Dogs suffering from skin allergies are frequently very uncomfortable and, unfortunately, skin allergies can be one of the most difficult and frustrating diseases to treat in dogs.
Skin allergies in dogs cause scratching and itchy skin. The affected dog may have reddened and inflamed skin from scratching. There may be hair loss and even bald patches. There may even be "hot spots" where the affected dog has scratched a raw spot in his skin due to the itchiness associated with skin allergies.
Common Causes of Skin Allergies in Dogs
The most common causes of skin allergies in dogs are:
- flea allergies
- food allergies
- atopy (allergy to environmental allergens which are inhaled)
Skin allergies in dogs are also frequently complicated with bacterial or yeast infections which must be diagnosed and treated in order to resolve the itchiness and inflammation in the affected dog's skin.
Other factors that need to be considered are diseases which can mimic skin allergies. These diseases need to be investigated and ruled out before effective treatment can begin. Diseases which may mimic skin allergies include:
- demodectic mange
- scabies
- pemphigus (several forms are seen)
- Cushing's disease (hyperadrenocorticism)
- hypothyroidism
Common Diagnostic Tests Used to Diagnose Skin Allergies in Dogs
There are numerous tests which are commonly used to help diagnose skin allergies in dogs.
- Flea control trials are commonly implemented as a means of ruling out flea infestation as a potential cause of the skin allergy. It is not uncommon in canine skin allergies to have difficulty finding live fleas on a pet, even when fleas are a contributing or primary cause of the skin allergy.
- Skin scrapings are performed by lightly scraping the surface of the skin with a sharp object. The objective with a skin scraping is to be able to identify mites which may be causing demodectic or other forms of mange.
- Therapeutic trials with medications effective against scabies and other forms of mange may be necessary. Though demodectic mange is usually easily diagnosed with skin scrapings, other forms of mange such as scabies may be more elusive and therapeutic trials may be necessary to rule them out as a potential cause for itchy skin.
- Skin cytology is a diagnostic test which allows the veterinarian to examine the individual cells evident within the diseased skin. Frequently, bacteria and yeast can be identified through skin cytology. Inflammatory cells produced by the dog's immune system may also be seen on skin cytology.
- Food trials are an effective diagnostic tool in diagnosing food allergies. Food trials require feeding an exclusive diet usually consisting of a novel protein source or a hydrolyzed protein source that is unlikely to result in an immune response for the dog.
- Fungal cultures are diagnostic tests which are used to diagnose fungal or ringworm lesions.
- Bacterial cultures help isolate the bacteria responsible for skin infections and help determine what antibiotic the bacteria is most sensitive to. This diagnostic test is most often done in deep-seated skin infections which have been unresponsive to commonly used antibiotics.
- Skin biopsy is a surgical procedure in which a section of diseased skin is collected and examined microscopically. This diagnostic test may be useful in diagnosing endocrine disorders such as Cushing's disease and hypothyroidism and auto-immune diseases such as pemphigus.
- Allergy testing can be done with either blood samples or through skin testing. However, allergy testing is not a tool for diagnosing skin allergies. Instead, allergy testing is a tool which is used once a diagnosis of skin allergy has been reached to determine which items are causing the allergic response. This information make hypo-sensitization to the offending agents possible for the allergic dog.
Diagnosing a skin allergy in a itchy dog is often a complicated procedure involving many different diagnostic tests. However, proper diagnosis is necessary in order to formulate an effective treatment plan for dogs with skin allergies.
