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Tag: pruritis

  • Immunotherapy in cats

    Immunotherapy in cats

    Although “off-licence”, immunotherapy is well worth considering in our pruritic feline friends.

    Feline head pruritus secondary to food allergy
    Feline head pruritus, a result of food allergy. Image by Caroldermoid. Licensed under CC BY-SA 3.0 via Wikimedia Commons.

    Of course we need to rule out all other causes of pruritus first:

    • Ectoparasites: As well as all the usual suspects, don’t forget Demodex can occasionally cause ventral alopecia and pruritus (that’s the funny flat form, not the cigar shaped one).
    • Food allergies: Let’s face it, food allergy is tricky to pursue in cats – and if they have a partly outdoor lifestyle, hypoallergenic diets are of not of any use.

    Case study

    I recently saw a case that had typical excoriation lesions around the head and neck.

    The owner was able to keep the cat indoors on Purina HA Hypoallergenic for six weeks, and was happy to dose monthly with Stronghold. This, together with a good response to steroids, was highly suggestive of atopy.

    Serum IgE testing produced a range of high levels to pollens, house dust mite and moulds.

    Our friend has recently started on immunotherapy injections and is now starting to show signs of a good response. With the feline response to immunotherapy reported to be higher than that in dogs, this may be something well worth considering in cats.

  • Histiocytomas in dogs

    Histiocytomas in dogs

    Histiocytoma
    A histiocytoma on the ear of a boxer dog. Image by Joel Mills (own work) [GFDL, CC-BY-SA-3.0 or CC-BY-SA-2.5-2.0-1.0], via Wikimedia Commons.
    Histiocytomas are common, benign skin tumours that begin in the immune cells. They usually present as small, firm, dome or button-shaped masses on the skin surface, which are fast growing, non-painful, and usually solitary.

    Common sites include the head, nose, ear edges, and limbs. Occasionally, multiple skin nodules or plaques are present. Rarely, an autoimmune blistering is possible that may ulcerate.

    Histiocytomas can also occur internally – in the stomach, lungs and intestines.

    Retrievers, bull terriers, cocker spaniels, and great Danes are more susceptible to histiocytomas. The masses often spontaneously regress over two to three months.

    The most common problem that arise from histiocytomas is when they become pruritic, triggering self-excoriation and infection. Excision is then required.

  • Don’t forget allergen-specific immunotherapy in cats

    Tree pollen
    Not a flea or food allergy… what else could it be?

    Allergen-specific immunotherapy (ASIT) can be a useful tool in cats.

    I see a number of cats that, following parasite elimination and control – plus no response to dietary trial – remain pruritic. We use serological testing via our commercial laboratory and then order in the ASIT vial(s) according to the results.

    Although the efficacy of ASIT is by no means guaranteed, I find it generally works well in cats. In fact, I find the majority are controlled well, although it has to be said we see fewer cases than in dogs.

  • Higher frequency passing stools can indicate adverse food reactions

    Dog on toilet
    It’s worth asking clients how many times a day their dog passes stools. Image ©iStock.com/damedeeso13

    While not exactly a major sign of food allergies, the number of times a day a patient passes stools can raise suspicion of the condition.

    Between 60% and 65% of dogs with adverse food reactions (AFR) have concurrent gastrointestinal disturbance (Paterson, 1995) and (Loeffler, 2004).

    Another study confirmed my impression dogs with AFR produce on average 3 stools a day, compared with an average of 2.1 stools/day in atopic dogs and 1.6/day in normal dogs (Loeffler, 2004). This decreases to normal in dogs with confirmed AFR once managed.

    So, it’s definitely worth asking the question, and given encouraging clients to undertake food trials can be challenging, this can be very helpful in discussions as to the possible causes of pruritus.

    REFERENCES
    Paterson S (1995). Food hypersensitivity in 20 dogs with skin and gastrointestinal signs, Journal of Small Animal Practice 36(12): 529-534.

    Loeffler A et al (2004). Dietary trials with a commercial chicken hydrolysate diet in 63 pruritic dogs, Vet Rec 154(17): 519-522.

  • Role of bacterial colonisation in allergic skin disease

    Beagle
    Pruritus: the unpleasant skin sensation that frequently provokes scratching. Image ©iStock.com/olaser

    As spring warms up, my own nose and sinuses have detected increasing pollen levels, and there’s been a corresponding increase in pruritic patients coming across the threshold.

    I think the role of pyoderma in allergic skin disease is well established and accepted. However, it is not uncommon to see dogs with no obvious skin lesions that are markedly pruritic, and cytology often reveals large numbers of cocci without the correspondingly high levels of inflammatory cells.

    In patients with reduced barrier function, this overgrowth can contribute significantly to the levels of pruritus. I find a significant number of dogs’ pruritus reduces by at least 50%, if not more, with appropriate antibiotic and shampoo therapy when overgrowth is identified by cytology.

    I usually repeat the cytology in around 2 to 3 weeks to check for resolution, although, of course, given the relapsing nature of the condition periodic treatment is required.

    Reference
    Rosenkrantz W (2010). Proceedings of the NAVC Conference 2010.

  • Check for Demodex gatoi in pruritic cats

    Cat scratching neck
    Image ©iStock.com/pixalot

    Demodex gatoi is an unusual cause of pruritus in cats, but given the challenging nature of establishing a diagnosis in cats (Hobi et al, 2011) it is well worth ruling out this parasite as a possible cause (Moriello, 2015).

    Karen Moriello reports finding this more oval, rather than cigar-shaped, form of Demodex more frequently in faeces (by faecal flotation) than on skin scrapes due to the cat grooming and ingesting the mite.

    The good news is that, if we do find the mite, it is possible to treat (off licence) with Advocate Cat once weekly for six weeks.

    References
    Hobi S, Linek M, Marignac G et al (2011). Clinical characteristics and causes of pruritus in cats: a multicenter study on feline hypersensitivity associated dermatoses, Vet Dermatol, 2011.

    Moriello, K.A. (2015). Itchy Cats: Evidence Based Diagnosis and Treatment, North American Veterinary Conference, Orlando 2015.