by bites of midges, and recurrent airway obstruction (RAO), a hyperreactivity to stable born dust and allergens, are the two most prevalent allergic diseases. Allergic diseases involve the interaction of three major factors: (i) genetic constitution, (ii) exposure to allergens, and (iii) a dysregulation of the immune response determined by (i) and (ii). However, other environmental factors such as infectious diseases, contact with endotoxin and degree of infestation with endoparasites have been shown to influence the prevalence of allergic diseases in humans. How these factors may impact upon allergic disease in the horse is unknown at this time. The 3rd workshop on Allergic Diseases of the Horse, with major sponsorship from the Havemeyer Foundation, was held in Hólar, Iceland, in June 2007 and focussed on immunological and genetic aspects of IBH and RAO. This particular venue was chosen because of the prevalence of IBH in exported Icelandic horses. The incidence of IBH is significantly different between Icelandic horses born in Europe or North America and those born in Iceland and exported as adults. Although the genetic factors and allergens are the same, exported adult horses show a greater incidence of IBH. This suggests that environmental or epigenetic factors may contribute to this response. This report summarizes the present state of knowledge and summarizes important issues discussed at the workshop.