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Adverse Reactions to Topicals


Right now, in the northern hemisphere the weather is warming up and the days are getting longer. This means we get to enjoy the sun and beautiful days out with our friends, family and canine companions. There is a downside to the wonderful weather and that means that it is flea and tick season! So this of course means that it is time to start our pets on preventative care before these little buggers manage to find a home in the fur of our pets. There are a variety of options in regard to options our pets including, oral medications, collars, and of course topicals! The topicals tend to be rather popular and are highly effective. It is applied to a spot on the base of the neck of the animal. This area should avoid being touched while it is wet and your pet should not be bathed for 24 hours after the application of the medication. This period allows the medication to be absorbed by the oil glands. This then allows the medication to be secreted by the hair follicle over a three-month period which is a lot longer than the oral medication. Topicals are also rather beneficial in the fact that they kill fleas and ticks in their adult forms as well as the larva, but they also offer the benefits of repelling mosquitoes. This can help your canine or feline companion feel more comfortable since the bite of the mosquito still makes them want to scratch as well!

Although topicals are an incredible option in terms of preventative care for your pet it is important to be aware of possible adverse reactions. Due to the medication being applied to the fur which shares a border with the skin, it is important to be aware of the possible adverse reactions. Most pets tend to tolerate the medications with no issues; however, if applied directly to the skin it can lead to a reaction due to one or more products in the medication. This does not always have to be an active ingredient as some animals will have similar reactions to other topicals with different active ingredients so they may be reacting to an inactive ingredient. The reactions are restricted to the area of skin that comes in direct contact with the product, so they do not reflect a systemic toxicosis, but rather a local hypersensitivity so there is no need to be concerned about any systemic damage. The reactions that a pet can experience range from alopecia to mild tingling to chemical burns, which is the most severe reaction.

A very common and mild reaction to the medication is alopecia or hair loss. While the medication is absorbed it can lead to some damage of the hair follicle and result in a bald area on your animal companion. This occurs very commonly and this area usually has hair regrowth if the product is not re-applied. It is not of major concerns unless there are further changes to the area such as scab formation, inflammation and irritation as this indicated a more severe reaction than localized alopecia.

Your animal may also notice some mild tingling if the topical is applied. This tingling occurs when the applied product "tickles" the nerve endings in the skin, causing the characteristic sensation that starts 30 minutes after application and can last up to 24 hours This is most commonly experienced by animals when a product contains concentrated pyrethroids such as permethrin, cyphenothrin, and etofenprox. This sensation is particularly irritating to pets as the medication is commonly applied to the base of the neck or in-between the shoulder blades where they cannot reach to alleviate the discomfort. Affected pets, cats especially, may become hyperactive and agitated as they try to move away from the sensation; others may become quiet, subdued and reluctant to move. A more severe reaction is localized dermatitis. In this case body has an inflammatory response to the site of application and the skin will appear red and irritated. In more severe cases of dermatitis, welts or blisters may develop and the skin may ulcerate. To avoid discomfort or any type of reaction the area should be rinsed with water to attempt to remove the product from the skin. If it is not removed it can be very uncomfortable for your pet. In the case of dermatitis if the inflammation has not become a mild redness and resolved seek veterinary attention. Also, always ensure that the treatment is for the correct species and weight as it can lead to the more severe side effects if the incorrect medication is used. Topicals are excellent long term options for flea and tick preventative. It is essential that the correct one is used and that you are aware of the possible reaction since we do want them to itch from the little critters or the medication!


Worldwide Vets LTD

Company  No. 07436 749

4 Burges Close, Southend-On-Sea, Essex, SS1 3JW

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