Dermatophagoides pteronyssinus and Dermatophagoides farinae are all over your house and you probably don't realize it. Commonly referred to as dust mites, these microscopic organisms live in your rugs, linens and bedding, flourishing in darkness and warm, moist air. Though people and pets generally co-exist with dust mites without problems, occasionally a cat will have a sensitivity or allergy to dust mites.
Meet the Dust Mite
Dust mites rely on their environment to sustain them, feeding on viruses, bacteria, fungi and dead skin. Tiny and translucent, they're easy to overlook; most people are sensitized to them since they're a fact of everyday life. Sometimes a cat may have a reaction to the protein in the mites' feces, triggering a host of reactions.
Cat Reactions to Dust Mites
Cats can develop a variety of reactions to dust mites, including ear infections and inflammation, eosinophilic granuloma complex, chin acne, itching and pillow foot, otherwise known as plasma cell pododermatitis.
Eosinophilic Granuloma Complex
When a cat develops an allergic reaction to something, it triggers a reaction in her immune system. The reaction may manifest in three different ways -- separately or simultaneously -- as part of eosinophilic granuloma complex.
- Eosinophilic plaques are round or oval lesions, often located on the thighs or abdomen, and are frequently ulcerated.
- Indolent ulcers are usually found on the upper lip.
- Eosinophilic granuloma is a nodular lesion, often found on the face, in the mouth or on the backs of the thighs.
Anti-inflammatories are usually effective for short-term treatment of eosinophilic granuloma complex.
Plasma cell pododermatitis presents as its nickname implies: The cat's foot pad takes on a swollen, spongy appearance, occasionally with a purplish tint or ulcerations. A trigger, such as an infection or allergen, prompts the plasma cells to produce antibodies in response, usually in more than one foot. Doxycycline and/or coriticosteroids, such as prednisone, are often effective for short-term management of pillow foot.
A cat with acne may look as though her chin is dirty. The tiny bumps can progress to small abscesses, eventually breaking open to form crusts. A cat may scratch, increasing the irritation, eventually leading to swelling and hair loss on the chin, as well as secondary infections. Depending on the extent of the outbreak, treatment can range from shampoos, gels, antibiotics or corticosteroids.
When an allergy manifests in a cat it can change the environment in her ear, resulting in an ear infection, often an early sign of an allergic reaction. Signs of ear infection include:
- Scratching the ears and head
- Shaking or tilting the head
- Discharge in the ears
- Inflammation of the ear canal
Treatment for ear infection due to allergies typically includes regular cleaning with a special solution, antihistamines, supplements and corticosteroids.
Immunotherapy and Immunosuppression
If dust mites are plaguing your cat, there are two treatment options. Immunotherapy targets the specific allergen by creating a tailored allergy serum to be administered to the cat in varying strengths and amounts. As the cat becomes desensitized to the allergen and its effects, the serum dosage is tapered off. Administered as an injectable or as oral drops to be delivered under the tongue, immunotherapy offers the benefit of rare side effects and rapid response.
Immunosuppressive drugs target the cat's immune system to depress it so it doesn't respond to the allergen; corticosteroids and cyclosporine are immune-suppressants.
Controlling the Environment
Eliminating dust mites is impossible, but you can minimize their presence with some thorough housekeeping. If you're able, air out your cat's favorite bedding on a sunny, dry day for 12 hours. Get rid of dust mites on the upholstery, mattresses and cat trees with a steam cleaner; launder her bedding in hot water or a mix of cold water and tea tree oil. Use dust mite covers on your mattresses and vacuum regularly with a vacuum outfitted with a HEPA filter. A HEPA air filter in the house will also cut down on the number of mites she has to deal with.