Nylon Allergies in Dogs

Nylon is a commonly used synthetic polymer that can be processed into a large number of fibers, films, or shapes using heat. Although it is very rare for allergies to nylon to develop, it is possible, though allergies to chemicals that are used to form, dye, and protect the material are often found to be the culprit when skin reactions do occur. Contact allergies can be just as unsightly, uncomfortable, and difficult to diagnose for our canine companions as they are for us, and medical attention should be obtained.

Skin allergies are an overactive reaction of the immune system to a protein that the body sees as an intruder. Canine allergies to synthetic polymers such as nylon are rare but not unheard of.

Skin reactions that are not centered on the contact area are generally concentrated around the face and groin as well as under the front legs and between the toes. Frequent contact vectors can include collars, clothing, and carpet. 

• Bald patches
• Blister-like lesions
• Chronic ear infections
• Chronically inflamed feet
• Face rubbing
• Head shaking
• Hives
• Obsessive licking
• Paw biting
• Skin infections
• Skin rashes
• Ulcerations on skin

Types 

Nylon may be included in such diverse products as:

• Carpeting
• Clothing
• Collars
• Cookware
• Dog toys
• Fishing line
• Leashes
• Rope
• Sutures
• Tents
• Toothbrushes

Fortunately, allergies to nylon are very rare, and many times what appears to be an allergy to nylon is actually an allergy to the chemicals used to process the nylon into a final product.

Contact allergies are brought about in the canine body by the aggressive response of specialized immune cells to the allergen. These specialized cells are named mast cells, and it’s their job to protect the body from pathogens. When the immune system is activated by a particular allergen, in this case, nylon, it manufactures a protein that causes the mast cells to release a naturally occurring compound called histamine. Histamine has an inflammatory effect on the tissues it comes into contact with, which can result in the itchy and inflamed skin conditions characteristic of an allergic reaction in canines.

The allergy symptoms that your dog will be showing during the general physical should prompt your veterinarian to collect a skin scraping. The skin samples obtained will then be examined by a microscopic evaluation of the skin cells called cutaneous cytology. This test is completed in order to search for problems like mites or yeast infections. Allergies to materials like nylon can manifest anywhere on the body, although reactions from skin allergies are often centered around the face and groin areas, as well as under the front legs and between the toes. 

If an environmental allergen is suspected, your veterinarian may recommend a patch test, also known as an intradermal skin test. Miniscule amounts of the suspected antigens are injected under the skin in a particular pattern so that a localized reaction can be induced, however, unless nylon is already suspected it may not be included in the allergens tested for as it is not a common allergen for dogs or humans. A thorough history of your canine’s health and a timeline of symptoms may be more beneficial to finding an accurate diagnosis.  Many doctors choose to try to diagnose which allergen is causing the reaction by eliminating suspected allergens from the environment first.

Salves and shampoos made with hydrocortisone will generally relieve the skin discomfort, although it is important to ensure that your pet does not lick the preparation off of themselves as it can be somewhat toxic itself. Although oral and topical antihistamines are generally effective in humans, they are only helpful for twenty to thirty percent of canines and have a tendency to lose effectiveness over time. If neither the antihistamines or topical hydrocortisone are successful in reducing symptoms, then corticosteroid injections or oral tablets may be warranted. 

Although these medications are usually very effective in reducing the signs of allergy, the side effects can be damaging. The long-term side-effects can contribute to serious disorders such as diabetes and liver dysfunction, so concurrent monitoring of the blood chemistry levels is generally recommended. The side-effects are often dose dependent, so the lowest effective dose of corticosteroid should always be employed to avoid them. Animals that are plagued by unavoidable or severe allergic reactions may be considered for the option of injected immunotherapy, especially in reactions that are present for at least four to six months of the year and are resistant to antihistamines. Advancements in sublingual immunotherapy treatments have been made, and recent trials are promising, but this option is not commonly available at this time.

If your dog has developed an allergy to nylon, your veterinarian will give you specific instructions on how to treat symptoms until you are able to eliminate the allergen from the environment. Instructions regarding oral and topical medication should be followed faithfully, and administration may need to be continued even if the symptoms are no longer apparent. Bacterial infections are common with skin allergies and in those cases antibiotics will be prescribed.  Stopping medications before any bacterial infections have been completely eradicated may cause the infection to reoccur.